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SCIENTIFIC LETTER
Medically unexplained dyspnoea and panic ROSE HAUZER,1 WILLEKE VERHEUL,2 ERIC GRIEZ,1 GEERTJAN WESSELING3 AND MARLIES van DUINEN1 Departments of 1Psychiatry and Neuropsychology and 3Respiratory Medicine, Maastricht University, Maastricht, and 2 Department of Psychiatry, Medisch Spectrum Twente, Enschede, The Netherlands
Medically unexplained dyspnoea in the pulmonary setting is often accompanied by considerable levels of anxiety, suggestive of psychopathology, in particular panic disorder (PD). This pilot study investigates the value of the Multidimensional Dyspnea Profile as a tool to facilitate identification of a specific dyspnoea profile suggestive of comorbid PD. The verbal descriptors, feeling depressed, air hunger and concentrating on breathing, significantly differentiated between the two groups of patients with pulmonary disease with and without PD. Key words: chronic lung disease, depressed affect, medically unexplained dyspnoea, Multidimensional Dyspnea Profile, panic disorder. Abbreviations: BMI, body mass index; COPD, chronic obstructive pulmonary disease; MDP, Multidimensional Dyspnea Profile; MUD, medically unexplained dyspnoea; PD, panic disorder; PulnonPD, chronic obstructive pulmonary disease/asthma without panic disorder; PulPD, chronic obstructive pulmonary disease/asthma with panic disorder.
Medically unexplained dyspnoea (MUD) in patients with pulmonary disease leads to considerable use of medical resources and diminished quality of life. MUD patients often present with increased levels of anxiety. MUD and anxiety disorders, in particular panic disorder (PD) have frequently been reported to coexist.1,2 MUD and PD disorders show respiratory symptomatology, with dyspnoea as a core symptom. Dyspnoea is described as the subjective experience of breathing discomfort that subsumes qualitatively distinct sensations with variable intensity.3 The experience of dyspnoea is based on complex interactions of multiple physiological, psychological, social and environmental factors.4 Subtyping of dyspnoea profiles in MUD patients can provide more detailed information on the nature of the complaints, which could facilitate tailored treatment strategies. Correspondence: Marlies van Duinen, Department of Psychiatry and Neuropsychology, Maastricht University, Universiteitssingel 50, PO Box 88, 6200 AB, Maastricht, The Netherlands. Email: [email protected] Received 4 September 2014; invited to revise 10 October 2014; revised 5 January 2015; accepted 21 January 2015 (Associate Editor: Melissa Benton) Article first published online: 30 March 2015 © 2015 Asian Pacific Society of Respirology
The aim of this pilot study is to find dyspnoea modalities using the Multidimensional Dyspnea Profile (MDP) to describe dyspnoea profiles in patients with pulmonary disease with and without PD.5 Fifty-eight patients (36 females/22 males) with confirmed pulmonary disease with dyspnoea, which severity could not be explained by pulmonary physiological parameters, were recruited from the pulmonary outpatient clinic of the university hospital of Maastricht. Mean age was 63.8 ± 9.1 years, mean body mass index (BMI) 27.6 ± 4.7 and mean Tiffeneau index 57.3 ± 18.3 (chronic obstructive pulmonary disease (COPD) only). Forty-three (24 females/19 males) PD patients without documented respiratory disorder were recruited as controls from an academic psychiatric outpatient clinic in Maastricht (mean age: 38.4 ± 12.2 years). The local medical ethics committee approved the study, and written informed consent was obtained from all participants. Intensity of dyspnoea modalities during an episode of breathlessness was assessed retrospectively with the MDP during stable respiratory phase. The MDP is a validated tool used in the pulmonary setting that delineates both sensory and affective dimensions.5,6 The MDP incorporates 0–10 point rating scales (10 = most severe I can imagine) including five sensory descriptors and seven affective descriptors of dyspnoea. An overall descriptor describing the level of unpleasantness was also evaluated on a 0–10 point scale. A psychiatric diagnosis was made according to the Dutch version of the Mini-International Neuropsychiatric Interview according to Diagnostic and Statistical Manual of Mental Disorders-IV7 complemented with expert clinical opinion en peer consensus. Statistical analyses were performed using nonparametric tests (SPSS 17.0 for Windows, SPSS Inc., Chicago, IL, USA). Between-group comparisons for the three diagnostic groups were performed using the Kruskal–Wallis test for individual MDP items. Posthoc testing using the Mann–Whitney U-test compared patients with pulmonary disease and PD (COPD/asthma with panic disorder (PulPD) group) with patients with pulmonary disease without Respirology (2015) 20, 828–830 doi: 10.1111/resp.12516
Medically unexplained dyspnoea and panic
