Relationship between cannabis and psychosis: Reasons for use and associated clinical variables

Multi-modal and bi-directional effects of a synthetic Δ9-Tetrahydrocannabinol (THC) analogue, Nabilone, on spatio-temporal binding windows: Evidence from the projected hand illusion

Abnormally widened spatial and temporal binding windows (SBW/TBWs; length of space/time whereby stimuli are considered part of the same percept) are observed in schizophrenia. TBW alterations have been associated with altered sense of agency (hereafter referred to as agency), and an associative relationship between embodiment (body ownership) and agency has been proposed. SBWs/TBWs are investigated separately, but no evidence exists of these being separate in mechanism, system or function. The underlying neural substrate of schizophrenia remains unclear. The literature claims either pro-psychotic or anti-psychotic effects of Δ9-Tetrahydrocannabinol (THC) in patients and healthy individuals, but major support for cannabis in the aetiology of schizophrenia is associative, not causal. To clarify if THC is pro- or anti-psychotic, this single-blind, placebo-controlled within-subjects cross-over study tested several hypotheses. 1) Competing hypotheses that a synthetic THC analogue, Nabilone (NAB, 1-2 mg), would alter measures of agency and embodiment in healthy volunteers (n = 32) similarly, or opposite, to that of in patients with schizophrenia. 2) That there would be significant associations between any NAB-induced alterations in individual agency and embodiment measures in the Projected Hand Illusion (PHI). 3) That there is a unitary spatio-temporal binding window (STBW). A large proportion of individuals did not experience the PHI. Multimodal and bi-directional effects of NAB on the PHI were observed. Evidence of a unitary spatio-temporal binding window (STBW) was observed. NAB widened the STBW in some but narrowed it in others as a function of space and delay. No associations were found between agency and embodiment.

Behind the heterogeneity in the long-term course of first-episode psychosis: Different psychotic symptom trajectories are associated with different patterns of cannabis and stimulant use

BACKGROUND

Data-driven classification of long-term psychotic symptom trajectories and identification of associated risk factors could assist treatment planning and improve long-term outcomes in psychosis. However, few studies have used this approach, and knowledge about underlying mechanisms is limited. Here, we identify long-term psychotic symptom trajectories and investigate the role of illness-concurrent cannabis and stimulant use.

METHODS

192 participants with first-episode psychosis were followed up after 10 years. Psychotic symptom trajectories were estimated using growth mixture modeling and tested for associations with baseline characteristics and cannabis and stimulant use during the follow-up (FU) period.

RESULTS

Four trajectories emerged: (1) Stable Psychotic Remission (54.2 %), (2) Delayed Psychotic Remission (15.6 %), (3) Psychotic Relapse (7.8 %), (4) Persistent Psychotic Symptoms (22.4 %). At baseline, all unfavorable trajectories (2-4) were characterized by more schizophrenia diagnoses, higher symptom severity, and longer duration of untreated psychosis. Compared to the Stable Psychotic Remission trajectory, unstable trajectories (2,3) showed distinct associations with cannabis/stimulant use during the FU-period, with dose-dependent effects for cannabis but not stimulants (Delayed Psychotic Remission: higher rates of frequent cannabis and stimulant use during the first 5 FU-years; Psychotic Relapse: higher rates of sporadic stimulant use throughout the entire FU-period). The Persistent Psychosis trajectory was less clearly linked to substance use during the FU-period.

CONCLUSIONS

The risk for an adverse long-term course could be mitigated by treatment of substance use, where particular attention should be devoted to preventing the use of stimulants while the use reduction of cannabis may already yield positive effects.

GAPi: A description of the initiative for early psychosis intervention in Latin America and the short- to medium-term outcomes in early psychosis patients

INTRODUCTION

Schizophrenia is a debilitating disorder that affects a significant proportion of the population and leads to impaired functionality and long-term challenges. The first episode of psychosis (FEP) is a critical intervention stage for improving long-term outcomes. The GAPi program was established in São Paulo, Brazil to provide early intervention services and evaluate biomarkers in individuals with FEP. This article delineates the objectives of the GAPi program, detailing its innovative research protocol, examining the clinical outcomes achieved, and discussing the operational challenges encountered during its initial decade of operation.

METHODS

The study comprised a prospective cohort of antipsychotic-naïve individuals with first-episode psychosis aged between 16 and 35 years. Participants were recruited from a public psychiatric facility in São Paulo. Emphasizing the initiative's commitment to early intervention, clinical assessments were systematically conducted at baseline and at two months, one year, two years, and five years of treatment to capture both short- and medium-term outcomes. Various assessment tools were utilized, including structured interviews, symptom scales, the Addiction Severity Index, and functional assessments.

RESULTS

A total of 232 patients were enrolled in the cohort. Among them, 65.95 % completed the 2-month follow-up. Most patients presented with schizophrenia spectrum disorders, followed by bipolar disorder and major depressive disorder with psychotic features. Treatment response rates and remission rates were evaluated at different time points, with promising outcomes observed. The program also assessed socio-demographic factors, substance use, family history, and genetic and biomarker profiles, providing valuable data for research.

DISCUSSION

The GAPi program has emerged as the largest ongoing cohort of antipsychotic-naïve first-episode psychosis in Latin America, contributing to the understanding of early psychosis in low- and middle-income countries. Despite operational challenges, the program has demonstrated efficacy in reducing the duration of untreated psychosis and in improving clinical outcomes. A multidisciplinary approach, including pharmacological treatment, psychosocial interventions, and family involvement, has been instrumental in enhancing treatment adherence and long-term prognosis.

CONCLUSION

The GAPi program represents a valuable model for early intervention in first-episode psychosis and provides insights into the pathophysiology, treatment, and long-term outcomes of individuals with schizophrenia and related disorders. Continued research and resource allocation are essential for addressing operational challenges and expanding early intervention services in low- and middle-income countries.

Characterization of substance use in homeless patients with mental disorders

BACKGROUND

In Denmark, 42% of homeless people suffer from dual diagnosis, i.e. the co-occurrence of a substance use of alcohol and/or illegal substances and another psychiatric disorder. Dual diagnosis homeless patients often cause differential diagnostic difficulties and fail to receive effective treatment. A solid grasp of the role of substance use in these patients may inform the diagnostic decision and contribute to improve their treatment. Today, knowledge of these issues remains scarce. The purpose of this study was to explore substance use in homeless patients with mental disorders and their subjective perspectives on their substance use.

