The impact of cannabis use on clinical outcomes in recent onset psychosis

Clinical and cognitive outcomes in first-episode psychosis: focus on the interplay between cannabis use and genetic variability in endocannabinoid receptors

Introduction

Research data show the impact of the endocannabinoid system on psychosis through its neurotransmission homeostatic functions. However, the effect of the endocannabinoid system genetic variability on the relationship between cannabis use and psychosis has been unexplored, even less in first-episode patients. Here, through a case-only design, we investigated the effect of cannabis use and the genetic variability of endocannabinoid receptors on clinical and cognitive outcomes in first-episode psychosis (FEP) patients.

Methods

The sample comprised 50 FEP patients of European ancestry (mean age (sd) = 26.14 (6.55) years, 76% males), classified as cannabis users (58%) or cannabis non-users. Two Single Nucleotide Polymorphisms (SNP) were genotyped at the cannabinoid receptor type 1 gene (CNR1 rs1049353) and cannabinoid receptor type 2 gene (CNR2 rs2501431). Clinical (PANSS, GAF) and neuropsychological (WAIS, WMS, BADS) assessments were conducted. By means of linear regression models, we tested the main effect of cannabis use and its interaction with the polymorphic variants on the clinical and cognitive outcomes.

Results

First, as regards cannabis effects, our data showed a trend towards more severe positive symptoms (PANSS, p = 0.05) and better performance in manipulative abilities (matrix test-WAIS, p = 0.041) among cannabis users compared to non-users. Second, concerning the genotypic effects, the T allele carriers of the CNR1 rs1049353 presented higher PANSS disorganization scores than CC homozygotes (p = 0.014). Third, we detected that the observed association between cannabis and manipulative abilities is modified by the CNR2 polymorphism (p = 0.022): cannabis users carrying the G allele displayed better manipulative abilities than AA genotype carriers, while the cannabis non-users presented the opposite genotype-performance pattern. Such gene-environment interaction significantly improved the overall fit of the cannabis-only model (Δ-R2 = 8.4%, p = 0.019).

Discussion

Despite the preliminary nature of the sample, our findings point towards the role of genetic variants at CNR1 and CNR2 genes in the severity of the disorganized symptoms of first-episode psychosis and modulating cognitive performance conditional to cannabis use. This highlights the need for further characterization of the combined role of endocannabinoid system genetic variability and cannabis use in the understanding of the pathophysiology of psychosis.

Randomized Laboratory Study of Single-Dose Cannabis, Dronabinol, and Placebo in Patients With Schizophrenia and Cannabis Use Disorder

BACKGROUND AND HYPOTHESIS

Up to 43% of people with schizophrenia have a lifetime cannabis use disorder (CUD). Tetrahydrocannabinol (THC) has been shown to exacerbate psychosis in a dose-dependent manner, but little research has assessed its effects on schizophrenia and co-occurring CUD (SCZ-CUD). In this double-dummy, placebo-controlled trial (total n = 130), we hypothesized that a modest dose of THC would worsen cognitive function but not psychosis.

STUDY DESIGN

Effects of single-dose oral THC (15 mg dronabinol) or smoked 3.5% THC cigarettes vs placebo in SCZ-CUD or CUD-only on positive and negative symptoms of schizophrenia (only for SCZ-CUD), cognition, and drug experiences assessed several hours after drug administration. SCZ-only and healthy control participants were also assessed.

STUDY RESULTS

Drug liking was higher in THC groups vs placebo. Neither smoked THC nor oral dronabinol predicted positive or negative symptom subscale scores 2 and 5 h, respectively, after drug exposure in SCZ-CUD participants. The oral dronabinol SCZ-CUD group, but not smoked THC SCZ-CUD group, performed worse than placebo on verbal learning (B = -9.89; 95% CI: -16.06, -3.18; P = .004) and attention (B = -0.61; 95% CI: -1.00, -0.23; P = .002). Every 10-point increment in serum THC + THCC ng/ml was associated with increased negative symptoms (0.40 points; 95% CI: 0.15, 0.65; P = .001; subscale ranges 7-49) and trends were observed for worse positive symptoms and performance in verbal learning, delayed recall, and working memory.

CONCLUSIONS

In people with SCZ-CUD, a modest single dose of oral THC was associated with worse cognitive functioning without symptom exacerbation several hours after administration, and a THC dose-response effect was seen for negative symptoms.

Characteristics of Cannabis and Opioid Users Among Older U.S. Veterans and Their Health Outcomes: A Longitudinal Perspective

Medical cannabis use among U.S. Veterans has continued to rise. However, data on cannabis use by older Veterans is generally less available. This study aims to understand the characteristics of older Veterans who enrolled in the Medical Cannabis Patient Program in Illinois and analyze their health outcomes and co-use of cannabis and opioids using longitudinal survey data. Overall, participants reported positive outcomes for pain, sleep, and emotional problems because of cannabis use in two survey periods. Approximately, 62% and 85% respondents reported no change in memory and falls, respectively, with only 3% and 1% reporting a negative outcome for the conditions in both surveys. About 20.4% of those who indicated cannabis use only in the initial survey started to co-use opioids in the follow-up survey, while 44.1% of those who indicated the use of both substances in the initial survey reported no longer using opioids in the follow-up survey. However, these changes were not statistically significant (α = 0.05 ) . The logistic regression showed that both clinical and contextual factors affected co-use. In conclusion, older U.S. Veterans may be using cannabis to alleviate their pain and other chronic conditions. More research is needed to understand the effect of cannabis use on reducing or substituting opioids.