comorbid PD (COPD/asthma without panic disorder (PulnonPD) group). The group of patients with pulmonary disease and MUD consisted of COPD patients (n = 45) and asthma patients (n = 13). Twenty-three patients were diagnosed with PD: 17 COPD and 6 asthma patients. In total, 35 of the 58 interviewed pulmonary patients had a coexisting psychiatric diagnosis including major depression, dysthymic disorder, PD, agoraphobia, specific phobia, obsessive compulsive disorder and generalized anxiety disorder. Twenty-one of these patients had more than one psychiatric diagnosis. There were no significant differences between the PulPD and the PulnonPD group in age, gender, BMI and the presence of comorbid depression. The PD control group was significantly younger compared with the groups with pulmonary pathology. The Mann–Whitney U-test showed statistically significant differences between the PulPD group and the PulnonPD group on some MDP items. The PulPD group showed higher scores on the affective dimension ‘depressed’ (P = 0.041), and on the sensory dimensions ‘air hunger’ (P = 0.013) and ‘concentration’ (P = 0.032). Trends were discovered for the affective measures ‘afraid’ (P = 0.065) and ‘constriction’ (P = 0.073). Figure 1 shows MDP values for the different groups. The aim of this pilot study was to describe different profiles of the MDP in identifying PD in MUD patients with lung pathology. The study demonstrates that in 40% of the cases, MUD could be accounted for by comorbid PD. Assessment of the qualities and intensities of ‘unpleasantness’ and the sensory and affective dimensions of dyspnoea in MUD demonstrated significantly higher scores in PulPD patients within the sensory dimension, on the items ‘air hunger’ and ‘concentrating on breathing’. With regard to the affective dimension, the PD and PulPD reported increased depressive feelings, which was the most pronounced difference between the PulPD and PulnonPD group. This difference was not accounted for by the diagnosis of depression. The experience of pure non-organic dyspnoea, that is panic attack, shows a similar intensity on the sensory quality of ‘air hunger’ as pure organic dyspnoea, underlining the difficulty to identify the cause of dyspnoea in a clinical setting. Even though the absolute difference in score of one point was statistically significant, this is of limited clinical relevance. In addition to biological hypersensitivity to fluctuations in CO2 levels, cognitive models explain a sensitized perception of air hunger by creating a positive feedback loop in PD.8–10 In patients with respiratory impairment and PD, physical exertion can precipitate the perception of threat and anxiety. This triggers physiological arousal, leading to escalating cognitions and recurrent, reinforced depressive feelings. This confirms the earlier finding that depressive symptoms have a strong predictive value.10–12 Concentrating on breathing is a strategy to regain control over the otherwise unconscious process of breathing. In this study, significantly higher scores © 2015 Asian Pacific Society of Respirology
829
Figure 1 Multidimensional Dyspnea Profile (MDP). Median values of the three diagnostic groups are presented for all items. ( ) PulnonPD (chronic obstructive pulmonary disease (COPD)/ asthma without panic disorder; n = 35); ( ) PulPD (COPD/asthma with panic disorder; n = 23); ( ) PD (panic disorder without respiratory disorder; n = 43). *Significance was set at P < 0.05.
were found in PulPD patients and the control PD group for concentrating on breathing, implying an overrepresentation of cognitive compensatory control.13 Scores of PulPD and PulnonPD patients on ‘anxious’, ‘afraid’ and ‘frustration’ during episodes of dyspnoea differed but were statistically comparable. Escalating anxiety in PD is thought to be inhibited in chronic pulmonary patients due to the knowledge of respiratory instability related to structural lung pathology and ascribing failure of compensatory control to inadequate medication prescription. Moreover, adaptation to anxiety and higher CO2 levels might develop in chronic pulmonary patients. In particular, the emotional response of ‘feeling depressed’ and/or ‘concentrating strongly on their breathing’ during dyspnoeic episodes seems to be suggestive of the presence of PD. In order to identify profiles of MDP variables for patients with respiratory disease with or without PD, replication in larger samples is needed. Disruption of respiratory rhythm beyond normal bounds as is seen in dyspnoea is associated with pulmonary disease as well as with PD. This indicates the presence Respirology (2015) 20, 828–830
830 of distinctive dynamics within the respiratory system, leading to separate disease states.14 Describing the intensity of three main variables of the separate disease states (‘air hunger’, ‘depressed affect’ and ‘concentrating on breathing’) and collected serially in real time using a mathematical stochastic model might help to identify chronic pulmonary patients prone to developing comorbid PD at an earlier stage.15 Psychosomatic intervention could be initiated in an early phase with cognitive and/or pharmacologic modification to potentially prevent further disruption of respiratory control and deterioration of illness.