METHODS

44 homeless dual diagnosis patients were included in the study. They were examined in interviews focusing on their substance use and their subjective perspective on their substance use.

RESULTS

The most frequently used substances were cannabinoids (70.5%) and alcohol (45.5%), followed by cocaine, sedative/hypnotics, and amphetamine. The finding suggests that substance use in dual diagnosis homeless patients is a complex phenomenon with most patients (56.8%) using multiple substances. While substance use seems to contribute to keep the patients homeless, substance use was also reported to play an important role in coping with life on the streets by offering social contact and some relief from a desperate situation.

CONCLUSION

Substance use, mental disorder, and homelessness seem to be closely entangled, reinforcing each other and making it difficult to help these vulnerable patients. Diagnostic overshadowing may cause delays in adequate diagnosis and treatment of this group of patients.

Use of antipsychotic medication, benzodiazepines, and psychiatric hospitalization in cannabis-related versus cannabis-unrelated schizophrenia - a nationwide, register-based cohort study

BACKGROUND

Evidence suggests that cannabis may be a causal factor for development of schizophrenia. We aimed to investigate whether use of antipsychotic medication, benzodiazepines, and psychiatric service use differs among patients with schizophrenia depending on whether psychosis was precipitated by a diagnosis of cannabis use disorder (CUD).

METHODS

We utilized the nationwide Danish registries to identify all individuals with an incident diagnosis of schizophrenia from 1995 to 2016. We also collected information on whether first CUD diagnosis preceded schizophrenia and thus defined a group of potentially cannabis-related schizophrenia. We compared the cannabis-related schizophrenia group both with all non-cannabis-related patients with schizophrenia and with non-cannabis-related patients with schizophrenia that were propensity-score matched to cases using a range of potentially confounding variables.

RESULTS

We included 35 714 people with incident schizophrenia, including 4116 (11.5%) that were cannabis-related. In the unmatched-comparison analyses, there were no clear differences over time in use of antipsychotics and benzodiazepines related to whether the diagnosis of schizophrenia was cannabis-related. After propensity-score matching, use of antipsychotics and benzodiazepines was significantly lower among cannabis-related cases of schizophrenia. In the unmatched comparison, the cannabis-related group had significantly more days admitted than the non-cannabis-related group. This was markedly attenuated after propensity-score matching.

CONCLUSIONS

Our findings indicate the importance of considering cannabis-related cases of schizophrenia as a potentially distinct disorder in terms of prognosis. It is unclear, however, if these differences are due to different biological types of schizophrenia being compared or if they rather indicate behavioral differences such as reduced adherence and treatment-seeking.

Do anxiety symptoms and coping motives serially mediate the association between psychotic-like experiences and cannabis-related problems in undergraduate recent cannabis users?

Many Canadian emerging adults (ages 18-25 years) use cannabis, with 60 % of past-three-month users experiencing one or more cannabis-related problems (i.e., adverse consequences of use). While psychotic-like experiences (PLEs) and cannabis problems overlap, little is known about the mechanisms explaining this link. One hypothesis is that PLEs are distressing and give rise to anxiety, with which emerging adults attempt to cope through increased cannabis use, in turn increasing their risk for cannabis-related problems. We tested a chained-mediational model to determine if anxiety and coping-with-anxiety motives for cannabis use sequentially mediated the link between PLEs and cannabis problems in emerging adult undergraduates; a conditional process model tested for moderation by sex. Emerging adult cannabis users (N = 413; mean [SD] age = 19.1 [1.5] years; 71.9 % female) from five Canadian universities provided cross-sectional, self-report survey data in fall 2021. Validated measures of PLEs, anxiety, cannabis coping-with-anxiety motives, and cannabis-related problems were administered. Path analyses supported the hypothesized chained mediational indirect effect (b = 0.027, 95 % bootstrap CI [0.012, 0.050]). No direct effect was found (p =.698), suggesting that the PLEs-to-cannabis problems association is fully explained by anxiety and cannabis coping-with-anxiety motives. Inconsistent with hypotheses, mediation did not depend on sex (95 % CIs crossed zero); therefore, anxiety and cannabis coping-with-anxiety motives explain the link between PLEs and cannabis problems in emerging adults regardless of their sex. Results highlight anxiety and cannabis coping-with-anxiety motives as potentially important intervention targets in cannabis-using emerging adults with PLEs, possibly preventing the development/worsening of cannabis-related problems.

How to quit cannabis when you have a mental illness: study from the perspective of patients who have successfully quit

AIMS AND METHOD

Research regarding quitting cannabis use often excludes patients with severe mental illness (SMI). We investigated facilitating and impeding factors in SMI patients and their advice to others, using semi-structured interviews with 12 SMI-patients, who were daily cannabis users for ≥12 months and had fully stopped using for ≥6 months.

RESULTS

Seeking distraction, social contacts in personal environment, avoiding temptation and support from professionals were facilitating factors in stopping. Impeding factors were withdrawal symptoms, user environment, experiencing stress and user's routine. Advice to other patients included to just do it, seek support from others, quit 'cold turkey' and acknowledge that cannabis use is a problem. Advice to mental health professionals is to discuss cannabis use from the start of treatment.

CLINICAL IMPLICATIONS

It is important to inform patients that cannabis use has negative consequences and limits the effects of treatment. Do not judge cannabis use or force the patient to stop.

Exploration of cannabis use and polygenic risk scores on the psychotic symptom progression of a FEP cohort

Cannabis use is highly prevalent in first-episode psychosis (FEP) and plays a critical role in its onset and prognosis, but the genetic underpinnings promoting both conditions are poorly understood. Current treatment strategies for cannabis cessation in FEP are clearly inefficacious. Here, we aimed to characterize the association between cannabis-related polygenic risk scores (PRS) on cannabis use and clinical course after a FEP. A cohort of 249 FEP individuals were evaluated during 12 months. Symptom severity was measured with the Positive and Negative Severity Scale and cannabis use with the EuropASI scale. Individual PRS for lifetime cannabis initiation (PRS_CI) and cannabis use disorder (PRS_CUD) were constructed. Current cannabis use was associated with increased positive symptoms. Cannabis initiation at younger ages conditioned the 12-month symptom progression. FEP patients with higher cannabis PRS_CUD reported increased baseline cannabis use. PRS_CI was associated with the course of negative and general symptomatology over follow-up. Cannabis use and symptom progression after a FEP were modulated by cannabis PRS, suggesting that lifetime initiation and use disorders may have partially independent genetic factors. These exploratory results may be the first step to identify those FEP patients more vulnerable to cannabis use and worse outcomes to ultimately develop tailored treatments.

