CanJPsychiatry 2013;58(11):646–649
Brief Communication
Craving in Patients With Schizophrenia and Cannabis Use Disorders Thomas Schnell, PhD1; Theresa Becker2; Maria Chantal Thiel3; Euphrosyne Gouzoulis-Mayfrank, MD4 1
Psychologist, Department of Psychiatry and Psychotherapy II, LVR Clinics Cologne, Cologne, Germany; Professor, Department of Clinical Psychology and Psychotherapy, Medical School Hamburg, Hamburg, Germany. Correspondence: Medical School Hamburg (MSH), Am Kaiserkai 1, 20457 Hamburg, Germany; [email protected].
2
Student, Catholic University of Applied Sciences, Cologne, Germany.
3
Student, Department of Clinical Psychology and Psychotherapy, Medical School Hamburg, Hamburg, Germany.
4
Clinical Director, Department of Psychiatry and Psychotherapy II, LVR Clinics Cologne, Cologne, Germany.
Key Words: cannabis, craving, schizophrenia Received, revised, and accepted May 2013.
Objective: Cannabis use is widespread among patients with schizophrenia despite its negative impact on the course of the disease. Craving is a considerable predictor for relapse in people with substance use disorders. Our investigation aimed to gain insight into the intensity and dimensions of cravings in patients with schizophrenia and cannabis use disorders (CUDs), compared with otherwise healthy people with CUDs (control subjects). Method: We examined 51 patients with schizophrenia and CUDs and 51 control subjects by means of the Cannabis-Craving Screening questionnaire. Results: We found greater overall intensity of craving and greater relief craving in patients with schizophrenia and CUDs. Reward craving was greater in the CUDs group. Relief craving was associated with symptoms of schizophrenia in patients with schizophrenia and CUDs. Conclusion: Our findings are in line with the view that aspects of self-medication or affect regulation may account (at least in part) for cannabis use in people with schizophrenia. A better understanding of the dimensions of craving may help to improve targeted therapeutic interventions that aim to reduce drug consumption in this difficult-to-treat patient group. WWW
Désir intense chez les patients souffrant de schizophrénie et de troubles liés à l’utilisation du cannabis Objectif : L’utilisation du cannabis est répandue chez les patients souffrant de schizophrénie, malgré son effet négatif sur l’évolution de la maladie. Le désir intense est un prédicteur considérable de rechute chez les personnes souffrant de troubles liés à l’utilisation d’une substance. Notre recherche visait à obtenir un aperçu de l’intensité et des dimensions des désirs intenses chez les patients souffrant de schizophrénie et de troubles liés à l’utilisation de cannabis (TUC), comparativement à des personnes en santé avec TUC (sujets témoins). Méthode : Nous avons examiné 51 patients souffrant de schizophrénie et de TUC, et 51 sujets témoins au moyen du questionnaire de dépistage du désir intense de cannabis. Résultats : Nous avons observé une intensité générale plus grande du désir intense et un soulagement plus grand du désir intense chez les patients souffrant de schizophrénie et de TUC. Le besoin de récompense était plus grand dans le groupe TUC. Le besoin de soulagement était associé aux symptômes de schizophrénie chez les patients souffrant de schizophrénie et de TUC. Conclusion : Nos résultats rejoignent le point de vue selon lequel des aspects de l’automédication ou de la régulation de l’affect peuvent justifier (du moins en partie) l’utilisation de cannabis chez les personnes souffrant de schizophrénie. Une meilleure compréhension des dimensions du désir intense peut contribuer à améliorer les interventions thérapeutiques ciblées qui visent à réduire la consommation de drogues dans ce groupe de patients difficiles à traiter.
