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Journal of Back and Musculoskeletal Rehabilitation 28 (2015) 797–802 DOI 10.3233/BMR-150587 IOS Press
Do psychological states associate with pain and disability in chronic neck pain patients? Zacharias Dimitriadisa,b,∗ , Eleni Kaprelia , Nikolaos Strimpakosa,b and Jacqueline Oldhamb a
b
Physiotherapy Department, T.E.I. of Lamia, Lamia, Greece Manchester Academic Health Sciences Centre, University of Manchester, Manchester, UK
Abstract. BACKGROUND: Chronic neck pain is one of the most usual neuromusculoskeletal pain conditions which can lead patients to chronic disability. Similarly to other pain conditions, the changed psychological status of these patients is believed to be associated with their pain condition and disability. However, the association between the psychological status of patients with idiopathic neck pain and their pain intensity and disability is minimally explored. OBJECTIVE: This study was aimed at investigating the association between psychological states (anxiety, depression, kinesiophobia, catastrophizing) of patients with chronic idiopathic neck pain and self-reported pain and disability. METHODS: Forty five patients with idiopathic chronic neck pain (more than 6 months, at least once a week) participated. Their psychological states were assessed by using the Hospital Anxiety and Depression scale, Pain Catastrophizing scale and Tampa Scale for Kinesiophobia. Self-reported disability was recorded with the Neck Disability Index. Pain intensity was recorded by using a visual analog scale. RESULTS: Neck pain intensity was significantly correlated with anxiety (p < 0.05). Disability was significantly correlated with anxiety, depression and catastrophizing (p < 0.05). Multiple regression analysis showed that pain-induced disability can be significantly predicted by anxiety and catastrophizing (p < 0.05). CONCLUSIONS: It can be concluded that anxiety, depression and catastrophizing of patients with chronic neck pain is associated with their self-reported disability, whereas anxiety is also associated with their pain intensity. Anxiety and catastrophizing may be important predicting markers of patients’ self-reported disability. Keywords: Anxiety, catastrophizing, neck pain, depression, kinesiophobia
1. Introduction Cervical spine studies have shown that chronic neck pain is associated with psychological states such as anxiety, depression, kinesiophobia and catastrophizing [1–3]. These psychological states are believed to lead to a biochemical sequence of events leading to experience of greater pain and disability [4,5]. The same psychological states can also indirectly deteriorate patients’ symptoms due to movement and exercise avoidance or restraining from daily activities [5,6]. These ∗ Corresponding author: Zacharias Dimitriadis, TEI Lamia, Department of Physiotherapy, 3rd km O.N.R. Lamia-Athens, 35100, Lamia, Greece. E-mail: [email protected].
facts reveal that psychologically compromised patients with chronic neck pain may have a more excruciated experience of their condition. The connection of psychological influences of neck pain with pain intensity and disability is a point of interest in many observational studies. However, in patients with idiopathic chronic neck pain the findings are limited and conflicting. Anxiety is one of the most important psychological states that are believed to be associated with the existence of higher levels of pain and disability in musculoskeletal pain conditions. Bru et al. [7] found that anxiety presents a weak correlation with pain intensity. Additionally, Luo et al. [8] recruited a sample comprised mainly of patients with idiopathic chronic neck pain and found that anxiety presents a similar associ-
c 2015 – IOS Press and the authors. All rights reserved ISSN 1053-8127/15/$35.00
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Z. Dimitriadis et al. / Do psychological states associate with pain and disability in chronic neck pain patients?