Discontinuing cannabis use: Symptomatic and functional outcomes in people with an established psychotic disorder

For people with psychotic disorders, the negative outcomes associated with continuing cannabis use would suggest that discontinuing such use may be beneficial for their symptomatic and functional recovery. However, existing evidence that discontinuation is associated with better clinical outcomes is inconsistent and it remains unclear whether discontinuing use is associated with improvements in outcomes for people with an established psychotic disorder. In this 3-5-year longitudinal study we examined baseline and follow-up symptomatic and functional profiles of 371 people with an established psychotic disorder, comparing those who continued to use cannabis with those who discontinued use after baseline assessment. At follow-up, one third (33.3 %) of baseline cannabis users had discontinued use. Discontinuation was associated with significantly lower odds of past-year hallucinations and a mean improvement in level of functioning (Personal and Social Performance Scale) compared to a decline in functioning in continuing users. No significant differences in severity of negative symptoms were observed. With few longitudinal studies examining symptomatic and functional outcomes for people with established psychotic disorders who continue to use cannabis compared to those who discontinue use, our findings that discontinuing cannabis was associated with significant clinical improvements fill gaps in the evidence-base.

Relationship between patterns of cannabis use and functional and symptomatic trajectories in first-episode psychosis

Cannabis use is common in first-episode psychosis (FEP) but evidence is mixed about the extent to which cannabis use predicts symptoms and functional outcomes among those who seek treatment. This study sought to characterize cannabis use patterns and examine the relationship with clinical outcomes, including interactions with early intervention services (EIS). Data were drawn from the Recovery After an Initial Schizophrenia Episode-Early Treatment Program (RAISE-ETP) study including FEP individuals receiving treatment at sites randomized to provide either EIS (NAVIGATE) or community care (CC). Cannabis use was assessed monthly and symptom and functioning data were collected at baseline, 6, 12, 18, and 24 months. Among the 404 participants enrolled, 334 were classified into four cannabis use groups (consistent, sporadic, stopped, and never users) based on their use during the first year. Consistent and sporadic cannabis users were younger, whereas those who had stopped using were older. Sporadic users had the highest depression and the lowest functioning at baseline and improved less during treatment in negative emotions and intrapsychic foundations (e.g., motivation and sense of purpose) than non-users. However, sporadic users who received NAVIGATE improved more in overall symptoms and functioning than those who received CC. Consistent users did not tend to differ in their trajectories from non-users. Individuals with FEP who use cannabis sporadically showed less clinical improvement than non-users. However, EIS treatment reduced the negative effects of sporadic cannabis use on clinical outcomes. Those who use cannabis sporadically may have unique needs that require attention in EIS.

Pattern of predictive features of continued cannabis use in patients with recent-onset psychosis and clinical high-risk for psychosis

Continued cannabis use (CCu) is an important predictor for poor long-term outcomes in psychosis and clinically high-risk patients, but no generalizable model has hitherto been tested for its ability to predict CCu in these vulnerable patient groups. In the current study, we investigated how structured clinical and cognitive assessments and structural magnetic resonance imaging (sMRI) contributed to the prediction of CCu in a group of 109 patients with recent-onset psychosis (ROP). We tested the generalizability of our predictors in 73 patients at clinical high-risk for psychosis (CHR). Here, CCu was defined as any cannabis consumption between baseline and 9-month follow-up, as assessed in structured interviews. All patients reported lifetime cannabis use at baseline. Data from clinical assessment alone correctly classified 73% (p < 0.001) of ROP and 59 % of CHR patients. The classifications of CCu based on sMRI and cognition were non-significant (ps > 0.093), and their addition to the interview-based predictor via stacking did not improve prediction significantly, either in the ROP or CHR groups (ps > 0.065). Lower functioning, specific substance use patterns, urbanicity and a lack of other coping strategies contributed reliably to the prediction of CCu and might thus represent important factors for guiding preventative efforts. Our results suggest that it may be possible to identify by clinical measures those psychosis-spectrum patients at high risk for CCu, potentially allowing to improve clinical care through targeted interventions. However, our model needs further testing in larger samples including more diverse clinical populations before being transferred into clinical practice.

Cannabis use and clinical outcome in people with first-episode schizophrenia spectrum disorders over 24 months of treatment

Cannabis use is associated with an unfavourable course of illness in schizophrenia, although several factors may confound this association. In this longitudinal study, we explored the influence of cannabis use on baseline symptom severity and treatment outcomes in 98 patients with first-episode schizophrenia spectrum disorders treated with a long acting injectable antipsychotic over 24 months. Using mixed models for repeated measures, we compared visit-wise changes in psychopathology, social and occupational functioning and quality of life between recent/current cannabis users (n=45) and non-users (n=53). There were no significant group by time interactions for any of our outcomes, and with the exception of poorer functionality in cannabis users at baseline, no significant differences in these domains at baseline or month 24. Also, remission rates were similar. However, more cannabis users met our operationally defined relapse criteria compared to non-users, and more frequent cannabis use over the course of treatment, as assessed by positive urine toxicology testing, predicted relapse. Our results suggest that cannabis users do not have poorer treatment response than non-users in terms of symptom reduction over the 24 months of treatment. However, dose-related risk of relapse remains with ongoing cannabis use, possibly by directly reducing the threshold for psychotic breakthrough.