Scoping Review of Cannabis-Reduction Psychosocial Interventions and Reasons for Use among Young Adults with Psychosis

Objective: No evidence-based intervention effectively reduces cannabis use in young adults with psychosis (YAP). To generate hypotheses about why, a scoping review was conducted to synthesize evidence about motivations for cannabis use and reduction/cessation for YAP and the psychosocial interventions trialed to identify possible gaps between motivations and interventive strategies. Methods: A systematic literature search was conducted in December, 2022. Reviews of titles and abstracts (N = 3,216) and full-texts (n = 136) resulted in 46 articles. Results: YAP use cannabis for pleasure, to reduce dysphoria, and for social and recreational reasons; motivations for cessation include insight about cannabis-psychosis interactions, incompatibility with goals and social roles, and support from social networks. Interventions with at least minimal evidence of efficacy include motivational interviewing, cognitive-behavioral strategies, and family skills training. Conclusions: Authors recommend additional research on mechanisms of change and motivational enhancement therapy, behavioral activation, and family-based skills interventions matched to YAP motivations for use/cessation.

First episode psychosis with and without the use of cannabis and synthetic cannabinoids: Psychopathology, global functioning and suicidal ideation and antipsychotic effectiveness

BACKGROUND

Natural Cannabis (NC) and Synthetic Cannabinoids (SCs) use can increase the risk of developing psychotic disorders and exacerbate their course.

AIMS

To examine the differences between psychoses not associated with cannabis use and those associated with NC and SCs use, evaluating psychotic symptoms, global functioning, dissociative symptoms and suicidal ideation.

METHODS

The sample of 61 patients with First Episode Psychosis (FEP) was divided into 3 groups: non-Cannabis users (non-users, N = 20); NC users (THC-users, N = 21); SCs users (SPICE-users, N = 20). Each group was assessed at FEP and after 3 and 9 months through specific psychopathological scales.

RESULTS

THC-users, and even more SPICE-users, displayed much more severe positive symptoms than non-users. Negative symptoms were higher among non-users. After 9 months the non-users had recovered significantly better than SPICE-users in their global functioning. Dissociative symptoms were significantly greater in substance users. Finally, suicidal ideation was higher in SPICE-users than in both THC-users and non-users.

DISCUSSION

The psychoses induced by NC and SCs showed different symptomatic pictures and outcomes from each other and when compared to the psychoses not associated with the use of substances; such knowledge could be relevant in identifying a specific drug treatment.

Substance use Specificities in Women with Psychosis: A Critical Review

BACKGROUND

Women with schizophrenia or other psychotic disorders differ from male patients in many respects, including psychopathology, prognosis, disease course, and substance use comorbidities. Most studies performed to date to investigate the association between drug use and psychosis have not evaluated gender differences, although this has started to change in recent years.

METHODS

We briefly summarize the available evidence on gender differences in drug use and substance use disorders (SUD) in psychotic patients during the early phases of the psychotic illness and during the course of schizophrenia.

RESULTS

Substance use and SUD are both less prevalent in women, both in the general population and at all phases of the psychotic spectrum. Some studies suggest that SUD may be under diagnosed in female patients, in part due to their more vulnerable profile. Substance use, especially cannabis, may more negatively impact females, especially on the disease course and prognosis. The available data suggest that it may be more difficult to treat SUD in female patients with schizophrenia, which could negatively impact prognosis.

CONCLUSION

Women with concomitant psychotic illness and SUD comprise a highly vulnerable subgroup. This should be considered when selecting the treatment approach, especially in the early phases of the illness, to ensure better outcomes.

Comparative Efficacy and Tolerability of Antipsychotics for Juvenile Psychotic Disorders: A Systematic Review and Network Meta-Analysis

BACKGROUND

Psychotic disorders produce important morbidity and disability in children and adolescents. There have been few relevant treatment trials, encouraging assessment of research aimed at testing efficacy and safety of antipsychotics for juveniles. We aimed to compare the short- and long-term efficacy and safety of antipsychotics to treat psychotic disorders among children and adolescents.

METHODS

Four major bibliographic databases (PubMed, MEDLINE, PsycINFO, and EMBASE) were searched for clinical trials of antipsychotics in children or adolescents, from database inception to May 2021. We searched for clinical trials comparing antipsychotics with control conditions for juvenile psychosis based on blinded review by 2 independent investigators (C.S.Y. and M.L.). We adhered to the Preferred Reporting Items for Systematic Reviews and Meta-analyses and applied the Cochrane risk-of-bias tool to appraise study quality. One reviewer (A.B.) performed data abstraction which was confirmed by 2 independent, blinded reviewers (C.S.Y. and M.L.). Primary outcomes were scores rating psychosis symptoms and dichotomized retention in treatment protocols versus dropouts because of adverse events. Effect sizes were pooled using frequentist random-effects network meta-analysis modeling to generate summary rate ratios (RRs) and Cohen d standardized mean differences.

RESULTS

Systematic searching generated 1330 unique records. Of these, short-term (n = 15, for 6 [3-12] weeks) and long-term (n = 10, for 12 [6-60] months) treatment trials involved 2208 (39.2% females; median age, 15.3 years), and 1366 subjects (35.0% females; median age, 15.6 years), respectively. Short-term reduction of psychosis scores ranked clozapine (d = -1.35; 95% confidence interval [CI], -1.97 to -0.73]), molindone (-1.22; 95% CI, -1.68 to -0.75), olanzapine (-1.12; 95% CI, -1.44 to -0.81), and risperidone (-0.93; 95% CI, -1.22 to -0.63) as the most effective agents. In longer-term treatment, only lurasidone was effective. Clozapine (RR, 12.8) and haloperidol (RR, 5.15) led to more all-cause and adverse event-related dropouts. There were few trials/drug (1 each for aripiprazole, asenapine, lurasidone, molindone, paliperidone, and ziprasidone, short term; aripiprazole, clozapine, haloperidol, lurasidone, and molindone, long-term). Heterogeneity and inconsistency were high, especially in long-term trials, without evidence of publication bias.