646 W La Revue canadienne de psychiatrie, vol 58, no 11, novembre 2013
www.LaRCP.ca
Craving in Patients With Schizophrenia and Cannabis Use Disorders
C
annabis use is highly prevalent among patients with schizophrenia, particularly with young people, and it is associated with an unfavourable course of the disorder and poor long-term outcomes.1–6 Khantzian7 hypothesized that psychiatric patients use certain drugs against specific symptoms (self-medication hypothesis), while Blanchard et al8 proposed that patients use drugs randomly to turn down unspecific dysphoric states (affect regulation hypothesis). However, empirical findings regarding both hypotheses are heterogenous. In fact, Chambers et al9 suggested that people with schizophrenia use drugs for similar reasons as otherwise healthy users, such as hedonistic pursuit and availability. According to clinical experience, the reasons why patients with schizophrenia use cannabis may be complex and include both hedonistic aspects and relief from distress and dysphoria. Our investigation has its focus on craving for cannabis, which reflects an inner state of mediating between speci fic affective triggers of drug use and the actual act of use. Craving is defined as the intense urge to consume a preferred substance and it is a reason for continued use and for relapses after a period of abstinence.10 Understanding and reducing craving is considered an important key to treating addiction. In recent years, it was proposed that craving consists of 2 distinct dimensions, that involve different psychological and neurobiological mechanisms: reward craving pushes users to consume in anticipation of hedonistic effects, while relief craving urges addicts to consume in anticipation of decreasing a negative affective state. Reward craving involves primarily dopaminergic and opioidergic mechanisms, while relief craving is associated with glutamatergic neurotransmission.11,12
Clinical Implications •
A better understanding of craving in patients with schizophrenia and CUDs may enable therapists to develop a more specific and improved treatment.
•
The great impact of relief craving may influence the kind of neuroleptic medication, as relief craving involves glutamatergic neurotransmission.
•
Atypical antipsychotics with glutamatergic mechanisms could be a favourable pharmacologic strategy in the treatment of patients with schizophrenia and CUDs.
Limitations •
We did not screen the CUDs group for the presence of psychotic symptoms. Therefore, we cannot rule out the possibility of subtle psychotic symptoms in heavy users. Such subthreshold psychotic symptoms may have affected the dimensions of craving.
•
We did not assess the presence of any other psychopathology with standardized instruments. We asked people for past or present psychiatric or psychotherapeutic treatment as a marker of mental health.
•
Patients with schizophrenia and CUDs were in medical treatment, which may have caused them to adjust their ratings in anticipation of acceptability to therapists.
Subjects
Our investigation analyzes the intensity and dimensions of craving for cannabis in people with schizophrenia and CUDs, compared with otherwise healthy people with CUDs. We hypothesized that the 2 groups present no differences in reward craving as the rewarding aspects of cannabis use can apply to both groups. We presumed a higher relief craving in the schizophrenia and CUDs group.
The clinical sample consisted of 51 in- and outpatients of the Psychiatric University Hospital and the Landschaftsverband Rheinland Clinics of Cologne. They were included if they met the DSM-IV-TR criteria for schizophrenia and cannabis abuse or dependence14 (the schizophrenia and CUDs group). The control group consisted of 51 participants who fulfilled the criteria of cannabis abuse or dependence according to DSM-IV-TR and were otherwise healthy (CUDs group). They were recruited at public parks and parties in the drug scene of the city of Cologne. Control subjects were excluded if they had ever been under psychiatric or psychotherapeutic treatment. Exclusion criteria for both groups were as follows: further relevant neuropsychiatric disorders, especially additional substance abuse disorders; no compliance with the requirements of the study; and the inability (or questionable ability) to give informed consent.