Early onset psychosis and cannabis use: Prevalence, clinical presentation and influence of daily use

Most of the studies examining the impact of cannabis use in first episode psychosis (FEP) have been carried out in samples with adult-onset FEP. Data in persons with early onset psychosis (EOP) is scarce. The aims of the study were: To describe the prevalence of lifetime cannabis use, current use, and daily use in patients with EOP compared to healthy controls. To study the differences in clinical presentation between cannabis users and non-users. To examine the risk of presenting an EOP associated with cannabis use and the effect of doses and age of onset of use. An observational cross-sectional study was performed in 90 EOP cases and 62 healthy controls, aged between 7 and 17 years. Our results show a higher prevalence of lifetime use (p = 0002), current use (p < 0.001), and daily use (p < 0.001) in EOP cases in comparison with healthy controls. Regarding clinical presentation, we did not find significant differences in any subscale of the Positive and Negative Syndrome Scale (PANSS). Non-user patients presented more severe depressive symptoms (p = 0002) and worse social functioning than cannabis users (p = 0026). Compared with subjects who never used cannabis, the risk of an EOP was significantly higher for those with a lifetime use (OR = 2.88, p = 0.002)current use (O.R = 6.09, p < 0001), and especially in those with daily use (O.R = 42.77, p = <0001). We found a higher risk of EOP in patients that have used cannabis before 15 years of age. In conclusion, it is necessary to develop early- detection and specific treatment programs for adolescents with cannabis use.

A systematic review of longitudinal studies investigating the impact of cannabis use in patients with psychotic disorders

Introduction: Research has established a link between cannabis use and adverse psychotic outcomes in psychosis patients. However, we have yet to determine if this relationship is maintained when controlling for important confounding variables. The following systematic review aims to investigate if the association between cannabis use and psychotic outcomes is preserved when accounting for important confounders, and if discontinued use mitigates any potential negative impacts.Areas covered: The authors conducted an exhaustive search of the MEDLINE database and Google Scholar to identify articles pertaining to the systematic review. Thirty-three articles were retained for meeting the eligibility criteria.Expert opinion: The evidence confirms an overarching pattern of negative psychotic outcomes of cannabis intake in psychosis populations, even when accounting for crucial confounders. Psychosis patients should be informed with evidence-based health information regarding the effects of cannabis use. Clinicians should systematically evaluate cannabis intake patterns in psychosis patients and offer intervention services geared toward reducing problematic consumption. Researchers should record confounding factors in a more systematic manner in future longitudinal investigations while paying careful attention to the potency and dose-response effects of the ingested cannabis. Deciders will need to investigate the impact of cannabis regulations on psychosis populations.

Daily use of high-potency cannabis is associated with more positive symptoms in first-episode psychosis patients: the EU-GEI case-control study

BACKGROUND

Daily use of high-potency cannabis has been reported to carry a high risk for developing a psychotic disorder. However, the evidence is mixed on whether any pattern of cannabis use is associated with a particular symptomatology in first-episode psychosis (FEP) patients.

METHOD

We analysed data from 901 FEP patients and 1235 controls recruited across six countries, as part of the European Network of National Schizophrenia Networks Studying Gene-Environment Interactions (EU-GEI) study. We used item response modelling to estimate two bifactor models, which included general and specific dimensions of psychotic symptoms in patients and psychotic experiences in controls. The associations between these dimensions and cannabis use were evaluated using linear mixed-effects models analyses.

RESULTS

In patients, there was a linear relationship between the positive symptom dimension and the extent of lifetime exposure to cannabis, with daily users of high-potency cannabis having the highest score (B = 0.35; 95% CI 0.14-0.56). Moreover, negative symptoms were more common among patients who never used cannabis compared with those with any pattern of use (B = -0.22; 95% CI -0.37 to -0.07). In controls, psychotic experiences were associated with current use of cannabis but not with the extent of lifetime use. Neither patients nor controls presented differences in depressive dimension related to cannabis use.

CONCLUSIONS

Our findings provide the first large-scale evidence that FEP patients with a history of daily use of high-potency cannabis present with more positive and less negative symptoms, compared with those who never used cannabis or used low-potency types.

Symptomatology and neurocognition among first-episode psychosis patients with and without cannabis use in the three months prior to first hospitalization

OBJECTIVE

The nature of associations between recent cannabis use and negative symptoms, positive symptoms, and neurocognitive deficits remains unclear. In a relatively large sample of well-characterized patients with first-episode psychosis, we hypothesized that, compared to first-episode patients without cannabis use in the three months prior to first hospitalization, those having used cannabis would have lesser negative symptoms, greater positive symptoms, and no differences in cognitive functioning. Dose-response relationships were also examined.

METHODS

Between 2008 and 2013, 247 first-episode psychosis patients were assessed during their hospitalization at one of six participating inpatient psychiatric units. Measures included the Longitudinal Substance Use Recall for 12 Weeks instrument, the Scale for the Assessment of Negative Symptoms, the Scale for the Assessment of Positive Symptoms, and the MATRICS Consensus Cognitive Battery (MCCB).

