Is cannabis treatment for anxiety,mood, and related disorders ready for prime time?

Anxiety and related disorders are the most common mental conditions affecting the North American population. Despite their established efficacy, first-line antidepressant treatments are associated with significant side effects, leading many afflicted individuals to seek alternative treatments. Cannabis is commonly viewed as a natural alternative for a variety of medical and mental health conditions. Currently, anxiety ranks among the top five medical symptoms for which North Americans report using medical marijuana. However, upon careful review of the extant treatment literature, the anxiolytic effects of cannabis in clinical populations are surprisingly not well-documented. The effects of cannabis on anxiety and mood symptoms have been examined in healthy populations and in several small studies of synthetic cannabinoid agents but there are currently no studies which have examined the effects of the cannabis plant on anxiety and related disorders. In light of the rapidly shifting landscape regarding the legalization of cannabis for medical and recreational purposes, it is important to highlight the significant disconnect between the scientific literature, public opinion, and related policies. The aim of this article is to provide a comprehensive review of the current cannabis treatment literature, and to identify the potential for cannabis to be used as a therapeutic intervention for anxiety, mood, and related disorders. Searches of five electronic databases were conducted (PubMed, MEDLINE, Web of Science, PsychINFO, and Google Scholar), with the most recent in February 2017. The effects of cannabis on healthy populations and clinical psychiatric samples will be discussed, focusing primarily on anxiety and mood disorders.     

Lifetime positive symptoms in patients with schizophrenia and cannabis abuse are partially explained by co-morbid addiction

Recent prospective findings have shown that cannabis use by young people could be a risk factor for psychotic symptoms in adulthood, but the long-term impact of cannabis abuse on the clinical features of declared schizophrenia remains to be explored. We assessed the independent influence of cannabis abuse on the clinical symptoms of schizophrenia, after controlling for frequently co-occurring addictive disorders. Patients with schizophrenia, and with (N=66), or without (N=139) cannabis abuse, were compared for lifetime positive and negative symptoms, taking into account presence of any other addictive disorders. The incidence of the abuse of drugs other than cannabis was nearly five times greater amongst patients with both schizophrenia and cannabis abuse. When the analyses were limited to subjects with no other abuse, less avolution and fewer apathy symptoms were still detected in patients with schizophrenia and cannabis abuse than in those with no abuse (p=0.0001). In contrast, between-group differences for positive symptoms were abolished when multiple substance abuses were taken into account. The strong association between cannabis abuse and fewer negative symptoms in schizophrenia was thus replicated in this sample, but once co-morbid addictive disorders had been controlled no influence of cannabis abuse on hallucinations was detected. Distinguishing the effects of co-occurring addictive disorder(s) in patients with schizophrenia and cannabis dependence may thus be important when attempting to analyse the impact of cannabis abuse.     

How High? Trends in Cannabis Use Prior to First Admission to Inpatient Psychiatry in Ontario,Canada, between 2007 and 2017

Objectives:To examine the trends in cannabis use within 30 days of first admission to inpatient psychiatry in Ontario, Canada, between 2007 and 2017, and the characteristics of persons reporting cannabis use.Methods:A retrospective cross-sectional analysis was conducted for first-time admissions to nonforensic inpatient psychiatric beds in Ontario, Canada, between January 1, 2007, and December 31, 2017, using data from the Ontario Mental Health Reporting System (N = 81,809).Results:Across all years, 20.1% of patients reported cannabis use within 30 days of first admission. Use increased from 16.7% in 2007 to 25.9% in 2017, and the proportion with cannabis use disorders increased from 3.8% to 6.0%. In 2017, 47.9% of patients aged 18 to 24 and 39.2% aged 25 to 34 used cannabis, representing absolute increases of 8.3% and 10.7%, respectively. Increases in cannabis use were found across almost all diagnostic groups, with the largest increases among patients with personality disorders (15% increase), schizophrenia or other psychotic disorders (14% increase), and substance use disorders (14% increase). A number of demographic and clinical factors were significantly associated with cannabis use, including interactions between schizophrenia and gender (area under the curve = 0.88).Conclusions:As medical cannabis policies in Canada have evolved, cannabis use reported prior to first admission to inpatient psychiatry has increased. The findings of this study establish a baseline for evaluating the impact of changes in cannabis-related policies in Ontario on cannabis use prior to admission to inpatient psychiatry.     