Methods
Procedures and Measures
Our study was carried out in compliance with the latest revision of the Declaration of Helsinki13 and was approved by the local ethics committee. Following a detailed study description, written informed consent was obtained from all participants. Abbreviations CCS-7
Cannabis-Craving Screening
CUD
cannabis use disorder
DSM
Diagnostic and Statistical Manual of Mental Disorders
PANSS Positive and Negative Syndrome Scale
www.TheCJP.ca
All diagnoses were verified using the Structured Clinical Interview for DSM-IV-TR.14 In addition, patients with schizophrenia and CUDs underwent a detailed interview on demographics, age at onset of schizophrenia, medication, and patterns of cannabis use (age at onset, average number of joints per month, and time since last dose). Patient data were verified in personal interviews with the attending psychiatrist, as well as by analyzing patient records in case of any further questions. Psychiatric symptoms were assessed using the PANSS.15 Cannabis craving was assessed by means of the CCS-7 questionnaire.16 The CCS-7 consists of 7 items: 3 items for the reward dimension, and 4 items for the relief dimension of craving. Participants had to rate The Canadian Journal of Psychiatry, Vol 58, No 11, November 2013 W 647
Brief Communication
each item on a 7-point Likert scale. In addition, they rated the overall intensity of craving on a 7-point Likert scale.
and there was an association between reward craving and frequency of cannabis use (r = 0.344; P = 0.02).
The same procedure, except regarding clinical features, was applied to the CUDs group.
Discussion
Statistical Analyses
Group differences concerning demographic data and patterns of cannabis use were analyzed using chi-square tests for categorical variables and independent Student t tests for continuous variables. Group differences in craving were analyzed by means of an ANOVA with the 2 factors group (schizophrenia and CUDs, compared with CUDs) and CCS-7 dimension. Further, dimensions of craving were correlated with patterns of cannabis use and psychopathology by means of 2-tailed Pearson correlations. The level of significance was adjusted to 5% and Bonferroni correction was applied. All procedures were performed using SPSS version 15 (SPSS Inc, Chicago, IL).
Results Differences Between Groups and Clinical Characteristics
The schizophrenia and CUDs group tended to be slightly younger than the CUDs group (statistical trend). They had achieved a lower education, compared with the CUDs group, although they had been slightly older when they began using cannabis. They tended to use cannabis more frequently than the CUDs group, although this difference just missed significance, and they reported higher overall intensity of craving, higher relief craving, and lower reward craving, compared with the CUDs group (Table 1). In the schizophrenia and CUDs group, the mean time elapsed since diagnosis of schizophrenia was, on average, 68.5 months (SD 60.76). The mean PANSS positive score was 15.2 (SD 5.59) and the PANSS negative score was 15.5 (SD 5.41). Patients reported, on average, 4.31 psychotic episodes (SD 3.39) since being diagnosed with schizophrenia and they further reported, on average, 4.125 inpatient treatments (SD 3.28). In the schizophrenia and CUDs group, relief craving was associated with the overall intensity of craving (r = 0.695; P = 0.001), as well as with psychopathology according to PANSS—positive symptoms (r = 0.659; P = 0.001) and PANSS—negative symptoms (r = 0.682; P = 0.001). It was negatively correlated with the time elapsed from the last dose of cannabis (r = –0.331; P = 0.04) and positively correlated with the frequency of use (r = 0.452; P = 0.01). Further, the overall (global) intensity of craving was correlated with PANSS—positive symptoms (r = 0.719; P < 0.001) and PANSS—negative symptoms (r = 0.656; P = 0.001). In the CUDs group, the overall intensity of craving and the 2 dimensions, reward and relief craving, were all positively correlated with each other (all about r ≥ 0.5; P < 0.001), 648 W La Revue canadienne de psychiatrie, vol 58, no 11, novembre 2013
In our investigation we aimed to analyze intensity and dimensions of craving for cannabis in patients with schizophrenia and CUDs. For this purpose, we examined 51 patients with schizophrenia and CUDs and 51 otherwise healthy people with CUDs by means of a standardized questionnaire (CCS-7).16 Consistent with previous findings, the schizophrenia and CUDs group achieved a lower level of education, compared with the CUDs group, presumably because the time of onset of schizophrenia interfered with schooling. The schizophrenia and CUDs group tended to use cannabis more frequently than the CUDs group, and they rated the overall intensity of craving and relief craving higher than the CUDs group. In contrast, the CUDs group rated reward craving higher than the schizophrenia and CUDs group. Of special interest were the associations between craving, psychopathology, and parameters of consumption behaviour. Behavioural parameters were associated with the craving dimension that was scored highest in each group; in the CUDs group, the frequency of cannabis use was correlated with reward craving. In contrast, in the schizophrenia and CUDs group the frequency of cannabis use was associated with relief craving and the abstinence time was negatively associated with relief craving. The latter may reflect a decrease of withdrawal symptoms in the course of time from the last dose. Finally, positive and negative symptoms of psychosis were also related to relief craving and the overall intensity of craving. These results are in line with the clinical experience which suggests that the reasons why patients with schizophrenia use cannabis may be complex. Although hedonistic aspects may play a role, aspects of relief from distress and dysphoria seem to have a higher impact. Moreover, the association of relief craving and the overall intensity of craving with psychotic symptoms are in line with the view, that aspects of self-medication or affect regulation may account (at least in part) for drug use in patients with schizophrenia.