ation with neck pain disability. Leino and Magni [1] found that the existence of stress symptoms is a significant marker for the development of neck/shoulder pain 5 years after the initial assessment. Depression also seems to be correlated with neck pain and disability although the findings of different studies are not consistent with each other. Luo et al. [8] observed a weak correlation between depression and neck pain disability. In a study by Pool et al. [9] it was found that the depression of neck pain patients cannot predict their recovery. Contrastingly, Mantyselka et al. [3] found that the daily neck pain is a significant predictor of depression. Another study by Rajala et al. [10] also shows that neck pain is frequently observed among depressed individuals. Furthermore, Leino and Magni [1] and Rajala et al. [10] found that the appearance of neck pain can be predicted by depression, whereas a correlation between depression and shoulder/neck pain was also observed by Pollock et al. [11]. Movement avoidance due to fear of pain or re-injury is also considered an important factor for prolonged pain and disability [12]. Kinesiophobia has been found to be associated and to be able to predict chronic neck pain disability [13,14]. Additionally, Pool et al. [9] found that the recovery of patients with sub-acute neck pain can be impeded by kinesiophobia. Although these findings are in contrast with the findings by Hill et al. [2], an association of kinesiophobia with recovery after physiotherapy was also observed. Finally, Thompson et al. [15] did not find any association between kinesiophobia and pain and disability in a sample of patients exclusively with idiopathic chronic neck pain. Catastrophizing is a psychological factor that is also related with increased experience of pain and disability [5]. A study by Pool et al. [9], in a sample of patients with sub-acute whiplash or idiopathic neck pain, shows that the recovery of patients after rehabilitation cannot be predicted by catastrophizing. In contrast, in another study by Hill et al. [2] in patients with nonspecific neck pain, catastrophizing was found to be an important factor for the prediction of recovery of patients after physiotherapy. This association is also highlighted in a study by Thompson et al. [15] where catastrophizing was significantly correlated with both pain intensity and disability in patients with idiopathic chronic neck pain. The most of these studies provide evidence about the association between the psychological compromise of chronic neck pain patients and their pain and disabil-
ity by examining each psychological factor in isolation. This fact may lead to an overconsideration of the contribution of each psychological factor to the explanation of pain intensity and disability [15,16]. Furthermore, very rarely the population under examination was consisted of only patients with idiopathic chronic neck pain. This fact can significantly affect the external validity of the findings when the conclusions are aimed at being generalized in patients with idiopathic chronic neck pain. Finally, the results are conflicting and highlight the need for further examination of these psychological states in patients with idiopathic chronic neck pain. The recognition of the psychological states which are connected to neck pain and disability of these patients could lead to the identification of important therapeutic markers for clinical practice. The aim of this study was to investigate the association between psychological states of idiopathic chronic neck pain patients (anxiety, depression, kinesiophobia, catastrophizing) with their neck pain intensity and disability. A secondary aim was to examine the relative importance of each psychological factor for predicting pain and disability.
2. Methods 2.1. Subjects Data was obtained from an existing cross-sectional study in 45 patients with idiopathic chronic neck pain [17]. They were patients with idiopathic chronic neck pain of more than six months and with pain complaints of at least once a week. Eligibility criteria and demographics are analytically described in the same publication [17]. In short, it was a middle-aged (age: 35.9 ± 14.5 years) group of patients with chronic neck pain. The sample was consisted mostly of females (13 males, 32 females) and reported to have mild to moderate neck pain intensity and mild disability (Visual Analogue scale: 45.5 ± 18.8 cm, Neck Disability Index: 10.6 ± 5.2). The measurements were performed at the Physiotherapy Department, Technological Educational Institute (TEI) of Lamia, Greece during the period 2009–2010. Patients could participate after reading an information sheet and signing a consent form. The study was approved by the Ethics Committee of the Department of Physiotherapy, School of Health and Caring Professions, TEI Lamia, Greece and the University of Manchester Ethics Committee.
Z. Dimitriadis et al. / Do psychological states associate with pain and disability in chronic neck pain patients?
2.2. Questionnaires The scales and questionnaires used for the study have been described previously [17,18]. Pain intensity was assessed by using a Visual Analogue Scale (VAS) [19]. Disability was assessed by using the Neck Disability Index (NDI) [20]. Psychological states of patients were recorded by using the Hospital Anxiety and Depression Scale (HADS) [21], the Tampa Scale for Kinesiophobia (TSK) [22] and the Pain Catastrophizing Scale [23]. The HADS is a 14-item questionnaire with two subscales (anxiety and depression). The score of each subscale can range from 0 to 21. High scores represent high levels of anxiety or depression. The TSK is a 17-item instrument. The total score may vary from 17 to 68. High scores represent high levels of Kinesiophobia. The PCS contains 13-items. The total score of the questionnaire may range from 0 to 52. High scores suggest high levels of catastrophizing. These instruments have been translated in Greek language and validated in Greek population [24–27]. 2.3. Statistical analysis Correlations between psychological states (anxiety, depression, kinesiophobia, catastrophizing) and neck pain intensity and disability were examined by using Pearson correlation coefficients. Multiple regression analysis (forced enter method) was used for examining the relative contribution of each psychological predictor to pain intensity and disability. These predictors were selected to be the anxiety, depression, kinesiophobia and catastrophizing of patients with chronic neck pain. Correlations of P < 0.05 were considered as statistically significant. All the analysis was performed with the Statistical Package of Social Sciences, version 17.0.
3. Results Neck pain intensity was significantly correlated with anxiety (r = 0.32, p < 0.05). NDI was significantly correlated with anxiety (r = 0.54, p < 0.001), depression (r = 0.32, p < 0.05) and catastrophizing (r = 0.58, p < 0.001). Neck pain intensity was significantly correlated with NDI (r = 0.35, p < 0.05). Pain intensity and NDI were not significantly correlated with other psychological states (r < 0.3, p > 0.05) (Table 1). The constructed model for the prediction of pain intensity was not a significantly fit of the data overall
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Table 1 Correlations between psychological states of patients with chronic neck pain with their self-reported pain and disability Anxiety Depression Catastrophizing Kinesiophobia
Pain intensity 0.32∗ −0.04 0.25 0.16
Disability 0.54∗∗∗ 0.32∗ 0.58∗∗∗ 0.19
The table presents the Pearson correlation coefficients. ∗ p < 0.05, ∗∗ p < 0.01, ∗∗∗ p < 0.001.