Cannabis et trouble bipolaire : recherche d’une association à partir d’une revue de la littérature

Introduction

It has been established that cannabis use is involved in the emergence and evolution of psychotic disorders. Although cannabis use is very frequent in mood disorders, there has been a considerable debate about the association observed between these two disorders. This review aims to clarify the relation between cannabis use and bipolar disorder, in order to unveil a possible causality and find the effect of cannabis on the prognosis and expression of bipolarity.

Methods

The review used MedLine database using the keywords “cannabis” or “marijuana” and “bipolar” or “mania” or “depression”. This search found 36 articles who were clinically relevant to the subject and were included and discussed in this review.

Results

The first studies discussing the link between cannabis use and psychotic disorders reveal manic features in the substance abuse group, hence suggesting a possible association between cannabis use and bipolar disorder, in favor of triggering a manic episode. According to the studies, between 25 and 64% of bipolar patients are cannabis users, and the prevalence is higher in younger and male patients. The risk of developing a mood disorder is higher among cannabis users compared to the general population. This substance abuse in bipolar disorders would increase the frequency and duration of manic episodes without changing the total duration of mood episodes. In a first episode of bipolar disorder, the use of cannabis would increase the rate of relapses of manic episodes and worsen the prognosis of the disorder.

Discussion

The frequency of substance abuse in bipolar disorders is higher than the prevalence in the general population, and cannabis is one of the most used illegal substances in the worldwide. Hence, the association between cannabis use and bipolar disorders is frequent. Cannabis users may experience euphoria, relaxation and subjective feelings of well-being; this substance may also have antiepileptic effect, which may explain some of the effects of cannabis on bipolar disorders. In fact, the use of cannabis would increase the frequency and duration of manic episodes in bipolar patients without increasing the total duration of mood episodes, suggesting a possible antidepressing and mood stabilizing effects. This impact of cannabis on mood disorders and its possible pharmacological effect is still controversial and needs further experiencing to be proved.     

Reasons for cannabis use in psychosis

OBJECTIVE: To examine the reasons for cannabis use among individuals with psychotic disorders. METHOD: Forty-nine people with psychotic disorders in treatment with community health centres in Northern Sydney were interviewed to collect information about their experience of antipsychotic side-effects and their influence on cannabis use. Other information collected on cannabis use included: amount and frequency, effects of use and other general reasons given for use. RESULTS: It was found that boredom, social motives, improving sleep, anxiety and agitation and symptoms associated with negative psychotic symptoms or depression were the most important motivators of cannabis use. Positive symptoms of psychosis and antipsychotic side-effects that were not associated with anxiety, were not important motivators of cannabis use. CONCLUSIONS: As cannabis use may precipitate relapse in this population, it is important to reduce these motivators of use. Clinician's must assess and treat these problems, thus reducing the need for patients to self-medicate with cannabis, and therefore reducing the risk of relapse.     

The effects of cannabis use on neurocognition in schizophrenia: a meta-analysis

Patients with schizophrenia frequently report cannabis use, yet its effects on neurocognitive functioning in this population are still unclear. This meta-analysis was conducted to determine the magnitude of effect of cannabis consumption on cognition in schizophrenia without the confounding effects of other co-morbid substance use disorders. Eight studies met inclusion criteria yielding a total sample of 942. Three hundred and fifty six of these participants were cannabis users with schizophrenia, and 586 were patients with no cannabis use. Neuropsychological tests were grouped into seven domains (general cognitive ability and intelligence; selective, sustained and divided attention; executive abilities; working memory and learning; retrieval and recognition; receptive and expressive language abilities and visuo-spatial and construction abilities). Effect sizes were computed for each cognitive domain between cannabis-using patients and patients with no history of cannabis use. Effect size differences in cognitive performance in the schizophrenia group as a function of cannabis use were in the small to medium range, denoting superior performance in cannabis-using patients. Explanations for these findings are discussed and suggestions for future research in this area are recommended.     