CONCLUSIONS

Some antipsychotics were effective and tolerated short term, but longer-term evidence was very limited. The overall paucity of trials and of adequate controls indicates that more well-designed randomized controlled trials are required for adequate assessment of antipsychotic drug treatment for juveniles.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42021232937.

Association Between Hormonal Birth Control, Substance Use, and Depression

OBJECTIVE

The current study examined the impact of the use of hormonal birth control, cannabis (CB), and alcohol on depression symptoms.

STUDY DESIGN

Survey data from 3,320 college-aged women collected over a 2-year period. Depression symptoms were assessed using the PHQ-9.

RESULTS

Individuals taking hormonal birth control (N = 998; age = 19.1 ± 1.6 years) had lower overall depression scores than did those not taking birth control (N = 2,322; age = 19.1 ± 1.8 years) with 15.2% of those not taking hormonal birth control had depressive symptoms while 12.1% of those in the birth control group had depressive symptoms. Additionally, those taking hormonal birth control had higher scores on the alcohol and CB use assessment. A between-subjects ANOVA with depression score as the dependent variable found significant effects hormonal birth control use, CB and alcohol use, as well as a significant interaction between CB use and hormonal birth control use.

CONCLUSIONS

While there are some limitations (e.g., the between subjects design makes it such that there may be uncontrolled differences between groups), the results suggest that hormonal birth control use may help to reduce depressive symptoms.

IMPLICATIONS

More studies examining the impact of hormonal birth control and substance use on depression are required. The results suggest a potential interaction between CB and hormonal birth control use on depression symptoms that is not observed for alcohol. This implies that alcohol and CB may be linked to depression via different mechanisms.

Cannabis use disorder and dissociation: A report from a prospective first-episode psychosis study

BACKGROUND

Cannabis is the most used recreational drug worldwide. Its use can increase the risk of developing psychotic disorders and exacerbate their course. However, the relationship between cannabis use and dissociative symptoms has been scarcely investigated.

AIMS

To examine differences in psychotic and dissociative symptoms, and in functioning in first-episode psychotic patients (FEPp) using cannabis compared with those not using cannabis.

METHODS

Between January 2014 and December 2019, seventy FEPp with cannabis use disorder (N = 35) and without it (N = 35) were recruited in psychiatric inpatient facilities in the Italian regions of Lazio and Piemonte. All subjects were assessed at FEP, after 4 and 8 months, using the Positive and Negative Syndrome Scale (PANSS), the Global Assessment of Functioning (GAF) scale and the Dissociative Experiences Scale - II (DES-II). Detailed information on the pattern of cannabis and other substance use were collected.

RESULTS

FEP using cannabis showed higher levels of positive symptomatology, dissociative experiences and worse functioning than their non-user counterpart, despite a comparable antipsychotic treatment. At an eight-month prospective evaluation, FEP using cannabis still showed higher levels of positive symptomatology and dissociation. Moreover, global functioning worsened over time in FEPp using cannabis, whereas it improved those not using it.

DISCUSSION

Our findings suggest that a greater degree of dissociation and positive symptoms at FEPp and their persistence over time may characterise cannabis-associated psychosis. Both these factors might explain the overall functioning worsening over time that we observed in the cannabis-user group compared to the functioning improvement in the non-user group.

Duration of Untreated Disorder and Cannabis Use: An Observational Study on a Cohort of Young Italian Patients Experiencing Psychotic Experiences and Dissociative Symptoms

BACKGROUND

The Duration of Untreated Psychosis (DUP) is the time between the first-episode psychosis (FEP) and the initiation of antipsychotic treatment. It is an important predictor of several disease-related outcomes in psychotic disorders. The aim of this manuscript is investigating the influence of cannabis on the DUP and its clinical correlates.

METHODS

During years 2014-2019, sixty-two FEP patients with and without cannabis use disorder (CUD) were recruited from several Italian psychiatric hospitals. The subjects were then divided into two groups based on the duration of the DUP and assessed at the beginning of the antipsychotic treatment and after 3 and 6 months, using the Positive and Negative Syndrome Scale (PANSS), the Global Assessment of Functioning (GAF) scale, and the Dissociative Experiences Scale (DES-II).

RESULTS

As expected, a longer DUP was associated with worse symptoms and cannabis use did not seem to affect the DUP, but both were related with more dissociative symptoms at onset and over time.

DISCUSSION

According to our study, cannabis use can be a predictor of FEP and DUP, and of disease outcome. However, several factors might influence the relationship between cannabis use and DUP. Preventing cannabis use and early diagnosis of psychotic disorders might impact the disease by reducing the persistence of symptoms and limiting dissociative experiences.

Exploring the relationship between recency and frequency of cannabis use and diminished expression and apathy as two dimensions of negative symptoms in first episode psychosis. A one-year follow-up study

The association between cannabis use and negative symptoms remains unclear because of inconsistent results in existing studies. In this study we aimed to investigate the association between different aspects of cannabis use and 1) diminished expression and 2) apathy as a two-dimensional model of negative symptoms in a sample of 460 participants with first-episode psychosis. Data were collected on relevant clinical and demographic factors including diagnostics and habits of drug use at baseline, with a follow-up assessment after 12-months. We found an association between the frequency of cannabis use two years prior to baseline and the severity of diminished expression and apathy at baseline, while only the association to diminished expression held after controlling for potential clinical and demographic confounders. Frequency of cannabis use at baseline also had a significant effect on the development of diminished expression over the 12-month follow-up period. In conclusion, this study suggests that the frequency of cannabis use contributes to the severity of diminished expression at baseline, and to the progression of diminished expression after 12-months follow-up. Our findings also imply a dose-response relationship between frequency of use and severity of symptoms and add evidence to an association between cannabis use and negative symptoms.