REFERENCES 1 Zandbergen J, Bright M, Pols H, Fernandez I, De Loof C, Griez EJ. Higher lifetime prevalence of respiratory diseases in panic disorder? Am. J. Psychiatry 1991; 148: 1583–5. 2 Han JN, Zhu YJ, Li SW, Luo DM, Hu Z, Van Diest I, De Peuter S, Van de Woestijne KP, Van den Bergh O. Medically unexplained dyspnea: psychophysiological characteristics and role of breathing therapy. Chin. Med. J. 2004; 117: 6–13. 3 Lansing RW, Gracely RH, Banzett RB. The multiple dimensions of dyspnea: review and hypotheses. Respir. Physiol. Neurobiol. 2009; 167: 53–60. 4 Parshall MB, Schwartzstein RM, Adams L, Banzett RB, Manning HL, Bourbeau J, Calverley PM, Gift AG, Harver A, Lareau SC et al. An official American Thoracic Society statement: update on the mechanisms, assessment, and management of dyspnea. Am. J. Respir. Crit. Care Med. 2012; 185: 435–52. 5 Meek PM, Banzett R, Parshall MB, Gracely RH, Schwartzstein RM, Lansing R. Reliability and validity of the multidimensional dyspnea profile. Chest 2012; 141: 1546–53.
Respirology (2015) 20, 828–830
R Hauzer et al. 6 Banzett RB, Pedersen SH, Schwartzstein RM, Lansing RW. The affective dimension of laboratory dyspnea: air hunger is more unpleasant than work/effort. Am. J. Respir. Crit. Care Med. 2008; 177: 1384–90. 7 Sheehan DV, Lecrubier Y, Sheehan KH, Amorim P, Janavs J, Weiller E, Hergueta T, Baker R, Dunbar GC. The MiniInternational Neuropsychiatric Interview (M.I.N.I.): the development and validation of a structured diagnostic psychiatric interview for DSM-IV and ICD-10. J. Clin. Psychiatry 1998; 59(Suppl. 20): 22–33. 8 Colasanti A, Salamon E, Schruers K, Van Diest R, Van Duinen M, Griez E. Carbon dioxide-induced emotion and respiratory symptoms in healthy volunteers. Neuropsychopharmacology 2008; 33: 3103–10. 9 Van Beek N, Griez E. Reactivity to a 35% CO2 challenge in healthy first-degree relatives of patients with panic disorder. Biol. Psychiatry 2000; 47: 830–5. 10 Livermore N, Sharpe L, McKenzie D. Catastrophic interpretations and anxiety sensitivity as predictors of panic-spectrum psychopathology in chronic obstructive pulmonary disease. J. Pychosomatic Research 2012; 72: 388–92. 11 Van Praag HM. Can stress cause depression? Prog. Neuropsychopharmacol Biol. Psychiatry 2004; 28: 891–907. 12 Williams M, Cafarella P, Olds T, Frith PJ. Affective descriptors of the sensation of breathlessness are more highly associated with severity of impairment than physical descriptors in people with COPD. Chest 2010; 138: 315–22. 13 Seth AK. Interoceptive inference, emotion, and the embodied self. Trends Cogn. Sci. 2013; 17: 565–73. 14 Glass L. Synchronization and rhythmic processes in physiology. Nature 2001; 410: 277–84. 15 Van Os J, Delespaul P, Wigman J, Myin-Germeys I, Wichers M. Beyond DSM and ICD: introducing ‘precision diagnosis’ for psychiatry using momentary assessment technology. World Psychiatry 2013; 12: 113–17.