(p > 0.05). The multiple correlation coefficient was moderate (R = 0.41, R2 = 0.16, adjusted R2 = 0.08). There were no concerns with multicollinearity (tolerance > 0.55). The model met the criteria of independent errors (Durbin-Watson = 1.89), homoscedasticity and linearity (plot of standardized residuals against standardized predicted values) and normally distributed errors (histogram with a superimposed normal curve). The analysis did not reveal any psychological state as significant predictor (Table 2). The constructed model for the prediction of disability was a significantly fit of the data overall (p < 0.05). The multiple correlation coefficient was satisfactory (R = 0.65, R2 = 0.43, adjusted R2 = 0.37). There were no concerns with multicollinearity (tolerance > 0.55). The model met the criteria of independent errors (Durbin-Watson = 2.16), homoscedasticity and linearity (plot of standardized residuals against standardized predicted values) and normally distributed errors (histogram with a superimposed normal curve). Anxiety and catastrophizing were revealed as significant psychological predictors of disability (Table 2).
4. Discussion According to the results of the current study, neck pain intensity is associated with anxiety whereas disability is associated with anxiety, depression and catastrophizing. Regression analysis revealed that none of the examined psychological factors can significantly predict pain intensity. An interesting finding of the study was that disability can be significantly predicted by anxiety and catastrophizing. Literature recognizes anxiety as an important psychological factor associated with pain and disability [7,8]. The findings of the present study confirm the findings of previous studies which report a significant association of anxiety with either neck pain intensity [7] or self-reported disability [8]. The effect sizes of these associations were found to be higher that the previously performed studies [7] something which
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Z. Dimitriadis et al. / Do psychological states associate with pain and disability in chronic neck pain patients? Table 2 Multiple regression analysis for patients with chronic neck pain (n = 45) Pain prediction Constant Anxiety Depression Catastrophizing Kinesiophobia Disability prediction Constant Anxiety Depression Catastrophizing Kinesiophobia
Part r
B
SE B
β
p
− 0.26 −0.23 0.14 0.02
32.2 1.33 −1.34 0.3 0.06
13.9 0.75 0.83 0.31 0.46
− 0.32 −0.27 0.19 0.02
0.026 0.08 0.12 0.34 0.90
− 0.27 0.02 0.36 −0.16
7.4 0.39 0.02 0.21 −0.14
3.16 0.17 0.19 0.07 0.11
− 0.34 0.02 0.48 −0.19
0.024 0.028 0.90 0.005 0.20
The table presents the part correlation of each predictor (Part r), the beta values (B), the standard error of B (SE B) and the standardized beta values (β) for the prediction of neck pain and disability.
might be partially attributed to the better homogeneity of the sample used in the current study as all the patients were suffering from idiopathic chronic neck pain. Furthermore, anxiety was the only psychological state which was found to be significantly correlated with both neck pain intensity and disability. Its high unique correlation with self-reported disability also led to its recognition as one of its most significant predictors. Literature has provided physiological explanations about the connection of anxiety with pain experience and disability. Anxiety may lead to a change of the reticular activity increasing the supraspinal transmission of nociceptive signals. Moreover, anxiety is associated with increase in the levels of adrenaline. Adrenaline release can lead to stimulation of β2receptors leading to a pro-inflammatory cascade of events with a consequential increase of pain experience. Furthermore, it is believed that anxiety affects the autonomous nervous system resulting in vasoconstriction of some muscle areas and promoting muscle injury. Anxiety is also supported to influence vessels and muscles via the central nervous system due to its association with their function [4]. Conversely, the existence of neck pain by itself may lead the sufferers to higher levels of discomfort and stress [28]. Anxiety seems to be one key psychological factor leading patients with chronic neck pain to increased pain experience and disability. Depression was also found to be associated with greater disability. This comes in agreement with other studies [8]. However, it seems that this association becomes less important when it is considered in parallel with other psychological states. Furthermore, the association between depression and pain that is partially supported by other studies [3,10,11] was not confirmed
in this study. The reason for this inconsistency may be that neither of these studies has recruited a group of patients solely with idiopathic chronic neck pain and that the study designs used were different from the current study. Moreover, the sample of patients used in this study was of mild neck pain and disability which might have not led them to considerable depression. Physiologically, depression is also considered a psychological state increasing the pain experience via a reduction of the activity of descending inhibitory pathways. Furthermore, increase in pain experience may arrive in a way similar to anxiety as autonomous nervous system has been also hypothesized to be affected by depression resulting in vasoconstriction and promoting muscle injury [4]. However, its association with the pain experienced by the sample used in this study seems to be less important. Kinesiophobia was not found to be associated with pain or disability. This finding is in contrast to the initial beliefs that kinesiophobia would be one of the most important psychological states of patients with chronic neck pain and that it would be highly associated with pain and disability. Based on physiology, phobia is associated with release of adrenaline [29] and therefore kinesiophobia may lead to increased pain perception in a way similar to anxiety. Kinesiophobia can also lead patients to avoid movement, exercises or activities due to fear of pain or re-injury. This maladaptive response can lead to increase of pain perception, physiological consequences such as fibrosis and atrophy due to immobility and finally to prolonged disability [13,14]. Kinesiophobia is believed to be one of the most important factors for the transition from acute to chronic pain and disability [30,31]. Similar are the beliefs for patients with chronic neck pain although the results are conflicting [2,9]. However, sim-