Cannabis and mental health: Prevalence of use and modes of cannabis administration by mental health status

BACKGROUND

Cannabis can have an adverse impact on some mental health conditions, while many consumers report using cannabis to manage or improve mental health. Little data exists on how patterns of cannabis use differ by mental health status. The current study examined the prevalence of cannabis use and modes of cannabis administration among consumers who experienced a mental health condition in the past 12-months.

METHODS

Data came from the International Cannabis Policy Study (Wave 1). Online surveys were conducted from Aug - Oct 2018 with 25,747 respondents aged 16-65, recruited from commercial panels in Canada and the US. Multinomial and binary regression models examined differences in cannabis prevalence and use of nine cannabis product types among those with and without self-reported past 12-month experience of anxiety, depression, PTSD, bipolar disorder, and psychosis.

RESULTS

Respondents with each of the five mental health conditions reported more frequent cannabis use than those without a mental health condition (p < .01). Past 12-month cannabis consumers who experienced mental health conditions were significantly more likely to use the most potent products (solid concentrates, THC vape oils, hash) (p < .05), with fewer differences for dried flower, edibles, and other forms. Patterns of use were similar across specific mental health conditions, with some differences among respondents reporting psychosis and bipolar disorder.

CONCLUSION

Individuals experiencing mental health conditions report more frequent cannabis use and use of more potent product types. These findings highlight the need to target use of specific high potency products in prevention, treatment, and harm reduction among these populations.

Gut Microbiota and Bipolar Disorder: An Overview on a Novel Biomarker for Diagnosis and Treatment

The gut microbiota is the set of microorganisms that colonize the gastrointestinal tract of living creatures, establishing a bidirectional symbiotic relationship that is essential for maintaining homeostasis, for their growth and digestive processes. Growing evidence supports its involvement in the intercommunication system between the gut and the brain, so that it is called the gut-brain-microbiota axis. It is involved in the regulation of the functions of the Central Nervous System (CNS), behavior, mood and anxiety and, therefore, its implication in the pathogenesis of neuropsychiatric disorders. In this paper, we focused on the possible correlations between the gut microbiota and Bipolar Disorder (BD), in order to determine its role in the pathogenesis and in the clinical management of BD. Current literature supports a possible relationship between the compositional alterations of the intestinal microbiota and BD. Moreover, due to its impact on psychopharmacological treatment absorption, by acting on the composition of the microbiota beneficial effects can be obtained on BD symptoms. Finally, we discussed the potential of correcting gut microbiota alteration as a novel augmentation strategy in BD. Future studies are necessary to better clarify the relevance of gut microbiota alterations as state and disease biomarkers of BD.

Prevalence and clinical correlates of substance use disorders in South African Xhosa patients with schizophrenia

PURPOSE

To determine the prevalence of substance use disorders (SUDs) in patients with schizophrenia in a sample from South Africa and compare the clinical and demographic correlates in those with and without co-occurring SUDs.

METHODS

Patients with schizophrenia were interviewed using the Xhosa version SCID-I for DSM-IV. We used logistic regression to determine the predictors of SUDs.

RESULTS

In the total sample of 1420 participants, SUDs occurred in 47.8%, with the most prevalent SUD being cannabis use disorders (39.6%), followed by alcohol (20.5%), methaqualone (6.2%), methamphetamine (4.8%) and other SUDs (cocaine, ecstasy, opioids, 0.6%). Polydrug use occurred in 40%, abuse occurred in 13.5%, and 39.6% had at least one substance dependence diagnosis. Significant predictors of any SUD were younger age (41-55 vs. 21-30: OR = 0.7, 95% CI = 0.5-0.9), male sex (OR = 8.6, 95% CI = 5.1-14.6), inpatient status (OR = 1.7, 95% CI = 1.3-2.1), post-traumatic stress symptoms (OR = 4.6, 95% CI = 1.6-13.3), legal (OR = 3.4, 95% CI = 2.0-5.5) and economic problems (OR = 1.4, 95% CI = 1.0-2.0). Methamphetamine use disorders occurred significantly less often in the Eastern compared to the Western Cape provinces. Inpatient status and higher levels of prior admissions were significantly associated with cannabis and methamphetamine use disorders. Post-traumatic stress symptoms were significantly associated with alcohol use disorders. Anxiety disorders were associated with other SUDs.

CONCLUSION

SUDs occurred in almost half of the sample. It is important for clinicians to identify the presence of SUDs as their presence is associated with characteristics, such as male sex, younger age, inpatient status, more prior hospitalisations, legal and economic problems, PTSD symptoms and anxiety.

[Differential diagnostic distinction between substance-induced and primary psychoses: : Recommendations for general psychiatric and forensic practice]

Substanzinduzierte psychotische Störungen (SIPS) sind häufig und für ca. 25 % der ersten Einweisungen in eine psychiatrische Klinik verantwortlich. Aus klinischer Sicht ist aufgrund ähnlicher psychopathologischer Phänomene die diagnostische Unterscheidung zwischen SIPS und primären (genuinen oder kryptogenen) psychotischen Störungen oft eine Herausforderung. Dieser Umstand wird dadurch erschwert, dass SIPS im Zusammenhang mit Cannabis, Halluzinogenen und Amphetaminen ein erhebliches Risiko des Übergangs in eine primäre psychotische Störung (z. B. Schizophrenie) haben. Im ersten Abschnitt dieser Arbeit werden zunächst zwei exemplarische Fallvignetten aus der allgemeinpsychiatrischen und forensischen Praxis vorgestellt. Danach wird im Sinne einer selektiven Literaturübersicht die Relevanz der differenzialdiagnostischen Unterscheidung beider Störungsbilder aus der Sicht der allgemeinen und forensischen Psychiatrie in Bezug auf Therapie, Prognose und richterliche Entscheidung bezüglich der Unterbringung im Maßregelvollzug (§ 63 vs. § 64 StGB) beleuchtet. Der letzte Abschnitt hat das Ziel, ein strukturiertes Vorgehen zur differenzialdiagnostischen Unterscheidung zwischen SIPS und primären psychotischen Störungen zu erarbeiten. Die in dieser Arbeit dargestellten und diskutierten Konzepte und Befunde sollen klinisch tätigen Psychiatern und Psychologen die Diagnosestellung im allgemeinen und forensischen Kontext erleichtern.