Iowa gambling task in schizophrenia: a review and new data in patients with schizophrenia and co-occurring cannabis use disorders

BACKGROUND: We reviewed previous studies comparing schizophrenia patients and healthy subjects for performance on the Iowa Gambling Task (IGT) (a laboratory task designed to measure emotion-based decision-making), and found mixed results. We hypothesize that deficits in IGT performance in schizophrenia may be more specifically related to concurrent substance use disorders. To test this hypothesis, we compared schizophrenia patients with (SCZ((+))) or without (SCZ((-))) cannabis use disorders, to healthy subjects, on measures of cognition and IGT performance. METHODS: A comprehensive battery of cognitive tests and the IGT were administered to three groups of subjects: (1) 13 subjects with DSM-IV diagnosis of schizophrenia and no concurrent substance use disorders (mean age: 28+/-12 (SD); 54% males); (2) 14 subjects with schizophrenia and concurrent cannabis use disorders (mean age: 29+/-9 (SD); 71% males); and (3) 20 healthy subjects (mean age 33+/-10 (SD); 60% males). RESULTS: Compared to the healthy group, both schizophrenia groups were cognitively more impaired, and did worse on IGT performance. There were no differences between SCZ((+)) and SCZ((-)) patients on most of the cognitive tests, and IGT performance. CONCLUSIONS: Schizophrenia patients show widespread impairments in several cognitive domains and emotion-based decision-making. These results are consistent with the evidence that schizophrenia reflects a dorsolateral and orbitofrontal/ventromedial prefrontal cortex dysfunction. More intriguing, it appears that the concurrent abuse of cannabis has no compounding effects on cognition, as well as emotion/affect-based decision-making.     

State of the art treatments for cannabis dependence

The treatment of cannabis dependence can be viewed as a cup half empty or half full. On the one hand, few people who might benefit from treatment actually receive it. Among those who undergo treatment in randomized trials, long-term abstinence is achieved by fewer than 20%. Moderate use goals have been associated with decreases in consequences, but the differential impact of such goals on the long-term course of cannabis dependence is unknown. Optimal duration of treatment is unclear, and certain populations, particularly patients with co-occurring disorders, have not been studied adequately. Twelve-step programs are low cost, effective for other substance use disorders, and readily available in most regions of the world. However, their role and efficacy in cannabis dependence has not been examined. Finally, effective pharmacologic treatments are under development, but none have yet been firmly established. On the other hand, psychotherapeutic strategies used to treat other substance use disorders can be effective for cannabis dependence. A recent meta-analysis of psychosocial interventions for illicit substance use disorders found that treatments for cannabis dependence had comparatively larger effect sizes than treatments for other substance use disorders. Combination therapies have proven most effective, particularly those that begin with a motivational intervention, utilize incentives to enhance the commitment to change, and teach behavioral and cognitive copings skills to prevent relapse. Among adolescents, family engagement and collaboration with community stakeholders adds substantial value. Although only 9% of cannabis users develop cannabis dependence, the volume of people who smoke cannabis ensures that the total number of people in need of help is larger than the capacity of substance abuse specialty services. Thus, although efforts to refine and improve the efficacy of treatment interventions continue, innovations that increase the availability and accessibility of treatment are also needed. Computer- and phone-based interventions, social media, and brief interventions that can be implemented in primary care settings are areas that may hold promise for reaching at-risk populations. Adolescents and persons with co-occurring mental illness are at particularly high risk of cannabis dependence, and may suffer disproportionately from cannabis’s adverse effects. As in the treatment of other substance use disorders, there is a need for a continuing care model with long-term follow-up that extends past the periods typically evaluated in treatment studies. Additionally, there is a need for further investigation of genetic underpinnings and endophenotypes underlying cannabis dependence to identify neurobiological mechanisms for targeted intervention. One benefit of the societal focus on cannabis has been a prominent increase in research covering everything from the basic science to public health impact of cannabis. Over the next decade, physicians who provide treatment for individuals with cannabis dependence are likely to see their armamentarium of effective interventions expand, to the ultimate betterment of patients, their families, and society at large.     

The current status of artisanal cannabis for the treatment of epilepsy in the United States