RESULTS

Anhedonia-asociality was significantly lower among those using cannabis in the past three months (10.7±4.6 v. 12.1±4.4, p=.023). Delusions were more severe among those having used cannabis (19.3±8.4 v. 15.9±9.1, p=.005), as was bizarre behavior (p=.01). There were no significant differences between those using and not using cannabis across nine MCCB measures. Correlations between the "dose" of cannabis and all of these measures were not significant.

CONCLUSIONS

Compared to those without cannabis use, those who use cannabis in recent months have lesser anhedonia-asociality, greater delusion and bizarre behavior severity, and no significant differences in neurocognition. Such characterizations could shed light on subgroups of individuals with first-episode psychosis, as well as risk factors for cannabis use in the early course of these disorders.

Coping Strategies in Male Patients under Treatment for Substance Use Disorders and/or Severe Mental Illness: Influence in Clinical Course at One-Year Follow-Up

Coping strategies have an impact on substance use disorders (SUD), relapses, and clinical variables, but knowledge on this area is scarce. We explored the coping strategies used during treatment in patients with dual diagnosis (DD), SUD, and severe mental illness (SMI), and the relation with clinical course and relapses at one-year follow-up. A sample of 223 patients was divided into three groups depending on diagnosis: DD (N = 80; SUD with comorbid schizophrenia or major depressive disorder), SUD only (N = 80), and SMI only (N = 63; schizophrenia or major depressive disorder). MANCOVA analyses reflected differences in self-criticism and problem avoidance, with a higher use of these in the DD and SUD groups. The coping strategies used differed depending on the presence/absence of a SUD, but not depending on psychiatric diagnosis. At one-year follow-up, social support was the only strategy that predicted the presence of relapses in DD patients with schizophrenia (positively), and in SMI patients with major depressive disorder (negatively). Thus, social support was associated with relapses, but the relationship was different depending on psychiatric diagnosis. Further studies should analyze the implications of social support as a coping strategy in different mental disorders, as well as its usefulness in individualized interventions.

Impact of tobacco, alcohol and cannabis use on treatment outcomes among patients experiencing first episode psychosis: Data from the national RAISE-ETP study

AIM

The primary aim of this study was to examine the effect of recent tobacco, alcohol and cannabis use on treatment outcomes among participants experiencing first episode psychosis (FEP).

METHODS

Secondary data analyses were conducted on 404 participants enrolled in the Recovery After an Initial Schizophrenia Episode-Early Treatment Program (RAISE-ETP) study. RAISE-ETP investigated the effectiveness of a coordinated specialty care (CSC) intervention for FEP in community mental health agencies in the United States. Generalized estimating equations were used to examine whether recent tobacco smoking, alcohol, and cannabis use at baseline were associated with illness severity, number of antipsychotic pills missed, psychiatric symptoms and quality of life during the 24-month treatment period, after controlling for duration of untreated psychosis and treatment group.

RESULTS

At baseline, roughly 50% (n = 209) of participants reported recent tobacco, 28% (n = 113) alcohol and 24% (n = 95) cannabis use. Tobacco smokers had higher levels of illness severity (β = .24; P < .005), a higher number of missed pills (β = 2.89; P < .05), higher psychiatric symptoms and lower quality of life during treatment relative to non-smokers. Alcohol users had a higher number of missed pills (β = 3.16; P < .05) during treatment and cannabis users had higher levels of illness severity (β = .18; P < .05) and positive symptoms (β = 1.56; P < .05) relative to non-users.

CONCLUSIONS

Tobacco, alcohol and cannabis use are common in youth seeking treatment for FEP. Tobacco smoking was associated with more negative clinical outcomes. These findings have implications for including interventions targeting these areas of substance use within current CSC models.

Impact of comorbid cannabis use on outcome in first episode psychosis

AIM

Comorbid cannabis abuse is common in patients with early psychosis. Little is known about the effect of stopping cannabis use on positive, negative and depressive symptoms. Few studies have controlled for multiple substance use that may mask the specific role that cannabis plays in symptom outcomes. The aim of this study was to investigate whether course and level of cannabis use negatively impacted early psychosis patient symptom profiles (positive, negative and depressive symptoms) over 24 months.

METHODS

One hundred and ninety-two patients admitted to an early psychosis intervention programme in a naturalistic setting were followed across three time periods: initial presentation, 12 and 24 months. Patients' clinical characteristics (substance use, positive/negative symptoms and depressive symptoms) were assessed at each time period.

RESULTS

There were no significant associations found between cannabis abuse and positive and negative symptoms. Continuation and discontinuation of cannabis use were not significant for cannabis or any other substance when compared to positive and negative symptoms. There was a significant interaction between cannabis and alcohol for depressive symptoms, where depressive symptoms were significantly higher in patients who abused cannabis without co-occurring alcohol abuse when compared to non-cannabis using patients.

CONCLUSION

The current study findings indicate a complex interaction between cannabis and alcohol use in a sample of early psychosis patients across 24 months. More research is needed into the association between ceasing cannabis use and long-term outcome for early psychosis patients. Of particular importance is the interaction between level of cannabis and alcohol use as it is related to symptom outcome in early psychosis patients.