Z. Dimitriadis et al. / Do psychological states associate with pain and disability in chronic neck pain patients?
ilarly to the study by Thompson et al. [15], the current findings did not reveal any significant association of kinesiophobia with pain and disability. These findings may be attributed to the fact that both studies recruited patients with idiopathic neck pain as in patients with whiplash-associated disorders these associations are significantly stronger [16]. The lack of a traumatic history might alter the kinesiophobic thoughts of patients and the way they react to fear and therefore the connection of kinesiophobia with pain and disability. Catastrophizing was found to be significantly associated with pain-induced disability still when the effects of the other psychological parameters were controlled. This association is also supported by previous studies where a similar sample of patients was used [2,15]. Catastrophizing may lead to more intense pain experience and increased emotional distress. The real reason for this psychological state is not absolutely understood and it is usually viewed as a cognitive distortion, belief, appraisal process, attentional process or coping strategy. Catastrophizing is believed to be associated with pain and disability due to a link with the action of opiates, activation of pain anticipation regions of the brain or amplification of the peripheral signals in response to subsequent pain [5]. Interestingly, the psychological states of patients with idiopathic chronic neck pain were mostly associated with their disability rather that their pain intensity. Similar conclusions derive from the study by Thompson et al. [15] as psychological states of patients with idiopathic chronic neck pain presented stronger associations with disability than pain intensity. This fact might reveal that changes of the psychological states of patients with idiopathic chronic neck pain may have a stronger impact on their disability without significantly altering their pain intensity. This potentially highlights that the psychological compromise of patients with idiopathic chronic neck pain may be responsible in a great extent for the disability reported. This disability might be partially a maladaptive strategy which in a great extent is attributed to patients’ beliefs. This fact may also explain the importance of catastrophizing for predicting patients’ disability something which is also depicted to the fact that pain disability presented a lower correlation with pain intensity than the correlation it presented with catastrophizing. The findings of the study provide important clinical implications for health scientists and psychologists. Anxiety and catastrophizing have been revealed to be two important psychological states that should be targeted during rehabilitation. Cognitive-behavioral in-
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terventions as adjacent to conventional physiotherapy might lead to decreased levels of pain and especially disability. Graded exposure and graded activity have been already suggested by Thompson et al. [15,16] as potentially helpful approaches to reduce catastrophizing [32]. Relaxation techniques might be also helpful for decreasing anxiety [33]. Therefore, patients are suggested to be advised not to restrain from daily activities and exercises. Instead they should continue their activities and their disorder-specific exercises, maintain their social participation and finally gradely return to the activities they avoided. Despite the important findings of this study there are certain limitations that should be taken into consideration. The cross-sectional design does not allow for establishing a cause-effect relationship. This means that the relationships detected in this study may be bidirectional [34]. Furthermore, the sample recruitment was not based on a random method, but was conveniently performed. This fact means that the results are prone to involuntary selection bias. However, the random selection of participants was not possible because the data of the study was based on a previous study with very strict eligibility criteria [17].
5. Conclusion In conclusion, patients with chronic neck pain experience psychological states which are associated with their pain and disability. Anxiety, catastrophizing and depression seem to the psychological states which are mostly associated with the self-reported disability, whereas anxiety is also associated with pain intensity of patients with idiopathic chronic neck pain. The fact that the disability experienced by these patients presents a stronger association with these psychological states in comparison with the same correlations of pain intensity, lead to the conclusion that this disability might be the result of the psychological status of these patients rather that a direct result of their pain. Thus, future clinical studies are advised to examine the effectiveness of cognitive and behavioural rehabilitation strategies as an adjunct to the usual treatment protocols of these patients.
Acknowledgements We would like to thank the participants for their willingness to participate in this study and Ms Lamprini Komnianou for technical assistance.
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Conflict of interest There are no known conflicts of interest.