The widespread patient use of artisanal cannabis preparations has preceded quality validation of cannabis use for epilepsy. Neurologists and cannabinoid specialists are increasingly in a position to monitor and guide the use of herbal cannabis in epilepsy patients. We report the retrospective data on efficacy and adverse effects of artisanal cannabis in Patients with medically refractory epilepsy with mixed etiologies in Washington State, California, and Maine. Clinical considerations, including potential risks and benefits, challenges related to artisanal preparations, and cannabinoid dosing, are discussed.ResultsOf 272 combined patients from Washington State and California, 37 (14%) found cannabis ineffective at reducing seizures, 29 (15%) experienced a 1–25% reduction in seizures, 60 (18%) experienced a 26–50% reduction in seizures, 45 (17%) experienced a 51–75% reduction in seizures, 75 (28%) experienced a 76–99% reduction in seizures, and 26 (10%) experienced a complete clinical response. Overall, adverse effects were mild and infrequent, and beneficial side effects such as increased alertness were reported. The majority of patients used cannabidiol (CBD)-enriched artisanal formulas, some with the addition of delta-9-tetrahydrocannabinol (THC) and tetrahydrocannabinolic acid (THCA). Four case reports are included that illustrate clinical responses at doses < 0.1 mg/kg/day, biphasic dose–response effects, the use of THCA for seizure prevention, the use of THC for seizure rescue, and the synergy of cannabinoids and terpenoids in artisanal preparations.This article is part of a Special Issue entitled "Cannabinoids and Epilepsy".     

Axis II comorbidity of substance use disorders among patients referred for treatment of personality disorders.

OBJECTIVE: The purpose of this study was to determine the extent of comorbid substance use disorders in patients referred for treatment of personality disorders. METHOD: Two hundred inpatients and outpatients were assessed by semistructured interviews for substance use and personality disorders. Univariate odds ratios were calculated for groups of substance use disorders and each DSM-III-R axis II disorder; comorbidity among axis II disorders was controlled in multivariate models predicting current or lifetime substance use disorder groups. The impact of personality disorder on chronicity and overall impairment associated with substance use disorders was evaluated. RESULTS: Close to 60% of subjects with substance use disorders had personality disorders. Borderline personality disorder was significantly associated with current substance use disorders, excluding alcohol and cannabis, and with lifetime alcohol, stimulant, and other substance use disorders, excluding cannabis. Antisocial personality disorder was associated with lifetime substance use disorders other than alcohol, cannabis, and stimulants. These relationships remained significant after controlling for the presence of all other personality disorders. There was no evidence that personality disorders increased the chronicity of substance use disorders, but comorbid personality disorders were associated with greater global impairment. CONCLUSIONS: Borderline personality disorder may be associated with a wide variety of substance use disorders, especially among patients seeking treatment for personality problems.     

Indications of a dose–response relationship between cannabis use and age at onset in bipolar disorder

Cannabis use seems to play a causal role in the development of psychotic disorders. Recent evidence suggests that it may also precipitate onset in bipolar disorder. We here investigate if there is a dose–response relationship between cannabis use and age at onset in bipolar disorder, and whether there are interactions between cannabis use and illness characteristics (presenting polarity and presence of psychosis). Consecutively recruited patients with a DSM-IV, SCID verified diagnosis of bipolar I, II or NOS disorder (n=324) participated. Two-way ANCOVAS were used to investigate the effect of levels of cannabis use (<10 times during one month lifetime, >10 times during one month lifetime or a cannabis use disorder) on age at onset, including interaction effects with illness characteristics, while controlling for possible confounders. There was a significant association indicating a dose–response relationship between cannabis use and age at onset, which remained statistically significant after controlling for possible confounders (gender, bipolar subtype, family history of severe mental illness and alcohol or other substance use disorders). There were no interaction effects between cannabis use and presenting polarity or presence of psychosis. Doses of cannabis used may affect the age at onset of bipolar disorder.     

Effects of co-occurring cannabis use disorders on the course of bipolar disorder after a first hospitalization for mania

CONTEXT: Cannabis use disorders commonly co-occur in bipolar disorder; however, the effects of cannabis abuse on outcome have been minimally studied. OBJECTIVE: To identify how the sequence of the onsets of a cannabis use disorder and bipolar disorder is associated with the subsequent course of each condition. DESIGN: Inception cohort. SETTING: Academic medical center. PATIENTS: Patients (N = 144) were studied who met criteria for bipolar I disorder (manic or mixed), were 12 to 45 years old, and had no previous hospitalizations and minimal previous treatment. Patients were followed up for up to 5 years and included 33 in whom the onset of a cannabis use disorder preceded the onset of bipolar disorder (cannabis first), 36 in whom bipolar disorder onset preceded the onset of cannabis abuse (bipolar first), and 75 with bipolar disorder only. MAIN OUTCOME MEASURES: Symptomatic recovery and recurrence of both conditions and percentage of follow-up time with affective and cannabis use disorder symptoms. RESULTS: The cannabis first group exhibited better recovery than the other groups, although when adjusted for potential mediator variables these results did not persist. Cannabis use was associated with more time in affective episodes and with rapid cycling. Most cannabis use disorders remitted immediately after hospitalization, followed by rapid rates of recurrence. CONCLUSIONS: The effects of the sequence of onsets of bipolar and cannabis use disorders were less pronounced than observed in co-occurring alcohol and bipolar disorders. Aggressive drug abuse treatment immediately after a first psychiatric hospitalization might decrease rates of recurrence and new cases of cannabis use disorder in the course of bipolar disorder.     