Clinical characteristics of primary psychotic disorders with concurrent substance abuse and substance-induced psychotic disorders: A systematic review

BACKGROUND

Distinguishing between a primary psychotic disorder with concurrent substance abuse (PPD+SA) and a substance-induced psychotic disorder (SIPD) can be diagnostically challenging. We aimed to determine if these two diagnoses are clinically distinct, particularly in relation to psychopathology. In addition, we aimed to examine the specific clinical features of cannabis-induced psychotic disorder (CIPD) as compared to primary psychotic disorder with concurrent cannabis abuse (PPD+CA) and also to SIPD associated with any substance.

METHODS

A systematic review of SIPD literature using Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines.

RESULTS

Using strict inclusion criteria, a total of six studies examining SIPD were included in the review (two of which only considered psychosis induced by cannabis alone). The findings did not reveal many consistent differences in psychopathology. However, we did find that that compared to PPD+SA, individuals with SIPD have a weaker family history of psychotic disorder; a greater degree of insight; fewer positive symptoms and fewer negative symptoms; more depression (only in CIPD) and more anxiety.

CONCLUSION

There remains a striking paucity of information on the psychopathology, clinical characteristics and outcome of SIPD. Our review highlights the need for further research in this area.

Therapeutic potential of medicinal marijuana: an educational primer for health care professionals

With the proposed Canadian July 2018 legalization of marijuana through the Cannabis Act, a thorough critical analysis of the current trials on the efficacy of medicinal marijuana (MM) as a treatment option is necessary. This review is particularly important for primary care physicians whose patients may be interested in using MM as an alternative therapy. In response to increased interest in MM, Health Canada released a document in 2013 for general practitioners (GPs) as an educational tool on the efficacy of MM in treating some chronic and acute conditions. Although additional studies have filled in some of the gaps since the release of the Health Canada document, conflicting and inconclusive results continue to pose a challenge for physicians. This review aims to supplement the Health Canada document by providing physicians with a critical yet concise update on the recent advancements made regarding the efficacy of MM as a potential therapeutic option. An update to the literature of 2013 is important given the upcoming changes in legislation on the use of marijuana. Also, we briefly highlight the current recommendations provided by Canadian medical colleges on the parameters that need to be considered prior to authorizing MM use, routes of administration as well as a general overview of the endocannabinoid system as it pertains to cannabis. Lastly, we outline the appropriate medical conditions for which the authorization of MM may present as a practical alternative option in improving patient outcomes as well as individual considerations of which GPs should be mindful. The purpose of this paper is to offer physicians an educational tool that provides a necessary, evidence-based analysis of the therapeutic potential of MM and to ensure physicians are making decisions on the therapeutic use of MM in good faith.

Demographic and clinical correlates of substance use disorders in first episode psychosis

BACKGROUND

We assessed the prevalence and correlates of lifetime substance use disorders in people with first episode psychosis using the baseline data from the Recovery After an Initial Schizophrenia Episode (RAISE) Early Treatment Program study.

METHODS

Research staff assessed 404 first episode patients at 34 community mental health centers across the United States with the Structured Clinical Interview for DSM-IV for diagnoses of psychotic and substance use disorders. Logistic regression was used to evaluate the relationships between participant characteristics and lifetime substance use disorders, followed with generalized linear mixed-effects regression models to identify unique predictors of lifetime substance use disorders.

RESULTS

Approximately one-third of participants reported recent alcohol use (36.6%) and cannabis use (30.7%), and one half (51.7%) met criteria for any lifetime alcohol or drug use disorder. Lifetime substance use disorders were associated with male gender, White race, higher excited (hyperactivity, mood lability, impulsivity, hostility, and uncooperativeness), psychotic and depressive symptoms, less impaired cognition, and greater perceived stigma. Gender, race, and excited symptoms were the most consistent unique predictors of lifetime substance use disorders found in multivariate analyses.

CONCLUSIONS

Half of first episode psychosis patients have co-occurring substance use disorders, which are associated with both more severe symptoms and greater perceptions of stigma. Programs aiming to serve these patients must have the skills and clinical strategies to help people with these unique characteristics.

The relative prevalence of schizophrenia among cannabis and cocaine users attending addiction services

BACKGROUND

Cannabis and cocaine are the most common illicit drugs for which people are treated in addiction services in Latin America. Much research has suggested that the use of cannabis increases the risk of schizophrenia; there is less evidence concerning cocaine. The aim of the present study was to establish the relative prevalence of schizophrenia in people treated for cannabis use and cocaine use disorders in Chile.

METHODS

A sample of 22,615 people treated for illicit drug use disorders was obtained from a national registry of addiction service users in Chile. Clinical diagnoses were established at admission to substance use treatment programs or at any point during the period of treatment. Prevalence rates of schizophrenia and related disorders, and affective disorders were calculated for the groups of people with cocaine use disorders, and cannabis use disorders. Odds ratios (OR) for schizophrenia and for affective disorders were calculated for cannabis users using the group of people treated for cocaine use disorders as reference category.

RESULTS

The prevalence of schizophrenia and related disorders was 1.1% in those with cocaine use disorders, but 5.2% in those with cannabis use disorders (OR 4.9; p<0.01). The prevalence of affective disorders was 9.3% in cocaine use disorders, and 13.2% in cannabis use disorders (OR 1.5; p<0.01).

CONCLUSIONS

The prevalence of schizophrenia and to a lesser extent affective disorders is higher among people with cannabis use disorder than cocaine use disorder among those attending addiction services.