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Journal of Back and Musculoskeletal Rehabilitation 28 (2015) 797–802 DOI 10.3233/BMR-150587 IOS Press
Do psychological states associate with pain and disability in chronic neck pain patients? Zacharias Dimitriadisa,b,∗ , Eleni Kaprelia , Nikolaos Strimpakosa,b and Jacqueline Oldhamb a
b
Physiotherapy Department, T.E.I. of Lamia, Lamia, Greece Manchester Academic Health Sciences Centre, University of Manchester, Manchester, UK
Abstract. BACKGROUND: Chronic neck pain is one of the most usual neuromusculoskeletal pain conditions which can lead patients to chronic disability. Similarly to other pain conditions, the changed psychological status of these patients is believed to be associated with their pain condition and disability. However, the association between the psychological status of patients with idiopathic neck pain and their pain intensity and disability is minimally explored. OBJECTIVE: This study was aimed at investigating the association between psychological states (anxiety, depression, kinesiophobia, catastrophizing) of patients with chronic idiopathic neck pain and self-reported pain and disability. METHODS: Forty five patients with idiopathic chronic neck pain (more than 6 months, at least once a week) participated. Their psychological states were assessed by using the Hospital Anxiety and Depression scale, Pain Catastrophizing scale and Tampa Scale for Kinesiophobia. Self-reported disability was recorded with the Neck Disability Index. Pain intensity was recorded by using a visual analog scale. RESULTS: Neck pain intensity was significantly correlated with anxiety (p < 0.05). Disability was significantly correlated with anxiety, depression and catastrophizing (p < 0.05). Multiple regression analysis showed that pain-induced disability can be significantly predicted by anxiety and catastrophizing (p < 0.05). CONCLUSIONS: It can be concluded that anxiety, depression and catastrophizing of patients with chronic neck pain is associated with their self-reported disability, whereas anxiety is also associated with their pain intensity. Anxiety and catastrophizing may be important predicting markers of patients’ self-reported disability. Keywords: Anxiety, catastrophizing, neck pain, depression, kinesiophobia
1. Introduction Cervical spine studies have shown that chronic neck pain is associated with psychological states such as anxiety, depression, kinesiophobia and catastrophizing [1–3]. These psychological states are believed to lead to a biochemical sequence of events leading to experience of greater pain and disability [4,5]. The same psychological states can also indirectly deteriorate patients’ symptoms due to movement and exercise avoidance or restraining from daily activities [5,6]. These ∗ Corresponding author: Zacharias Dimitriadis, TEI Lamia, Department of Physiotherapy, 3rd km O.N.R. Lamia-Athens, 35100, Lamia, Greece. E-mail: [email protected].
facts reveal that psychologically compromised patients with chronic neck pain may have a more excruciated experience of their condition. The connection of psychological influences of neck pain with pain intensity and disability is a point of interest in many observational studies. However, in patients with idiopathic chronic neck pain the findings are limited and conflicting. Anxiety is one of the most important psychological states that are believed to be associated with the existence of higher levels of pain and disability in musculoskeletal pain conditions. Bru et al. [7] found that anxiety presents a weak correlation with pain intensity. Additionally, Luo et al. [8] recruited a sample comprised mainly of patients with idiopathic chronic neck pain and found that anxiety presents a similar associ-