Alcohol and cannabis use in schizophrenia: effects of clozapine vs. risperidone

BACKGROUND: Alcohol and cannabis use disorders worsen the course of schizophrenia. While the typical antipsychotics are of limited value in controlling substance use in schizophrenic patients, previous studies suggest that the novel antipsychotic clozapine (CLOZ) may decrease their substance use. We describe a retrospective study of the effects of the novel antipsychotics risperidone (RISP) and clozapine on alcohol and cannabis use in patients with schizophrenia or schizoaffective disorder and comorbid alcohol and/or cannabis use disorder. METHOD: This study involved retrospective assessment of abstinence (cessation of alcohol and cannabis use) in 41 patients treated with either risperidone (n=8) or clozapine (n=33) for at least 1 year. In 32 of these 41 patients, information was available on whether abstinence occurred during the 1-year period. RESULTS: Abstinence rates were significantly higher in patients treated with clozapine than in those treated with risperidone (54% vs. 13%, p=0.05). The nine patients treated for at least 1 year, but excluded from the analysis because time of cessation of use was not known, had all stopped alcohol/cannabis use during clozapine treatment. DISCUSSION: While the limitations of this retrospective study must be recognized, the data suggest that comorbid patients treated with clozapine are more likely to abstain from alcohol and cannabis use than are those treated with risperidone. Further prospective studies will be required to confirm these intriguing results.     

Inanspruchnahmepopulation einer Cannabisambulanz

BACKGROUND: There has been an increase of cannabis-related disorders in Germany during the last 10 years. According treatments are being established, however little is known about the treatment populations. METHODS: The population of an outpatient treatment program for diagnosis and therapy of cannabis-related disorders was investigated using a structured interview (based on EuropASI, SCID-I) regarding sociodemographic variables, history of addiction, consumption patterns, and psychiatric comorbidity. RESULTS: The 90 patients studied had a mean age of 27.5+/-6.6 years; 82% were male. They claimed averages of cannabis consumption for 11+/-7 years and current amount at 1.9 g per day. Alcohol problems were also common in this sample. High percentages were shown regarding unemployment, living alone, and problems with the law. Comorbid psychiatric disorders were diagnosed in 42% of patients. CONCLUSIONS: The patients were chronic users of cannabis with extensive psychosocial problems. Therapy of cannabis-related disorders should therefore include treatment for comorbidities and social care besides the treatment for addictive behavior.     

First episode schizophrenia-related psychosis and substance use disorders: acute response to olanzapine and haloperidol

BACKGROUND: Co-occurring substance use disorders, mostly involving alcohol, cannabis or cocaine, occur commonly in patients with schizophrenia and are associated with increased morbidity and mortality. Available but limited data suggest that substance use disorders (especially cannabis use disorders) may also be common in first-episode patients and appear linked to a poor outcome in these patients. Strategies to curtail substance use form an important dimension of the treatment program for both first-episode and chronic patients. We report on rates of co-occurring substance use disorders in patients within their first episode of schizophrenia-related psychosis from a multicenter, international treatment trial of olanzapine vs. haloperidol. METHODS: The study involved 262 patients (of 263 who were randomized and who returned for a post-randomization evaluation) within their first episode of psychosis (schizophrenia, schizoaffective disorder or schizophreniform disorder) recruited from 14 academic medical centers in North America and Western Europe. Patients with a history of substance dependence within 1 month prior to entry were excluded. RESULTS: Of this sample, 97 (37%) had a lifetime diagnosis of substance use disorder (SUD); of these 74 (28% of the total) had a lifetime cannabis use disorder (CUD) and 54 (21%) had a lifetime diagnosis of alcohol use disorder (AUD). Patients with SUD were more likely to be men. Those with CUD had a lower age of onset than those without. Patients with SUD had more positive symptoms and fewer negative symptoms than those without SUD, and they had a longer duration of untreated psychosis. The 12-week response data indicated that 27% of patients with SUD were responders compared to 35% of those without SUD. Patients with AUD were less likely to respond to olanzapine than those without AUD. DISCUSSION: These data suggest that first-episode patients are quite likely to have comorbid substance use disorders, and that the presence of these disorders may negatively influence response to antipsychotic medications, both typical and atypical antipsychotics, over the first 12 weeks of treatment.     