Specific impact of stimulant, alcohol and cannabis use disorders on first-episode psychosis: 2-year functional and symptomatic outcomes

BACKGROUND

Many studies have concluded that cannabis use disorder (CUD) negatively influences outcomes in first-episode psychosis (FEP). However, few have taken into account the impact of concurrent misuse of other substances.

METHODS

This 2-year, prospective, longitudinal study of FEP patients, aged between 18 and 30 years, admitted to early intervention programs in Montreal, Quebec, Canada, examined the specific influence of different substance use disorders (SUD) (alcohol, cannabis, cocaine, amphetamines) on service utilization, symptomatic and functional outcomes in FEP.

RESULTS

Drugs and alcohol were associated with lower functioning, but drugs had a greater negative impact on most measures at 2-year follow-up. Half of CUD patients and more than 65% of cocaine or amphetamine abusers presented polysubstance use disorder (poly-SUD). The only group that deteriorated from years 1 to 2 (symptoms and functioning) were patients with persistent CUD alone. Outcome was worse in CUD than in the no-SUD group at 2 years. Cocaine, amphetamines and poly-SUD were associated with worse symptomatic and functional outcomes from the 1st year of treatment, persisting over time with higher service utilization (hospitalization).

CONCLUSION

The negative impact attributed to CUD in previous studies could be partly attributed to methodological flaws, like including polysubstance abusers among cannabis misusers. However, our investigation confirmed the negative effect of CUD on outcome. Attention should be paid to persistent cannabis misusers, since their condition seems to worsen over time, and to cocaine and amphetamine misusers, in view of their poorer outcome early during follow-up and high service utilization.

Cannabis use in male and female first episode of non-affective psychosis patients: Long-term clinical, neuropsychological and functional differences

BACKGROUND

Numerous studies show the existence of a high prevalence of cannabis use among patients with psychosis. However, the differences between men and women who debut with a first episode of psychosis (FEP) regarding cannabis use have not been largely explored. The aim of this study was to identify the specific sex factors and differences in clinical evolution associated with cannabis use.

METHOD

Sociodemographic characteristics at baseline were considered in our sample of FEP patients to find differences depending on sex and the use of cannabis. Clinical, functional and neurocognitive variables at baseline, 1-year, and 3-years follow-up were also explored.

RESULTS

A total of 549 patients, of whom 43% (N = 236) were cannabis users, 79% (N = 186) male and 21% (N = 50) female, were included in the study. There was a clear relationship between being male and being a user of cannabis (OR = 5.6). Cannabis users were younger at illness onset. Longitudinal analysis showed that women significantly improved in all three dimensions of psychotic symptoms, both in the subgroup of cannabis users and in the non-users subgroup. Conversely, subgroups of men did not show improvement in the negative dimension. In cognitive function, only men presented a significant time by group interaction in processing speed, showing a greater improvement in the subgroup of cannabis users.

CONCLUSION

Despite knowing that there is a relationship between cannabis use and psychosis, due to the high prevalence of cannabis use among male FEP patients, the results showed that there were very few differences in clinical and neurocognitive outcomes between men and women who used cannabis at the start of treatment compared to those who did not.

Premorbid cannabis use is associated with more symptoms and poorer functioning in schizophrenia spectrum disorder

BACKGROUND

Cannabis use disorder is associated with an earlier age at onset and a more severe outcome of schizophrenia spectrum disorders. The role of cannabis use before the onset of illness (premorbid cannabis use) has not been fully investigated. We here examined how amount and type of premorbid cannabis use was associated with the later course of illness including current substance use, symptoms and level of functioning in schizophrenia spectrum disorder.

METHOD

We used a naturalistic sample of patients with DSM-IV schizophrenia spectrum disorders with a comprehensive history of illness and substance use. Data on premorbid substance use was obtained from comprehensive self-report. The relationship to outcome was investigated using regression models that included current substance use and premorbid functioning.

RESULTS

Pre-schizophrenia cannabis use was significantly associated with more severe psychotic symptoms and impaired functioning. Higher levels of premorbid cannabis use were associated with higher levels of current psychotic symptoms. These associations were independent of current substance use and premorbid functioning. Early use of cannabis (age <17 years) was associated with earlier age at onset of psychosis, independently of potential confounders.

CONCLUSIONS

Pre-psychosis cannabis use affects illness outcome in schizophrenia spectrum disorders, and is associated with lower age at onset of psychosis. These findings of independent negative effects of premorbid cannabis use in schizophrenia suggest that a limitation of the general use of cannabis may have beneficial health effects.

Differential effects of childhood trauma and cannabis use disorders in patients suffering from schizophrenia

BACKGROUND

Childhood trauma (CT) and cannabis use are both environmental and modifier risk factors for schizophrenia. However, little is known about how they interact in schizophrenia. We examined the main effect of each of these two environmental factors on the clinical expression of the disease using a large set of variables, and we tested whether and how cannabis and CT interact to influence the course and the presentation of the illness.