c 2015 – IOS Press and the authors. All rights reserved ISSN 1053-8127/15/$35.00
798
Z. Dimitriadis et al. / Do psychological states associate with pain and disability in chronic neck pain patients?
ation with neck pain disability. Leino and Magni [1] found that the existence of stress symptoms is a significant marker for the development of neck/shoulder pain 5 years after the initial assessment. Depression also seems to be correlated with neck pain and disability although the findings of different studies are not consistent with each other. Luo et al. [8] observed a weak correlation between depression and neck pain disability. In a study by Pool et al. [9] it was found that the depression of neck pain patients cannot predict their recovery. Contrastingly, Mantyselka et al. [3] found that the daily neck pain is a significant predictor of depression. Another study by Rajala et al. [10] also shows that neck pain is frequently observed among depressed individuals. Furthermore, Leino and Magni [1] and Rajala et al. [10] found that the appearance of neck pain can be predicted by depression, whereas a correlation between depression and shoulder/neck pain was also observed by Pollock et al. [11]. Movement avoidance due to fear of pain or re-injury is also considered an important factor for prolonged pain and disability [12]. Kinesiophobia has been found to be associated and to be able to predict chronic neck pain disability [13,14]. Additionally, Pool et al. [9] found that the recovery of patients with sub-acute neck pain can be impeded by kinesiophobia. Although these findings are in contrast with the findings by Hill et al. [2], an association of kinesiophobia with recovery after physiotherapy was also observed. Finally, Thompson et al. [15] did not find any association between kinesiophobia and pain and disability in a sample of patients exclusively with idiopathic chronic neck pain. Catastrophizing is a psychological factor that is also related with increased experience of pain and disability [5]. A study by Pool et al. [9], in a sample of patients with sub-acute whiplash or idiopathic neck pain, shows that the recovery of patients after rehabilitation cannot be predicted by catastrophizing. In contrast, in another study by Hill et al. [2] in patients with nonspecific neck pain, catastrophizing was found to be an important factor for the prediction of recovery of patients after physiotherapy. This association is also highlighted in a study by Thompson et al. [15] where catastrophizing was significantly correlated with both pain intensity and disability in patients with idiopathic chronic neck pain. The most of these studies provide evidence about the association between the psychological compromise of chronic neck pain patients and their pain and disabil-
ity by examining each psychological factor in isolation. This fact may lead to an overconsideration of the contribution of each psychological factor to the explanation of pain intensity and disability [15,16]. Furthermore, very rarely the population under examination was consisted of only patients with idiopathic chronic neck pain. This fact can significantly affect the external validity of the findings when the conclusions are aimed at being generalized in patients with idiopathic chronic neck pain. Finally, the results are conflicting and highlight the need for further examination of these psychological states in patients with idiopathic chronic neck pain. The recognition of the psychological states which are connected to neck pain and disability of these patients could lead to the identification of important therapeutic markers for clinical practice. The aim of this study was to investigate the association between psychological states of idiopathic chronic neck pain patients (anxiety, depression, kinesiophobia, catastrophizing) with their neck pain intensity and disability. A secondary aim was to examine the relative importance of each psychological factor for predicting pain and disability.
2. Methods 2.1. Subjects Data was obtained from an existing cross-sectional study in 45 patients with idiopathic chronic neck pain [17]. They were patients with idiopathic chronic neck pain of more than six months and with pain complaints of at least once a week. Eligibility criteria and demographics are analytically described in the same publication [17]. In short, it was a middle-aged (age: 35.9 ± 14.5 years) group of patients with chronic neck pain. The sample was consisted mostly of females (13 males, 32 females) and reported to have mild to moderate neck pain intensity and mild disability (Visual Analogue scale: 45.5 ± 18.8 cm, Neck Disability Index: 10.6 ± 5.2). The measurements were performed at the Physiotherapy Department, Technological Educational Institute (TEI) of Lamia, Greece during the period 2009–2010. Patients could participate after reading an information sheet and signing a consent form. The study was approved by the Ethics Committee of the Department of Physiotherapy, School of Health and Caring Professions, TEI Lamia, Greece and the University of Manchester Ethics Committee.
Z. Dimitriadis et al. / Do psychological states associate with pain and disability in chronic neck pain patients?
2.2. Questionnaires The scales and questionnaires used for the study have been described previously [17,18]. Pain intensity was assessed by using a Visual Analogue Scale (VAS) [19]. Disability was assessed by using the Neck Disability Index (NDI) [20]. Psychological states of patients were recorded by using the Hospital Anxiety and Depression Scale (HADS) [21], the Tampa Scale for Kinesiophobia (TSK) [22] and the Pain Catastrophizing Scale [23]. The HADS is a 14-item questionnaire with two subscales (anxiety and depression). The score of each subscale can range from 0 to 21. High scores represent high levels of anxiety or depression. The TSK is a 17-item instrument. The total score may vary from 17 to 68. High scores represent high levels of Kinesiophobia. The PCS contains 13-items. The total score of the questionnaire may range from 0 to 52. High scores suggest high levels of catastrophizing. These instruments have been translated in Greek language and validated in Greek population [24–27]. 2.3. Statistical analysis Correlations between psychological states (anxiety, depression, kinesiophobia, catastrophizing) and neck pain intensity and disability were examined by using Pearson correlation coefficients. Multiple regression analysis (forced enter method) was used for examining the relative contribution of each psychological predictor to pain intensity and disability. These predictors were selected to be the anxiety, depression, kinesiophobia and catastrophizing of patients with chronic neck pain. Correlations of P < 0.05 were considered as statistically significant. All the analysis was performed with the Statistical Package of Social Sciences, version 17.0.
3. Results Neck pain intensity was significantly correlated with anxiety (r = 0.32, p < 0.05). NDI was significantly correlated with anxiety (r = 0.54, p < 0.001), depression (r = 0.32, p < 0.05) and catastrophizing (r = 0.58, p < 0.001). Neck pain intensity was significantly correlated with NDI (r = 0.35, p < 0.05). Pain intensity and NDI were not significantly correlated with other psychological states (r < 0.3, p > 0.05) (Table 1). The constructed model for the prediction of pain intensity was not a significantly fit of the data overall
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Table 1 Correlations between psychological states of patients with chronic neck pain with their self-reported pain and disability Anxiety Depression Catastrophizing Kinesiophobia
Pain intensity 0.32∗ −0.04 0.25 0.16
Disability 0.54∗∗∗ 0.32∗ 0.58∗∗∗ 0.19
The table presents the Pearson correlation coefficients. ∗ p < 0.05, ∗∗ p < 0.01, ∗∗∗ p < 0.001.