Conclusion
As craving plays a critical role in the management of drug use behaviours, and cannabis use has a negative impact on the course of schizophrenia, our findings underline the importance of addressing the issues of craving and motivations to use cannabis in therapeutic interventions. We suggest that therapists should include the issues of dimensions of craving in psychoeducation programs for dually diagnosed patients. In addition, motivational interventions and training of anti-craving skills should be of importance.17 Further, the relation between psychopathology and craving emphasizes the need for a sufficient antipsychotic that may reduce relief craving. www.LaRCP.ca
Craving in Patients With Schizophrenia and Cannabis Use Disorders
Table 1 Presentation of psychopathology (schizophrenia and CUD) and group differences (schizophrenia and CUD, compared with CUD) n = 51 Variable
Schizophrenia and CUD
CUD
Statistical test
P
χ2 = 2.705a
0.10
Demographics Sex Male
30
32
Female
21
19
26.39 (6.5)
29.31 (7.1)
Age, years, mean (SD) Level of education
t = 1.696b
0.06
χ = 27.620a
Brief Communication
Craving in Patients With Schizophrenia and Cannabis Use Disorders Thomas Schnell, PhD1; Theresa Becker2; Maria Chantal Thiel3; Euphrosyne Gouzoulis-Mayfrank, MD4 1
Psychologist, Department of Psychiatry and Psychotherapy II, LVR Clinics Cologne, Cologne, Germany; Professor, Department of Clinical Psychology and Psychotherapy, Medical School Hamburg, Hamburg, Germany. Correspondence: Medical School Hamburg (MSH), Am Kaiserkai 1, 20457 Hamburg, Germany; [email protected].
2
Student, Catholic University of Applied Sciences, Cologne, Germany.
3
Student, Department of Clinical Psychology and Psychotherapy, Medical School Hamburg, Hamburg, Germany.
4
Clinical Director, Department of Psychiatry and Psychotherapy II, LVR Clinics Cologne, Cologne, Germany.
Key Words: cannabis, craving, schizophrenia Received, revised, and accepted May 2013.