Substance use disorder in hospitalized severely mentally ill psychiatric patients: prevalence, correlates, and subgroups

The prevalence and demographic and clinical correlates of lifetime substance use disorders were examined in a cohort of 325 recently hospitalized psychiatric patients (53% schizophrenia or schizoaffective disorder). Alcohol use was the most common type of substance use disorder, followed by cannabis and cocaine use. Univariate analyses indicated that gender (male), age (younger), education (less), history of time in jail, conduct disorder symptoms, and antisocial personality disorder symptoms were predictive of substance use disorders. Lifetime cannabis use disorder was uniquely predicted by marital status (never married) and fewer psychiatric hospitalizations during the previous 6 months. Optimal classification tree analysis, an exploratory, nonlinear method of identifying patient subgroups, was successful in predicting 74 percent to 86 percent of the alcohol, cannabis, and cocaine use disorders. The implications of this method for identifying specific patient subgroups and service needs are discussed.     

Cannabis use and psychiatric and cogitive disorders: the chicken or the egg?

PURPOSE OF REVIEW: Cannabis is the world's most commonly used illicit drug. In this review, we consider the recent literature on the effects of cannabis on mental health and on cognition. RECENT FINDINGS: Cannabis use in adolescence increases the risk of later schizophrenia-like psychoses, especially in genetically vulnerable individuals. Not surprisingly, patients already suffering from psychosis who use cannabis have a worse outcome than those who do not. These effects of cannabis may be consequent on its impact on the dopamine system. There is less evidence of cannabis playing an aetiological role in other mental disorders including depression, but there have been far fewer studies. Heavy cannabis use has also been shown to affect memory and learning performance, both in healthy individuals and in patients suffering from psychosis. Combined cognitive-behavioural therapy and motivational interviewing seems a promising psychological intervention to achieve a cessation of cannabis use in patients suffering from schizophrenia. SUMMARY: Further research is needed to understand the biological mechanisms underlying the effects of cannabis on mental health, but intervention strategies to help patients abstain should currently be implemented in psychiatric services, and public education campaigns should be directed at increasing awareness of the health risks of cannabis.     

Motivations that maintain substance use among individuals with psychotic disorders

This study quantitatively examined reasons for substance use among individuals with psychotic disorders and explored the relationship of these reasons to substance use problems and dependence. Sixty-nine people with psychotic disorders were interviewed using a battery of questionnaires called the Substance Use Scale for Psychosis (SUSP). Symptoms and medication side effects were also measured. A factor analysis revealed similar motives for substance use (mostly alcohol and cannabis use) as in the general population: "enhancement," "social motives," "coping with unpleasant affect," and "conformity and acceptance." A fifth factor, "relief of positive symptoms and side effects," demonstrated limited reliability. "Coping" and "enhancement" motives were found to lead to substance use problems and dependence. Mediator analysis indicated that worse symptoms lead to stronger motives for substance use, which in turn lead to stronger psychological dependence on that substance. These findings have the potential to inform effective treatment for substance use in psychosis.     

Impact of Cannabis Use on Long-Term Remission in Bipolar I and Schizoaffective Disorder

Objective

To investigate the impact of regular cannabis use on long-term remission of mood symptoms in bipolar spectrum disorders.

Methods

The 24-month prospective observational study included patients (n=239) with bipolar I disorder and schizoaffective disorder, bipolar type. Participants were classified as regular cannabis users (three times or more per week) or non-users. The primary outcome measure was the achievement of remission on the evaluations during the 24 months.

Results

Of the 234 participants for whom data was available, 25 (10.7%) were regular cannabis users, and the group comprised significantly more males than females. In the total population, cannabis use was significantly associated with decreased likelihood of remission during the 24-month follow-up period. Subgroup analyses showed that cannabis use was significantly associated with lower remission rates on the Hamilton Depression Rating Scale in females (n=139) and patients prescribed mood stabilizers alone (n=151), whereas in males (n=95) and patients prescribed olanzapine and/or a mood stabilizer (n=83), cannabis use was significantly associated with lower remission rates on the Young Mania Rating Scale. Remission rates were lowest in the concurrent cannabis and tobacco smoking group (n=22) followed by the tobacco smoking only group (n=97), and the non-smoker group (n=116). The post-hoc analysis revealed that all remission rates were significantly lower in the concurrent cannabis and the tobacco smoking group compared to the non-smoker group.