(p > 0.05). The multiple correlation coefficient was moderate (R = 0.41, R2 = 0.16, adjusted R2 = 0.08). There were no concerns with multicollinearity (tolerance > 0.55). The model met the criteria of independent errors (Durbin-Watson = 1.89), homoscedasticity and linearity (plot of standardized residuals against standardized predicted values) and normally distributed errors (histogram with a superimposed normal curve). The analysis did not reveal any psychological state as significant predictor (Table 2). The constructed model for the prediction of disability was a significantly fit of the data overall (p < 0.05). The multiple correlation coefficient was satisfactory (R = 0.65, R2 = 0.43, adjusted R2 = 0.37). There were no concerns with multicollinearity (tolerance > 0.55). The model met the criteria of independent errors (Durbin-Watson = 2.16), homoscedasticity and linearity (plot of standardized residuals against standardized predicted values) and normally distributed errors (histogram with a superimposed normal curve). Anxiety and catastrophizing were revealed as significant psychological predictors of disability (Table 2).
4. Discussion According to the results of the current study, neck pain intensity is associated with anxiety whereas disability is associated with anxiety, depression and catastrophizing. Regression analysis revealed that none of the examined psychological factors can significantly predict pain intensity. An interesting finding of the study was that disability can be significantly predicted by anxiety and catastrophizing. Literature recognizes anxiety as an important psychological factor associated with pain and disability [7,8]. The findings of the present study confirm the findings of previous studies which report a significant association of anxiety with either neck pain intensity [7] or self-reported disability [8]. The effect sizes of these associations were found to be higher that the previously performed studies [7] something which
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Z. Dimitriadis et al. / Do psychological states associate with pain and disability in chronic neck pain patients? Table 2 Multiple regression analysis for patients with chronic neck pain (n = 45) Pain prediction Constant Anxiety Depression Catastrophizing Kinesiophobia Disability prediction Constant Anxiety Depression Catastrophizing Kinesiophobia
Part r
B
SE B
β
p
− 0.26 −0.23 0.14 0.02
32.2 1.33 −1.34 0.3 0.06
13.9 0.75 0.83 0.31 0.46
− 0.32 −0.27 0.19 0.02
0.026 0.08 0.12 0.34 0.90
− 0.27 0.02 0.36 −0.16
7.4 0.39 0.02 0.21 −0.14
3.16 0.17 0.19 0.07 0.11
− 0.34 0.02 0.48 −0.19
0.024 0.028 0.90 0.005 0.20
The table presents the part correlation of each predictor (Part r), the beta values (B), the standard error of B (SE B) and the standardized beta values (β) for the prediction of neck pain and disability.
might be partially attributed to the better homogeneity of the sample used in the current study as all the patients were suffering from idiopathic chronic neck pain. Furthermore, anxiety was the only psychological state which was found to be significantly correlated with both neck pain intensity and disability. Its high unique correlation with self-reported disability also led to its recognition as one of its most significant predictors. Literature has provided physiological explanations about the connection of anxiety with pain experience and disability. Anxiety may lead to a change of the reticular activity increasing the supraspinal transmission of nociceptive signals. Moreover, anxiety is associated with increase in the levels of adrenaline. Adrenaline release can lead to stimulation of β2receptors leading to a pro-inflammatory cascade of events with a consequential increase of pain experience. Furthermore, it is believed that anxiety affects the autonomous nervous system resulting in vasoconstriction of some muscle areas and promoting muscle injury. Anxiety is also supported to influence vessels and muscles via the central nervous system due to its association with their function [4]. Conversely, the existence of neck pain by itself may lead the sufferers to higher levels of discomfort and stress [28]. Anxiety seems to be one key psychological factor leading patients with chronic neck pain to increased pain experience and disability. Depression was also found to be associated with greater disability. This comes in agreement with other studies [8]. However, it seems that this association becomes less important when it is considered in parallel with other psychological states. Furthermore, the association between depression and pain that is partially supported by other studies [3,10,11] was not confirmed
in this study. The reason for this inconsistency may be that neither of these studies has recruited a group of patients solely with idiopathic chronic neck pain and that the study designs used were different from the current study. Moreover, the sample of patients used in this study was of mild neck pain and disability which might have not led them to considerable depression. Physiologically, depression is also considered a psychological state increasing the pain experience via a reduction of the activity of descending inhibitory pathways. Furthermore, increase in pain experience may arrive in a way similar to anxiety as autonomous nervous system has been also hypothesized to be affected by depression resulting in vasoconstriction and promoting muscle injury [4]. However, its association with the pain experienced by the sample used in this study seems to be less important. Kinesiophobia was not found to be associated with pain or disability. This finding is in contrast to the initial beliefs that kinesiophobia would be one of the most important psychological states of patients with chronic neck pain and that it would be highly associated with pain and disability. Based on physiology, phobia is associated with release of adrenaline [29] and therefore kinesiophobia may lead to increased pain perception in a way similar to anxiety. Kinesiophobia can also lead patients to avoid movement, exercises or activities due to fear of pain or re-injury. This maladaptive response can lead to increase of pain perception, physiological consequences such as fibrosis and atrophy due to immobility and finally to prolonged disability [13,14]. Kinesiophobia is believed to be one of the most important factors for the transition from acute to chronic pain and disability [30,31]. Similar are the beliefs for patients with chronic neck pain although the results are conflicting [2,9]. However, sim-