Objective: Cannabis use is widespread among patients with schizophrenia despite its negative impact on the course of the disease. Craving is a considerable predictor for relapse in people with substance use disorders. Our investigation aimed to gain insight into the intensity and dimensions of cravings in patients with schizophrenia and cannabis use disorders (CUDs), compared with otherwise healthy people with CUDs (control subjects). Method: We examined 51 patients with schizophrenia and CUDs and 51 control subjects by means of the Cannabis-Craving Screening questionnaire. Results: We found greater overall intensity of craving and greater relief craving in patients with schizophrenia and CUDs. Reward craving was greater in the CUDs group. Relief craving was associated with symptoms of schizophrenia in patients with schizophrenia and CUDs. Conclusion: Our findings are in line with the view that aspects of self-medication or affect regulation may account (at least in part) for cannabis use in people with schizophrenia. A better understanding of the dimensions of craving may help to improve targeted therapeutic interventions that aim to reduce drug consumption in this difficult-to-treat patient group. WWW
Désir intense chez les patients souffrant de schizophrénie et de troubles liés à l’utilisation du cannabis Objectif : L’utilisation du cannabis est répandue chez les patients souffrant de schizophrénie, malgré son effet négatif sur l’évolution de la maladie. Le désir intense est un prédicteur considérable de rechute chez les personnes souffrant de troubles liés à l’utilisation d’une substance. Notre recherche visait à obtenir un aperçu de l’intensité et des dimensions des désirs intenses chez les patients souffrant de schizophrénie et de troubles liés à l’utilisation de cannabis (TUC), comparativement à des personnes en santé avec TUC (sujets témoins). Méthode : Nous avons examiné 51 patients souffrant de schizophrénie et de TUC, et 51 sujets témoins au moyen du questionnaire de dépistage du désir intense de cannabis. Résultats : Nous avons observé une intensité générale plus grande du désir intense et un soulagement plus grand du désir intense chez les patients souffrant de schizophrénie et de TUC. Le besoin de récompense était plus grand dans le groupe TUC. Le besoin de soulagement était associé aux symptômes de schizophrénie chez les patients souffrant de schizophrénie et de TUC. Conclusion : Nos résultats rejoignent le point de vue selon lequel des aspects de l’automédication ou de la régulation de l’affect peuvent justifier (du moins en partie) l’utilisation de cannabis chez les personnes souffrant de schizophrénie. Une meilleure compréhension des dimensions du désir intense peut contribuer à améliorer les interventions thérapeutiques ciblées qui visent à réduire la consommation de drogues dans ce groupe de patients difficiles à traiter.
646 W La Revue canadienne de psychiatrie, vol 58, no 11, novembre 2013
www.LaRCP.ca
Craving in Patients With Schizophrenia and Cannabis Use Disorders
C
annabis use is highly prevalent among patients with schizophrenia, particularly with young people, and it is associated with an unfavourable course of the disorder and poor long-term outcomes.1–6 Khantzian7 hypothesized that psychiatric patients use certain drugs against specific symptoms (self-medication hypothesis), while Blanchard et al8 proposed that patients use drugs randomly to turn down unspecific dysphoric states (affect regulation hypothesis). However, empirical findings regarding both hypotheses are heterogenous. In fact, Chambers et al9 suggested that people with schizophrenia use drugs for similar reasons as otherwise healthy users, such as hedonistic pursuit and availability. According to clinical experience, the reasons why patients with schizophrenia use cannabis may be complex and include both hedonistic aspects and relief from distress and dysphoria. Our investigation has its focus on craving for cannabis, which reflects an inner state of mediating between speci fic affective triggers of drug use and the actual act of use. Craving is defined as the intense urge to consume a preferred substance and it is a reason for continued use and for relapses after a period of abstinence.10 Understanding and reducing craving is considered an important key to treating addiction. In recent years, it was proposed that craving consists of 2 distinct dimensions, that involve different psychological and neurobiological mechanisms: reward craving pushes users to consume in anticipation of hedonistic effects, while relief craving urges addicts to consume in anticipation of decreasing a negative affective state. Reward craving involves primarily dopaminergic and opioidergic mechanisms, while relief craving is associated with glutamatergic neurotransmission.11,12
Clinical Implications •
A better understanding of craving in patients with schizophrenia and CUDs may enable therapists to develop a more specific and improved treatment.
•
The great impact of relief craving may influence the kind of neuroleptic medication, as relief craving involves glutamatergic neurotransmission.
•
Atypical antipsychotics with glutamatergic mechanisms could be a favourable pharmacologic strategy in the treatment of patients with schizophrenia and CUDs.
Limitations •
We did not screen the CUDs group for the presence of psychotic symptoms. Therefore, we cannot rule out the possibility of subtle psychotic symptoms in heavy users. Such subthreshold psychotic symptoms may have affected the dimensions of craving.