© 2015 Asian Pacific Society of Respirology
SCIENTIFIC LETTER
Medically unexplained dyspnoea and panic ROSE HAUZER,1 WILLEKE VERHEUL,2 ERIC GRIEZ,1 GEERTJAN WESSELING3 AND MARLIES van DUINEN1 Departments of 1Psychiatry and Neuropsychology and 3Respiratory Medicine, Maastricht University, Maastricht, and 2 Department of Psychiatry, Medisch Spectrum Twente, Enschede, The Netherlands
Medically unexplained dyspnoea in the pulmonary setting is often accompanied by considerable levels of anxiety, suggestive of psychopathology, in particular panic disorder (PD). This pilot study investigates the value of the Multidimensional Dyspnea Profile as a tool to facilitate identification of a specific dyspnoea profile suggestive of comorbid PD. The verbal descriptors, feeling depressed, air hunger and concentrating on breathing, significantly differentiated between the two groups of patients with pulmonary disease with and without PD. Key words: chronic lung disease, depressed affect, medically unexplained dyspnoea, Multidimensional Dyspnea Profile, panic disorder. Abbreviations: BMI, body mass index; COPD, chronic obstructive pulmonary disease; MDP, Multidimensional Dyspnea Profile; MUD, medically unexplained dyspnoea; PD, panic disorder; PulnonPD, chronic obstructive pulmonary disease/asthma without panic disorder; PulPD, chronic obstructive pulmonary disease/asthma with panic disorder.
Medically unexplained dyspnoea (MUD) in patients with pulmonary disease leads to considerable use of medical resources and diminished quality of life. MUD patients often present with increased levels of anxiety. MUD and anxiety disorders, in particular panic disorder (PD) have frequently been reported to coexist.1,2 MUD and PD disorders show respiratory symptomatology, with dyspnoea as a core symptom. Dyspnoea is described as the subjective experience of breathing discomfort that subsumes qualitatively distinct sensations with variable intensity.3 The experience of dyspnoea is based on complex interactions of multiple physiological, psychological, social and environmental factors.4 Subtyping of dyspnoea profiles in MUD patients can provide more detailed information on the nature of the complaints, which could facilitate tailored treatment strategies. Correspondence: Marlies van Duinen, Department of Psychiatry and Neuropsychology, Maastricht University, Universiteitssingel 50, PO Box 88, 6200 AB, Maastricht, The Netherlands. Email: [email protected] Received 4 September 2014; invited to revise 10 October 2014; revised 5 January 2015; accepted 21 January 2015 (Associate Editor: Melissa Benton) Article first published online: 30 March 2015 © 2015 Asian Pacific Society of Respirology
The aim of this pilot study is to find dyspnoea modalities using the Multidimensional Dyspnea Profile (MDP) to describe dyspnoea profiles in patients with pulmonary disease with and without PD.5 Fifty-eight patients (36 females/22 males) with confirmed pulmonary disease with dyspnoea, which severity could not be explained by pulmonary physiological parameters, were recruited from the pulmonary outpatient clinic of the university hospital of Maastricht. Mean age was 63.8 ± 9.1 years, mean body mass index (BMI) 27.6 ± 4.7 and mean Tiffeneau index 57.3 ± 18.3 (chronic obstructive pulmonary disease (COPD) only). Forty-three (24 females/19 males) PD patients without documented respiratory disorder were recruited as controls from an academic psychiatric outpatient clinic in Maastricht (mean age: 38.4 ± 12.2 years). The local medical ethics committee approved the study, and written informed consent was obtained from all participants. Intensity of dyspnoea modalities during an episode of breathlessness was assessed retrospectively with the MDP during stable respiratory phase. The MDP is a validated tool used in the pulmonary setting that delineates both sensory and affective dimensions.5,6 The MDP incorporates 0–10 point rating scales (10 = most severe I can imagine) including five sensory descriptors and seven affective descriptors of dyspnoea. An overall descriptor describing the level of unpleasantness was also evaluated on a 0–10 point scale. A psychiatric diagnosis was made according to the Dutch version of the Mini-International Neuropsychiatric Interview according to Diagnostic and Statistical Manual of Mental Disorders-IV7 complemented with expert clinical opinion en peer consensus. Statistical analyses were performed using nonparametric tests (SPSS 17.0 for Windows, SPSS Inc., Chicago, IL, USA). Between-group comparisons for the three diagnostic groups were performed using the Kruskal–Wallis test for individual MDP items. Posthoc testing using the Mann–Whitney U-test compared patients with pulmonary disease and PD (COPD/asthma with panic disorder (PulPD) group) with patients with pulmonary disease without Respirology (2015) 20, 828–830 doi: 10.1111/resp.12516
Medically unexplained dyspnoea and panic