Z. Dimitriadis et al. / Do psychological states associate with pain and disability in chronic neck pain patients?
ilarly to the study by Thompson et al. [15], the current findings did not reveal any significant association of kinesiophobia with pain and disability. These findings may be attributed to the fact that both studies recruited patients with idiopathic neck pain as in patients with whiplash-associated disorders these associations are significantly stronger [16]. The lack of a traumatic history might alter the kinesiophobic thoughts of patients and the way they react to fear and therefore the connection of kinesiophobia with pain and disability. Catastrophizing was found to be significantly associated with pain-induced disability still when the effects of the other psychological parameters were controlled. This association is also supported by previous studies where a similar sample of patients was used [2,15]. Catastrophizing may lead to more intense pain experience and increased emotional distress. The real reason for this psychological state is not absolutely understood and it is usually viewed as a cognitive distortion, belief, appraisal process, attentional process or coping strategy. Catastrophizing is believed to be associated with pain and disability due to a link with the action of opiates, activation of pain anticipation regions of the brain or amplification of the peripheral signals in response to subsequent pain [5]. Interestingly, the psychological states of patients with idiopathic chronic neck pain were mostly associated with their disability rather that their pain intensity. Similar conclusions derive from the study by Thompson et al. [15] as psychological states of patients with idiopathic chronic neck pain presented stronger associations with disability than pain intensity. This fact might reveal that changes of the psychological states of patients with idiopathic chronic neck pain may have a stronger impact on their disability without significantly altering their pain intensity. This potentially highlights that the psychological compromise of patients with idiopathic chronic neck pain may be responsible in a great extent for the disability reported. This disability might be partially a maladaptive strategy which in a great extent is attributed to patients’ beliefs. This fact may also explain the importance of catastrophizing for predicting patients’ disability something which is also depicted to the fact that pain disability presented a lower correlation with pain intensity than the correlation it presented with catastrophizing. The findings of the study provide important clinical implications for health scientists and psychologists. Anxiety and catastrophizing have been revealed to be two important psychological states that should be targeted during rehabilitation. Cognitive-behavioral in-
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terventions as adjacent to conventional physiotherapy might lead to decreased levels of pain and especially disability. Graded exposure and graded activity have been already suggested by Thompson et al. [15,16] as potentially helpful approaches to reduce catastrophizing [32]. Relaxation techniques might be also helpful for decreasing anxiety [33]. Therefore, patients are suggested to be advised not to restrain from daily activities and exercises. Instead they should continue their activities and their disorder-specific exercises, maintain their social participation and finally gradely return to the activities they avoided. Despite the important findings of this study there are certain limitations that should be taken into consideration. The cross-sectional design does not allow for establishing a cause-effect relationship. This means that the relationships detected in this study may be bidirectional [34]. Furthermore, the sample recruitment was not based on a random method, but was conveniently performed. This fact means that the results are prone to involuntary selection bias. However, the random selection of participants was not possible because the data of the study was based on a previous study with very strict eligibility criteria [17].
5. Conclusion In conclusion, patients with chronic neck pain experience psychological states which are associated with their pain and disability. Anxiety, catastrophizing and depression seem to the psychological states which are mostly associated with the self-reported disability, whereas anxiety is also associated with pain intensity of patients with idiopathic chronic neck pain. The fact that the disability experienced by these patients presents a stronger association with these psychological states in comparison with the same correlations of pain intensity, lead to the conclusion that this disability might be the result of the psychological status of these patients rather that a direct result of their pain. Thus, future clinical studies are advised to examine the effectiveness of cognitive and behavioural rehabilitation strategies as an adjunct to the usual treatment protocols of these patients.
Acknowledgements We would like to thank the participants for their willingness to participate in this study and Ms Lamprini Komnianou for technical assistance.
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Conflict of interest There are no known conflicts of interest.
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