The association of cannabis use with quality of life and psychosocial functioning in psychosis

BACKGROUND

Cannabis use is highly prevalent among people with a psychotic disorder. They often report sociality, coping with unpleasant affect and having positive experiences as important reasons for cannabis use, suggesting that cannabis improves their quality of life (QoL) and psychosocial functioning. However, based on previous studies we hypothesize that cannabis use is negatively associated with long-term subjective QoL and psychosocial functioning in people with a psychotic disorder.

METHODS

We included 2994 people with a psychotic disorder (36.4% female), mean age 44.4 (SD 11.9), mean illness duration 17.2 years (SD 11.1), who participated in two yearly routine outcome assessments between 2014 and 2018 (interval 9-15 months) from the naturalistic PHAMOUS cohort study. Linear regression analyses were used to examine whether first assessment cannabis use was associated with QoL (ManSA) and psychosocial functioning (HoNOS). Changes in outcomes between assessments were analyzed with AN(C)OVA, to examine differences between continuers (n = 255), discontinuers (n = 85), starters (n = 83) and non-users (n = 2571).

RESULTS

At first assessment, 11.4% was using cannabis. They had lower QoL (B = -2.93, p < 0.001) and worse psychosocial functioning (B = 1.03, p = 0.002) than non-users. After one year, changes in QoL and psychosocial functioning were not significantly different between continuers, starters, discontinuers and non-users.

CONCLUSIONS

Cannabis users were less satisfied with their family relations and financial situation and showed more aggressive and disruptive behavior and self-harm than non-users. These differences are likely the result of patients having used cannabis for many years. Starting or discontinuing cannabis did not lead to changes in QoL and psychosocial functioning within one year.

Are psychotic-like experiences related to a discontinuation of cannabis consumption in young adults?

OBJECTIVE

To assess changes in cannabis use in young adults as a function of psychotic-like experiences.

METHOD

Participants were initially recruited at age 14 in high schools for the longitudinal IMAGEN study. All measures presented here were assessed at follow-ups at age 19 and at age 22, respectively. Perceived stress was only assessed once at age 22. Ever users of cannabis (N = 552) gave qualitative and quantitative information on cannabis use and psychotic-like experiences using the Community Assessment of Psychic Experiences (CAPE). Of those, nearly all n = 549 reported to have experienced at least one psychotic experience of any form at age 19.

RESULTS

Mean cannabis use increased from age 19 to 22 and age of first use of cannabis was positively associated with a change in cannabis use between the two time points. Change in cannabis use was not significantly associated with psychotic-like experiences at age 19 or 22. In exploratory analysis, we observed a positive association between perceived stress and the experience of psychotic experiences at age 22.

CONCLUSION

Age of first use of cannabis influenced trajectories of young cannabis users with later onset leading to higher increase, whereas the frequency of psychotic-like experiences was not associated with a change in cannabis use. The observed association between perceived stress and psychotic-like experiences at age 22 emphasizes the importance of stress experiences in developing psychosis independent of cannabis use.

Mental health disorders as cooccuring and predictive factors of psychotic disorders in sexually abused children

BACKGROUND

Little is known about the factors associated with psychosis in sexually abused children. Many factors have been associated with both sexual abuse and psychosis, and some mental health disorders have been identified as implied in the relationship between childhood trauma and psychosis.

OBJECTIVES

This study aims to identify factors cooccurring with psychotic disorders in sexually abused youth and to determine which predict the development of psychosis in this population.

PARTICIPANTS AND SETTING

Children with a corroborated report of sexual abuse (n = 882) at a Child Protection Agency (CPA) between 2000 and 2010 and whose health data could be retrieved from public health databases were selected for this study.

METHODS

A prospective matched-cohort design was used, with administrative databases from a CPA and a public health system. Logistic regressions were performed to determine which mental health diagnoses were associated with, and which predicted, psychotic disorders.

RESULTS

Logistic regressions revealed that personality disorders were significantly associated with psychotic disorders whereas substance misuse disorders and intellectual disability significantly predicted psychotic disorders.

CONCLUSIONS

Psychotic disorders and personality disorders appear concomitantly in sexually abused youth. Having received a substance misuse disorder diagnosis increases the risk of developing a psychotic disorder in sexually abused youth. Health professionals should be aware of those risk factors to help reduce the severity of youth sexual abuse consequences and, ultimately, prevent psychosis.

Cannabinoids and their therapeutic applications in mental disorders

Mental disorders represent a significant public health burden worldwide due to their high prevalence, chronically disabling nature, and substantial impact on quality of life. Despite growing knowledge of the pathological mechanisms that underlie the development of these disorders, a high percentage of patients do not respond to first-line clinical treatments; thus, there is a strong need for alternative therapeutic approaches. During the past half-century, after the identification of the endocannabinoid system and its role in multiple physiological processes, both natural and synthetic cannabinoids have attracted considerable interest as putative medications in pathological conditions such as, but not exclusive to, mental disorders. Here, we provide a summary of cannabinoid effects in support of possible therapeutic applications for major depression, bipolar disorder, anxiety, posttraumatic stress disorder, and schizophrenia. Considering this evidence, highlighted benefits and risks of cannabinoid use in the management of these illnesses require further experimental study.
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The impact of sex and cannabis on clinical features in first-admitted patients with psychosis

There is a scarcity of studies investigating the effect of sex on the clinical and treatment characteristics of first-admitted patients with first-episode psychosis (FEP). The reasons for using cannabis and the effect of cannabis on clinical features have not received enough attention either. We aim therefore, to investigate sex differences in the reasons for cannabis use and to determine the effects of sex, cannabis use and their interaction on clinical variables at admission and at discharge from the inpatient unit. 204 first-admitted FEPs in two inpatient units in Spain were included. The reasons for using cannabis were determined using the Dixon questionnaire. Clinical variables were compared between sexes and between cannabis users and non-users. Cannabis use was more frequent in males, but females were more likely to smoke cannabis to "feel relaxed". There was a main effect of sex on positive psychotic symptoms and antipsychotics dose and an interaction effect of cannabis and sex on global functioning at discharge .Our findings show sex differences in the reasons for cannabis use and in some clinical and treatment characteristics among FEP patients. More studies focusing on gender perspectives are needed to develop more individualized treatments.