comorbid PD (COPD/asthma without panic disorder (PulnonPD) group). The group of patients with pulmonary disease and MUD consisted of COPD patients (n = 45) and asthma patients (n = 13). Twenty-three patients were diagnosed with PD: 17 COPD and 6 asthma patients. In total, 35 of the 58 interviewed pulmonary patients had a coexisting psychiatric diagnosis including major depression, dysthymic disorder, PD, agoraphobia, specific phobia, obsessive compulsive disorder and generalized anxiety disorder. Twenty-one of these patients had more than one psychiatric diagnosis. There were no significant differences between the PulPD and the PulnonPD group in age, gender, BMI and the presence of comorbid depression. The PD control group was significantly younger compared with the groups with pulmonary pathology. The Mann–Whitney U-test showed statistically significant differences between the PulPD group and the PulnonPD group on some MDP items. The PulPD group showed higher scores on the affective dimension ‘depressed’ (P = 0.041), and on the sensory dimensions ‘air hunger’ (P = 0.013) and ‘concentration’ (P = 0.032). Trends were discovered for the affective measures ‘afraid’ (P = 0.065) and ‘constriction’ (P = 0.073). Figure 1 shows MDP values for the different groups. The aim of this pilot study was to describe different profiles of the MDP in identifying PD in MUD patients with lung pathology. The study demonstrates that in 40% of the cases, MUD could be accounted for by comorbid PD. Assessment of the qualities and intensities of ‘unpleasantness’ and the sensory and affective dimensions of dyspnoea in MUD demonstrated significantly higher scores in PulPD patients within the sensory dimension, on the items ‘air hunger’ and ‘concentrating on breathing’. With regard to the affective dimension, the PD and PulPD reported increased depressive feelings, which was the most pronounced difference between the PulPD and PulnonPD group. This difference was not accounted for by the diagnosis of depression. The experience of pure non-organic dyspnoea, that is panic attack, shows a similar intensity on the sensory quality of ‘air hunger’ as pure organic dyspnoea, underlining the difficulty to identify the cause of dyspnoea in a clinical setting. Even though the absolute difference in score of one point was statistically significant, this is of limited clinical relevance. In addition to biological hypersensitivity to fluctuations in CO2 levels, cognitive models explain a sensitized perception of air hunger by creating a positive feedback loop in PD.8–10 In patients with respiratory impairment and PD, physical exertion can precipitate the perception of threat and anxiety. This triggers physiological arousal, leading to escalating cognitions and recurrent, reinforced depressive feelings. This confirms the earlier finding that depressive symptoms have a strong predictive value.10–12 Concentrating on breathing is a strategy to regain control over the otherwise unconscious process of breathing. In this study, significantly higher scores © 2015 Asian Pacific Society of Respirology
829
Figure 1 Multidimensional Dyspnea Profile (MDP). Median values of the three diagnostic groups are presented for all items. ( ) PulnonPD (chronic obstructive pulmonary disease (COPD)/ asthma without panic disorder; n = 35); ( ) PulPD (COPD/asthma with panic disorder; n = 23); ( ) PD (panic disorder without respiratory disorder; n = 43). *Significance was set at P < 0.05.
were found in PulPD patients and the control PD group for concentrating on breathing, implying an overrepresentation of cognitive compensatory control.13 Scores of PulPD and PulnonPD patients on ‘anxious’, ‘afraid’ and ‘frustration’ during episodes of dyspnoea differed but were statistically comparable. Escalating anxiety in PD is thought to be inhibited in chronic pulmonary patients due to the knowledge of respiratory instability related to structural lung pathology and ascribing failure of compensatory control to inadequate medication prescription. Moreover, adaptation to anxiety and higher CO2 levels might develop in chronic pulmonary patients. In particular, the emotional response of ‘feeling depressed’ and/or ‘concentrating strongly on their breathing’ during dyspnoeic episodes seems to be suggestive of the presence of PD. In order to identify profiles of MDP variables for patients with respiratory disease with or without PD, replication in larger samples is needed. Disruption of respiratory rhythm beyond normal bounds as is seen in dyspnoea is associated with pulmonary disease as well as with PD. This indicates the presence Respirology (2015) 20, 828–830
830 of distinctive dynamics within the respiratory system, leading to separate disease states.14 Describing the intensity of three main variables of the separate disease states (‘air hunger’, ‘depressed affect’ and ‘concentrating on breathing’) and collected serially in real time using a mathematical stochastic model might help to identify chronic pulmonary patients prone to developing comorbid PD at an earlier stage.15 Psychosomatic intervention could be initiated in an early phase with cognitive and/or pharmacologic modification to potentially prevent further disruption of respiratory control and deterioration of illness.