•
We did not assess the presence of any other psychopathology with standardized instruments. We asked people for past or present psychiatric or psychotherapeutic treatment as a marker of mental health.
•
Patients with schizophrenia and CUDs were in medical treatment, which may have caused them to adjust their ratings in anticipation of acceptability to therapists.
Subjects
Our investigation analyzes the intensity and dimensions of craving for cannabis in people with schizophrenia and CUDs, compared with otherwise healthy people with CUDs. We hypothesized that the 2 groups present no differences in reward craving as the rewarding aspects of cannabis use can apply to both groups. We presumed a higher relief craving in the schizophrenia and CUDs group.
The clinical sample consisted of 51 in- and outpatients of the Psychiatric University Hospital and the Landschaftsverband Rheinland Clinics of Cologne. They were included if they met the DSM-IV-TR criteria for schizophrenia and cannabis abuse or dependence14 (the schizophrenia and CUDs group). The control group consisted of 51 participants who fulfilled the criteria of cannabis abuse or dependence according to DSM-IV-TR and were otherwise healthy (CUDs group). They were recruited at public parks and parties in the drug scene of the city of Cologne. Control subjects were excluded if they had ever been under psychiatric or psychotherapeutic treatment. Exclusion criteria for both groups were as follows: further relevant neuropsychiatric disorders, especially additional substance abuse disorders; no compliance with the requirements of the study; and the inability (or questionable ability) to give informed consent.
Methods
Procedures and Measures
Our study was carried out in compliance with the latest revision of the Declaration of Helsinki13 and was approved by the local ethics committee. Following a detailed study description, written informed consent was obtained from all participants. Abbreviations CCS-7
Cannabis-Craving Screening
CUD
cannabis use disorder
DSM
Diagnostic and Statistical Manual of Mental Disorders
PANSS Positive and Negative Syndrome Scale
www.TheCJP.ca
All diagnoses were verified using the Structured Clinical Interview for DSM-IV-TR.14 In addition, patients with schizophrenia and CUDs underwent a detailed interview on demographics, age at onset of schizophrenia, medication, and patterns of cannabis use (age at onset, average number of joints per month, and time since last dose). Patient data were verified in personal interviews with the attending psychiatrist, as well as by analyzing patient records in case of any further questions. Psychiatric symptoms were assessed using the PANSS.15 Cannabis craving was assessed by means of the CCS-7 questionnaire.16 The CCS-7 consists of 7 items: 3 items for the reward dimension, and 4 items for the relief dimension of craving. Participants had to rate The Canadian Journal of Psychiatry, Vol 58, No 11, November 2013 W 647
Brief Communication
each item on a 7-point Likert scale. In addition, they rated the overall intensity of craving on a 7-point Likert scale.
and there was an association between reward craving and frequency of cannabis use (r = 0.344; P = 0.02).
The same procedure, except regarding clinical features, was applied to the CUDs group.
Discussion
Statistical Analyses
Group differences concerning demographic data and patterns of cannabis use were analyzed using chi-square tests for categorical variables and independent Student t tests for continuous variables. Group differences in craving were analyzed by means of an ANOVA with the 2 factors group (schizophrenia and CUDs, compared with CUDs) and CCS-7 dimension. Further, dimensions of craving were correlated with patterns of cannabis use and psychopathology by means of 2-tailed Pearson correlations. The level of significance was adjusted to 5% and Bonferroni correction was applied. All procedures were performed using SPSS version 15 (SPSS Inc, Chicago, IL).