Cannabinoids for the treatment of mental disorders and symptoms of mental disorders: a systematic review and meta-analysis

BACKGROUND

Medicinal cannabinoids, including medicinal cannabis and pharmaceutical cannabinoids and their synthetic derivatives, such as tetrahydrocannabinol (THC) and cannabidiol (CBD), have been suggested to have a therapeutic role in certain mental disorders. We analysed the available evidence to ascertain the effectiveness and safety of all types of medicinal cannabinoids in treating symptoms of various mental disorders.

METHODS

For this systematic review and meta-analysis we searched MEDLINE, Embase, PsycINFO, the Cochrane Central Register of Controlled Clinical Trials, and the Cochrane Database of Systematic Reviews for studies published between Jan 1, 1980, and April 30, 2018. We also searched for unpublished or ongoing studies on ClinicalTrials.gov, the EU Clinical Trials Register, and the Australian and New Zealand Clinical Trials Registry. We considered all studies examining any type and formulation of a medicinal cannabinoid in adults (≥18 years) for treating depression, anxiety, attention-deficit hyperactivity disorder (ADHD), Tourette syndrome, post-traumatic stress disorder, or psychosis, either as the primary condition or secondary to other medical conditions. We placed no restrictions on language, publication status, or study type (ie, both experimental and observational study designs were included). Primary outcomes were remission from and changes in symptoms of these mental disorders. The safety of medicinal cannabinoids for these mental disorders was also examined. Evidence from randomised controlled trials was synthesised as odds ratios (ORs) for disorder remission, adverse events, and withdrawals and as standardised mean differences (SMDs) for change in symptoms, via random-effects meta-analyses. The quality of the evidence was assessed with the Cochrane risk of bias tool and Grading of Recommendations, Assessment, Development and Evaluation (GRADE) approach. This study is registered with PROSPERO (CRD42017059372, CRD42017059373, CRD42017059376, CRD42017064996, and CRD42018102977).

FINDINGS

83 eligible studies (40 randomised controlled trials, n=3067) were included: 42 for depression (23 randomised controlled trials; n=2551), 31 for anxiety (17 randomised controlled trials; n=605), eight for Tourette syndrome (two randomised controlled trials; n=36), three for ADHD (one randomised controlled trial; n=30), 12 for post-traumatic stress disorder (one randomised controlled trial; n=10), and 11 for psychosis (six randomised controlled trials; n=281). Pharmaceutical THC (with or without CBD) improved anxiety symptoms among individuals with other medical conditions (primarily chronic non-cancer pain and multiple sclerosis; SMD -0·25 [95% CI -0·49 to -0·01]; seven studies; n=252), although the evidence GRADE was very low. Pharmaceutical THC (with or without CBD) worsened negative symptoms of psychosis in a single study (SMD 0·36 [95% CI 0·10 to 0·62]; n=24). Pharmaceutical THC (with or without CBD) did not significantly affect any other primary outcomes for the mental disorders examined but did increase the number of people who had adverse events (OR 1·99 [95% CI 1·20 to 3·29]; ten studies; n=1495) and withdrawals due to adverse events (2·78 [1·59 to 4·86]; 11 studies; n=1621) compared with placebo across all mental disorders examined. Few randomised controlled trials examined the role of pharmaceutical CBD or medicinal cannabis.

INTERPRETATION

There is scarce evidence to suggest that cannabinoids improve depressive disorders and symptoms, anxiety disorders, attention-deficit hyperactivity disorder, Tourette syndrome, post-traumatic stress disorder, or psychosis. There is very low quality evidence that pharmaceutical THC (with or without CBD) leads to a small improvement in symptoms of anxiety among individuals with other medical conditions. There remains insufficient evidence to provide guidance on the use of cannabinoids for treating mental disorders within a regulatory framework. Further high-quality studies directly examining the effect of cannabinoids on treating mental disorders are needed.

FUNDING

Therapeutic Goods Administration, Australia; Commonwealth Department of Health, Australia; Australian National Health and Medical Research Council; and US National Institutes of Health.

Acute effects of ∆9-tetrahydrocannabinol (THC) on resting state brain function and their modulation by COMT genotype

Cannabis produces a broad range of acute, dose-dependent psychotropic effects. Only a limited number of neuroimaging studies have mapped these effects by examining the impact of cannabis on resting state brain neurophysiology. Moreover, how genetic variation influences the acute effects of cannabis on resting state brain function is unknown. Here we investigated the acute effects of ∆9-tetrahydrocannabinol (THC), the main psychoactive constituent of cannabis, on resting state brain neurophysiology, and their modulation by catechol-methyl-transferase (COMT) Val158Met genotype. Thirty-nine healthy volunteers participated in a pharmacological MRI study, where we applied Arterial Spin Labelling (ASL) to measure perfusion and functional MRI to assess resting state connectivity. THC increased perfusion in bilateral insula, medial superior frontal cortex, and left middle orbital frontal gyrus. This latter brain area showed significantly decreased connectivity with the precuneus after THC administration. THC effects on perfusion in the left insula were significantly related to subjective changes in perception and relaxation. These findings indicate that THC enhances metabolism and thus neural activity in the salience network. Furthermore, results suggest that recruitment of brain areas within this network is involved in the acute effects of THC. Resting state perfusion was modulated by COMT genotype, indicated by a significant interaction effect between drug and genotype on perfusion in the executive network, with increased perfusion after THC in Val/Met heterozygotes only. This finding suggests that prefrontal dopamine levels are involved in the susceptibility to acute effects of cannabis.

Cannabis acute use impacts symptoms and functionality in a cohort of antipsychotic naïve First Episode of Psychosis individuals

Introduction

Cannabis use increases the risk of developing psychosis, and subjects with psychosis are more likely to use cannabis. However, studies on the influence of cannabis on psychotic dimensions, response to treatment, and functional outcomes showed conflicting results. Such heterogeneity may be due the inclusion of patients who were already under treatment, and lack of specificity in evaluations. We investigated whether cannabis use yields distinct symptom profiles and functionality in a cohort of antipsychotic-naïve patients at first episode of psychosis (FEP).