REFERENCES 1 Zandbergen J, Bright M, Pols H, Fernandez I, De Loof C, Griez EJ. Higher lifetime prevalence of respiratory diseases in panic disorder? Am. J. Psychiatry 1991; 148: 1583–5. 2 Han JN, Zhu YJ, Li SW, Luo DM, Hu Z, Van Diest I, De Peuter S, Van de Woestijne KP, Van den Bergh O. Medically unexplained dyspnea: psychophysiological characteristics and role of breathing therapy. Chin. Med. J. 2004; 117: 6–13. 3 Lansing RW, Gracely RH, Banzett RB. The multiple dimensions of dyspnea: review and hypotheses. Respir. Physiol. Neurobiol. 2009; 167: 53–60. 4 Parshall MB, Schwartzstein RM, Adams L, Banzett RB, Manning HL, Bourbeau J, Calverley PM, Gift AG, Harver A, Lareau SC et al. An official American Thoracic Society statement: update on the mechanisms, assessment, and management of dyspnea. Am. J. Respir. Crit. Care Med. 2012; 185: 435–52. 5 Meek PM, Banzett R, Parshall MB, Gracely RH, Schwartzstein RM, Lansing R. Reliability and validity of the multidimensional dyspnea profile. Chest 2012; 141: 1546–53.
Respirology (2015) 20, 828–830
R Hauzer et al. 6 Banzett RB, Pedersen SH, Schwartzstein RM, Lansing RW. The affective dimension of laboratory dyspnea: air hunger is more unpleasant than work/effort. Am. J. Respir. Crit. Care Med. 2008; 177: 1384–90. 7 Sheehan DV, Lecrubier Y, Sheehan KH, Amorim P, Janavs J, Weiller E, Hergueta T, Baker R, Dunbar GC. The MiniInternational Neuropsychiatric Interview (M.I.N.I.): the development and validation of a structured diagnostic psychiatric interview for DSM-IV and ICD-10. J. Clin. Psychiatry 1998; 59(Suppl. 20): 22–33. 8 Colasanti A, Salamon E, Schruers K, Van Diest R, Van Duinen M, Griez E. Carbon dioxide-induced emotion and respiratory symptoms in healthy volunteers. Neuropsychopharmacology 2008; 33: 3103–10. 9 Van Beek N, Griez E. Reactivity to a 35% CO2 challenge in healthy first-degree relatives of patients with panic disorder. Biol. Psychiatry 2000; 47: 830–5. 10 Livermore N, Sharpe L, McKenzie D. Catastrophic interpretations and anxiety sensitivity as predictors of panic-spectrum psychopathology in chronic obstructive pulmonary disease. J. Pychosomatic Research 2012; 72: 388–92. 11 Van Praag HM. Can stress cause depression? Prog. Neuropsychopharmacol Biol. Psychiatry 2004; 28: 891–907. 12 Williams M, Cafarella P, Olds T, Frith PJ. Affective descriptors of the sensation of breathlessness are more highly associated with severity of impairment than physical descriptors in people with COPD. Chest 2010; 138: 315–22. 13 Seth AK. Interoceptive inference, emotion, and the embodied self. Trends Cogn. Sci. 2013; 17: 565–73. 14 Glass L. Synchronization and rhythmic processes in physiology. Nature 2001; 410: 277–84. 15 Van Os J, Delespaul P, Wigman J, Myin-Germeys I, Wichers M. Beyond DSM and ICD: introducing ‘precision diagnosis’ for psychiatry using momentary assessment technology. World Psychiatry 2013; 12: 113–17.
© 2015 Asian Pacific Society of Respirology