METHODS

A sample of 366 patients who met the DSM-IV-TR criteria for schizophrenia was recruited through the FACE-SCZ (Fondamental Advanced Centre of Expertise - Schizophrenia) network. Patients completed a large standardized clinical evaluation including Structured Clinical Interview for DSM Disorders-I (SCID-I), Positive and Negative Symptoms Scale (PANSS), Columbia-Suicide Severity Rating Scale (C-SSRS), Global Assessment of Functioning (GAF), Short-Quality of Life-18 (S-QoL-18), and Medication Adherence Rating Scale (MARS). We assessed CT with the Childhood Trauma Questionnaire and cannabis status with SCID-I.

RESULTS

CT significantly predicted the number of hospitalizations, GAF, and S-QoL-18 scores, as well as the PANSS total, positive, excitement, and emotional distress scores. Cannabis use disorders significantly predicted age of onset, and MARS. There was no significant interaction between CT and cannabis use disorders. However, we found evidence of a correlation between these two risk factors.

CONCLUSIONS

CT and cannabis both have differential deleterious effects on clinical and functional outcomes in patients with schizophrenia. Our results highlight the need to systematically assess the presence of these risk factors and adopt suitable therapeutic interventions.

Substance Use Disorders and Schizophrenia

Substance use disorders are prevalent co-occurring problems among people with schizophrenia, with lifetime rates approaching 80% in this population when tobacco use is taken into account. Substance use disorders are associated with significant adverse effects among people with schizophrenia, including worse psychiatric symptoms, lower functioning, and increased medical morbidity and mortality compared with schizophrenia patients without co-occurring substance use. The etiology of this relationship is multifactorial, involving neurobiological, genetic, and environmental factors. The substances most commonly used by people with schizophrenia are tobacco, alcohol, cannabis, and cocaine. Screening, diagnosis, and treatment of substance use disorders are important and can have significant effects on clinical outcomes. Treatments for comorbid disorders include psychopharmacological, psychotherapeutic, and multidisciplinary interventions. Several medications have been approved by the U.S. Food and Drug Administration for the treatment of substance use disorders, which also appear to be helpful for patients with schizophrenia, although few controlled trials have been conducted specifically in this population. Psychosocial and psychological interventions have been adapted for use among patients with schizophrenia as well. Treatment of both psychotic illness and substance use disorders in an integrated way improves functional and clinical outcomes.

Metabolic syndrome in people with a psychotic illness: is cannabis protective?

BACKGROUND

Rates of the metabolic syndrome in people with psychotic illness are high. Emerging evidence suggests that cannabis use may have a positive impact on cardiometabolic risk factors in the general population, but little is known about its impact for people with psychotic illness. Our aim was to investigate whether the rate of the metabolic syndrome in people with psychotic illness was associated with frequency of cannabis use.

METHOD

The 2010 Australian psychosis survey used a two-phase design to randomly select a nationally representative sample of 1825 adults with psychotic illness for interview and physical assessment. This study is based on 1813 participants who provided data on cannabis use. Multiple logistic regression was used to model the influence of frequency of cannabis use on the metabolic syndrome, adjusting for potential covariates including antipsychotic medication use, smoking, alcohol use and cognitive function.

RESULTS

One-third (33.0%) of participants had used cannabis in the past year. The proportion of non-users, occasional users and frequent users with the metabolic syndrome was 63.0, 51.7 and 43.5%, respectively (p < 0.001). In unadjusted analyses, both occasional use and frequent cannabis use were associated with significantly lower odds of the metabolic syndrome. In the adjusted analyses, the association between the metabolic syndrome and frequent cannabis use remained significant [odds ratio = 0.56, 95% confidence interval (CI) 0.39-0.80], but not the association with occasional use (odds ratio = 0.75, 95% CI 0.49-1.13).

CONCLUSIONS

While cannabis use may be detrimental for mental health, these data suggest that it may also have a cardiometabolic protective effect. Further investigation is required to understand the mechanism underlying this paradoxical finding.

Recommendations for the optimal care of patients with recent-onset psychosis in the Asia-Pacific region

Providing optimal care to patients with recent-onset psychosis can improve outcomes and reduce relapse. However, there is a lack of consistency of the implementation of guidelines for such patients across the Asia-Pacific region. We determined a pragmatic set of recommendations for use on a day-to-day basis to help provide optimal care at this crucial stage of illness. The recommendations were developed over a series of meetings by an international faculty of 15 experts from the Asia-Pacific region, Europe, and South Africa. A structured search of the PubMed database was conducted. This was further developed based on the faculty's clinical experience and knowledge of the literature into 10 key aspects of optimal care for patients during the first five years of a diagnosis of a psychotic disorder, with particular relevance to the Asia-Pacific region. Several common principles emerged: adherence to antipsychotic medications is crucial; substance abuse, psychiatric and medical comorbidities should be addressed; psychosocial interventions play a pivotal role; and family members can play a vital role in overall patient care. By following these recommendations, clinicians may improve outcomes for patients with recent-onset psychosis.

Association of cannabis use with hospital admission and antipsychotic treatment failure in first episode psychosis: an observational study

OBJECTIVE

To investigate whether cannabis use is associated with increased risk of relapse, as indexed by number of hospital admissions, and whether antipsychotic treatment failure, as indexed by number of unique antipsychotics prescribed, may mediate this effect in a large data set of patients with first episode psychosis (FEP).

DESIGN

Observational study with exploratory mediation analysis.

SETTING

Anonymised electronic mental health record data from the South London and Maudsley NHS Foundation Trust.

PARTICIPANTS

2026 people presenting to early intervention services with FEP.