Conclusion

Cannabis use negatively affects the long-term clinical outcome in patients with bipolar spectrum disorders. A comprehensive assessment and integrated management of cannabis use are required to achieve better treatment outcomes for bipolar spectrum disorders.     

Effect of comorbid substance use on neuropsychological performance in subjects with psychotic or mood disorders

Objective - Patients presenting with psychotic or mood disorders present with neuropsychological deficits such as executive and memory disturbance. Deficits of these functions have also been reported in patients presenting with alcohol use or substance use disorders. A large percentage of patients with non-affective psychotic or mood disorders present with a comorbid substance use disorder. These subjects are often a priori excluded from most neuropsychological studies. However, using such an exclusion criterion may induce a selection bias linked to the high prevalence of this dual diagnosis. It is therefore necessary to further explore the impact of substance abuse on neuropsychological performance in subjects with psychotic or mood disorders. Method - Patients consecutively hospitalized for a non-affective psychotic disorder or a mood disorder were included. A standardised method was used to collect information on addictive behaviour, clinical and social characteristics. DSM IV diagnoses, including those of substance use, were made using a structured diagnostic interview and all other available clinical and historical information collected during the hospital stay. Memory performance was tested using the Batterie d'Efficience Mnésique 84 (Battery of memory efficiency 84 items, BEM 84). Executive abilities were explored using the Wisconsin Card Sorting Test (WCST) and the Stroop test. ANCOVAs with cannabis use disorder or alcohol use disorder as main factor were used to examine associations with neuropsychological test scores. Results - We have included 77 patients fulfilling the diagnostic criteria for non-affective psychotic disorders (schizophrenia, schizoaffective disorder, delusional disorder, other psychotic disorder, n=35) or mood disorders (n=42). Among these patients, 27.3% presented with a lifetime history of alcohol abuse/dependence (current prevalence: 14.3%) and 23.4% presented with a lifetime history of cannabis abuse/dependence (current prevalence: 11.7%). We have assessed the specific impact of alcohol and cannabis use on neuropsychological performance. No significant differences on memory and executive performance were found between patients presenting with and without a lifetime history of alcohol abuse/dependence. These results were not modified after adjustement for potential confounding factors (age, gender, educational level, age at onset, diagnosis, current versus past addictive behaviour). Patients with a lifetime history of cannabis abuse/dependence had significantly higher (i.e. better performance) general BEM 84 score (F=3.89, df=1, p=0.05), higher complex figure delayed recall scores (F=6.62, df=1, p=0.01) and higher recognition scores (F=3.9, df=1, p=0.05) than patients presenting without a lifetime history of cannabis use. After adjustment on covariables (age, gender, educational level, age at onset, diagnosis, current versus past addictive behaviour), the differences on memory performance between the two groups were no longer significant, the differences found before adjustment were mainly explained by the confounding effect of age. Patients presenting with a lifetime history of cannabis abuse/dependence had significantly lower interference scores on the Stroop test than subjects without cannabis use (F=5.67, df=1, p=0.02). This finding was not modified after adjustment for confounding factors. Information on substance use was collected by interviewing the patient and was completed by using all other available source of information, but no urine testing was performed. Thus, substance use could have been underestimated or unrecognized in some patients. We did not distinguish patients who presented with substance abuse from those who presented with dependence because there were few of the latter. Distinguishing these two populations would be of interest because dependence may have a more deleterious effect than abuse in neuropsychological performances. Finally, we did not included normal control subjects so we can not assess if our cohort present with memory and executive deficits compared to normal subjects. Conclusion - Comorbid alcohol or cannabis abuse/dependence has limited effects on memory and executive abilities in subjects with psychotic or mood disorder. The only significant difference between subjects with and without a dual diagnosis was that subjects with cannabis use disorder performed poorly on the Stroop test. No other significant difference in executive and memory performance was found after adjustment for confounding factors. Since there is a high prevalence of a comorbid substance use disorder in subjects with psychotic or mood disorder, the exclusion of these patients in neuropsychological studies may not be systematically justified.