Results Differences Between Groups and Clinical Characteristics
The schizophrenia and CUDs group tended to be slightly younger than the CUDs group (statistical trend). They had achieved a lower education, compared with the CUDs group, although they had been slightly older when they began using cannabis. They tended to use cannabis more frequently than the CUDs group, although this difference just missed significance, and they reported higher overall intensity of craving, higher relief craving, and lower reward craving, compared with the CUDs group (Table 1). In the schizophrenia and CUDs group, the mean time elapsed since diagnosis of schizophrenia was, on average, 68.5 months (SD 60.76). The mean PANSS positive score was 15.2 (SD 5.59) and the PANSS negative score was 15.5 (SD 5.41). Patients reported, on average, 4.31 psychotic episodes (SD 3.39) since being diagnosed with schizophrenia and they further reported, on average, 4.125 inpatient treatments (SD 3.28). In the schizophrenia and CUDs group, relief craving was associated with the overall intensity of craving (r = 0.695; P = 0.001), as well as with psychopathology according to PANSS—positive symptoms (r = 0.659; P = 0.001) and PANSS—negative symptoms (r = 0.682; P = 0.001). It was negatively correlated with the time elapsed from the last dose of cannabis (r = –0.331; P = 0.04) and positively correlated with the frequency of use (r = 0.452; P = 0.01). Further, the overall (global) intensity of craving was correlated with PANSS—positive symptoms (r = 0.719; P < 0.001) and PANSS—negative symptoms (r = 0.656; P = 0.001). In the CUDs group, the overall intensity of craving and the 2 dimensions, reward and relief craving, were all positively correlated with each other (all about r ≥ 0.5; P < 0.001), 648 W La Revue canadienne de psychiatrie, vol 58, no 11, novembre 2013
In our investigation we aimed to analyze intensity and dimensions of craving for cannabis in patients with schizophrenia and CUDs. For this purpose, we examined 51 patients with schizophrenia and CUDs and 51 otherwise healthy people with CUDs by means of a standardized questionnaire (CCS-7).16 Consistent with previous findings, the schizophrenia and CUDs group achieved a lower level of education, compared with the CUDs group, presumably because the time of onset of schizophrenia interfered with schooling. The schizophrenia and CUDs group tended to use cannabis more frequently than the CUDs group, and they rated the overall intensity of craving and relief craving higher than the CUDs group. In contrast, the CUDs group rated reward craving higher than the schizophrenia and CUDs group. Of special interest were the associations between craving, psychopathology, and parameters of consumption behaviour. Behavioural parameters were associated with the craving dimension that was scored highest in each group; in the CUDs group, the frequency of cannabis use was correlated with reward craving. In contrast, in the schizophrenia and CUDs group the frequency of cannabis use was associated with relief craving and the abstinence time was negatively associated with relief craving. The latter may reflect a decrease of withdrawal symptoms in the course of time from the last dose. Finally, positive and negative symptoms of psychosis were also related to relief craving and the overall intensity of craving. These results are in line with the clinical experience which suggests that the reasons why patients with schizophrenia use cannabis may be complex. Although hedonistic aspects may play a role, aspects of relief from distress and dysphoria seem to have a higher impact. Moreover, the association of relief craving and the overall intensity of craving with psychotic symptoms are in line with the view, that aspects of self-medication or affect regulation may account (at least in part) for drug use in patients with schizophrenia.
Conclusion
As craving plays a critical role in the management of drug use behaviours, and cannabis use has a negative impact on the course of schizophrenia, our findings underline the importance of addressing the issues of craving and motivations to use cannabis in therapeutic interventions. We suggest that therapists should include the issues of dimensions of craving in psychoeducation programs for dually diagnosed patients. In addition, motivational interventions and training of anti-craving skills should be of importance.17 Further, the relation between psychopathology and craving emphasizes the need for a sufficient antipsychotic that may reduce relief craving. www.LaRCP.ca
Craving in Patients With Schizophrenia and Cannabis Use Disorders
Table 1 Presentation of psychopathology (schizophrenia and CUD) and group differences (schizophrenia and CUD, compared with CUD) n = 51 Variable
Schizophrenia and CUD
CUD
Statistical test
P
χ2 = 2.705a
0.10
Demographics Sex Male
30
32
Female
21
19
26.39 (6.5)
29.31 (7.1)
Age, years, mean (SD) Level of education
t = 1.696b
0.06
χ = 27.620a