EXPOSURE

Cannabis use at presentation, identified using natural language processing.

MAIN OUTCOME MEASURES

admission to psychiatric hospital and clozapine prescription up to 5 years following presentation.

MEDIATOR

Number of unique antipsychotics prescribed.

RESULTS

Cannabis use was present in 46.3% of the sample at first presentation and was particularly common in patients who were 16-25, male and single. It was associated with increased frequency of hospital admission (incidence rate ratio 1.50, 95% CI 1.25 to 1.80), increased likelihood of compulsory admission (OR 1.55, 1.16 to 2.08) and greater number of days spent in hospital (β coefficient 35.1 days, 12.1 to 58.1). The number of unique antipsychotics prescribed, mediated increased frequency of hospital admission (natural indirect effect 1.09, 95% CI 1.01 to 1.18; total effect 1.50, 1.21 to 1.87), increased likelihood of compulsory admission (natural indirect effect (NIE) 1.27, 1.03 to 1.58; total effect (TE) 1.76, 0.81 to 3.84) and greater number of days spent in hospital (NIE 17.9, 2.4 to 33.4; TE 34.8, 11.6 to 58.1).

CONCLUSIONS

Cannabis use in patients with FEP was associated with an increased likelihood of hospital admission. This was linked to the prescription of several different antipsychotic drugs, indicating clinical judgement of antipsychotic treatment failure. Together, this suggests that cannabis use might be associated with worse clinical outcomes in psychosis by contributing towards failure of antipsychotic treatment.

Continued versus discontinued cannabis use in patients with psychosis: a systematic review and meta-analysis

BACKGROUND

Although the link between cannabis use and development of psychosis is well established, less is known about the effect of continued versus discontinued cannabis use after the onset of psychosis. We aimed to summarise available evidence focusing on the relationship between continued and discontinued cannabis use after onset of psychosis and its relapse.

METHODS

In this systematic review and meta-analysis, we searched MEDLINE for articles published in any language from the database inception date up until April 21, 2015 that included a sample of patients with a pre-existing psychotic disorder with a follow-up duration of at least 6 months. We used a combination of search terms for describing cannabis, the outcome of interest (relapse of psychosis), and the study population. We excluded studies if continued cannabis use or discontinued cannabis use could not be established. We compared relapse outcomes between those who continued (CC) or discontinued (DC) cannabis use or were non-users (NC). We used summary data (individual patient data were not sought out) to estimate Cohen's d, which was entered into random effects models (REM) to compare CC with NC, CC with DC, and DC with NC. Meta-regression and sensitivity analyses were used to address the issue of heterogeneity.

FINDINGS

Of 1903 citations identified, 24 studies (16 565 participants) met the inclusion criteria. Independent of the stage of illness, continued cannabis users had a greater increase in relapse of psychosis than did both non-users (dCC-NC=0·36, 95% CI 0·22-0·50, p<0·0001) and discontinued users (dCC-DC=0·28, 0·12-0·44, p=0·0005), as well as longer hospital admissions than non-users (dCC-NC=0·36, 0·13 to 0·58, p=0·02). By contrast, cannabis discontinuation was not associated with relapse (dDC-NC=0·02, -0·12 to 0·15; p=0·82). Meta-regression suggested greater effects of continued cannabis use than discontinued use on relapse (dCC-NC=0·36 vs dDC-NC=0·02, p=0·04), positive symptoms (dCC-NC=0·15 vs dDC-NC=-0·30, p=0·05) and level of functioning (dCC-NC=0·04 vs dDC-NC=-0·49, p=0·008) but not on negative symptoms (dCC-NC=-0·09 vs dDC-NC=-0·31, p=0·41).

INTERPRETATION

Continued cannabis use after onset of psychosis predicts adverse outcome, including higher relapse rates, longer hospital admissions, and more severe positive symptoms than for individuals who discontinue cannabis use and those who are non-users. These findings point to reductions in cannabis use as a crucial interventional target to improve outcome in patients with psychosis.

FUNDING

UK National Institute of Health Research.

Cannabinoids and Schizophrenia: Risks and Therapeutic Potential

A convergence of evidence shows that use of Cannabis sativa is associated with increased risk of developing psychotic disorders, including schizophrenia, and earlier age at which psychotic symptoms first manifest. Cannabis exposure during adolescence is most strongly associated with the onset of psychosis amongst those who are particularly vulnerable, such as those who have been exposed to child abuse and those with family histories of schizophrenia. Schizophrenia that develops after cannabis use may have a unique clinical phenotype, and several genetic polymorphisms may modulate the relationship between cannabis use and psychosis. The endocannabinoid system has been implicated in psychosis both related and unrelated to cannabis exposure, and studying this system holds potential to increase understanding of the pathophysiology of schizophrenia. Anandamide signaling in the central nervous system may be particularly important. Δ(9)-Tetrahydrocannabinol in cannabis can cause symptoms of schizophrenia when acutely administered, and cannabidiol (CBD), another compound in cannabis, can counter many of these effects. CBD may have therapeutic potential for the treatment of psychosis following cannabis use, as well as schizophrenia, possibly with better tolerability than current antipsychotic treatments. CBD may also have anti-inflammatory and neuroprotective properties. Establishing the role of CBD and other CBD-based compounds in treating psychotic disorders will require further human research.