Methods

This research is part of a prospective cohort study performed in Sao Paulo, Brazil. The baseline assessment was completed by 175 individuals, and 99 of them were reassessed in a ten-week follow up. We investigated the relationship between cannabis exposure variables (acute use, lifetime use and age at first use) and outcomes: symptom dimensions and functioning.

Results

Individuals who reported acute use of cannabis had higher excitement symptoms at baseline, higher excitement and positive response rates, but no significant differences at follow-up. Additionally, more days of cannabis use in the last month predicted worse functionality and clinical impression at baseline but not at follow-up.

Discussion

The acute use of cannabis influenced the clinical presentation at our FEP baseline assessment, but did not to influence symptoms or functional outcomes at 10-week follow-up. Additionally, acute cannabis users had a better response for excitement and positive symptoms. Higher excitement symptoms at presentation of FEP should raise concerns of possible acute use of cannabis. Longer follow-up times may elucidate whether the effects on functionality would be more evident later in disease development.

The interaction between cannabis use and the Val158Met polymorphism of the COMT gene in psychosis: A transdiagnostic meta - analysis

BACKGROUND

Neither environmental nor genetic factors are sufficient to predict the transdiagnostic expression of psychosis. Therefore, analysis of gene-environment interactions may be productive.

OBJECTIVE

A meta-analysis was performed using papers investigating the interaction between cannabis use and catechol-O-methyl transferase (COMT) polymorphism Val158Met (COMTVal158Met).

DATA SOURCES

PubMed, Embase, PsychInfo.

STUDY ELIGIBILITY CRITERIA

All observational studies assessing the interaction between COMTVal158Met and cannabis with any psychosis or psychotic symptoms measure as an outcome.

STUDY APPRAISAL AND SYNTHESIS METHODS

A meta-analysis was performed using the Meta-analysis of Observational Studies in Epidemiology guidelines and forest plots were generated. Thirteen articles met the selection criteria: 7 clinical studies using a case-only design, 3 clinical studies with a dichotomous outcome, and 3 studies analysing a continuous outcome of psychotic symptoms below the threshold of psychotic disorder. The three study types were analysed separately. Validity of the included studies was assessed using "A Cochrane Risk of Bias Assessment Tool: for Non-Randomized Studies of Interventions".

RESULTS

For case-only studies, a significant interaction was found between cannabis use and COMTVal158Met, with an OR of 1.45 (95% Confidence Interval = 1.05-2.00; Met/Met as the risk genotype). However, there was no evidence for interaction in either the studies including dichotomous outcomes (B = -0.51, 95% Confidence Interval -1.72, 0.70) or the studies including continuous outcomes (B = -0.04 95% Confidence Interval -0.16-0.08).

LIMITATION

A substantial part of the included studies used the case-only design, which has lower validity and tends to overestimate true effects.

CONCLUSION

The interaction term between cannabis use and COMTVal158Met was only statistically significant in the case-only studies, but not in studies using other clinical or non-clinical psychosis outcomes. Future additional high quality studies might change current perspectives, yet currently evidence for the interaction remains unconvincing.

Marijuana use among adults: Initiation, return to use, and continued use versus quitting over a one-year follow-up period

BACKGROUND

This study examined factors associated with marijuana use initiation among never users, prior-to-past year user who return to use, and users who continue use over a 12-month follow-up period.

METHODS

Two waves (W1 and W2) of the Population Assessment of Tobacco and Health (PATH) Study provided data (N=26,204 aged 18+). Multivariable logistic regression models were used to examine associations of W1 sociodemographic, health/mental health, and other substance use characteristics with W2 use status. As applicable, marijuana initiation age, use frequency, and use problems were also examined.

RESULTS

At W2, 2.36% and 10.42% of W1 never users and prior-to-past year users, respectively, reported having used marijuana, and 72.54% of W1 past-year users reported continued use. Those in the 18-24 age group were most likely to initiate, resume, or continue use. Among never and prior-to-past year users, those who reported more mental health problems at W1 also had greater odds of use at W2. Marijuana initiation and return to use were significantly associated with movement from nonuse to use of other substances. Continued marijuana use, as opposed to quitting, was also associated with other substance use, initiation of marijuana use prior to age 18, weekly or more frequent use (AOR=2.34, 95% CI=1.87-2.93), and use problems (AOR=1.40, 95% CI=1.05-1.85) reported at W1.

CONCLUSIONS

Movement between marijuana nonuse and use was substantial during the 12-month follow-up period. Early intervention to prevent initiation of, return to, and continued marijuana and other substance use, especially among young adults, is needed.

Influence of depressive symptoms on distress related to positive psychotic-like experiences in women

The Community Assessment of Psychic Experiences (CAPE) is an effective instrument for detection of the presence of psychotic symptoms and associated distress in the general population. However, little research has studied distress associated with positive psychotic-like experiences (PLEs). Our aim is to study PLE-related distress using the CAPE. In this study we analysed factors associated with differences in PLE-related distress in a sample of 200 non-clinical participants recruited by snowball sampling. Presence of PLEs and related psychological distress was measured using the CAPE questionnaire. The influence of age, gender, educational level and drug use was studied. In univariate analysis we found that gender and CAPE positive, depressive and negative scores, were associated with CAPE positive distress. Using multiple linear regression, we found that only the effect of gender, and the interaction between frequency of depression and gender, remained statistically significant. In our sample interaction between gender and depressive symptoms is a determining factor in distress associated with positive PLEs. The results of this study may be useful for the implementation of prevention programs.

Cannabinoids therapeutic use: what is our current understanding following the introduction of THC, THC:CBD oromucosal spray and others?

INTRODUCTION

The complexity of the endocannabinoid (eCB) system is becoming better understood and new drivers of eCB signaling are emerging. Modulation of the activities of the eCB system can be therapeutic in a number of diseases. Research into the eCB system has been paralleled by the development of agents that interact with cannabinoid receptors. In this regard it should be remembered that herbal cannabis contains a myriad of active ingredients, and the individual cannabinoids have quite distinct biological activities requiring independent studies. Areas covered: This article reviews the most important current data involving the eCB system in relation to human diseases, to reflect the present (based mainly on the most used prescription cannabinoid medicine, THC/CBD oromucosal spray) and potential future uses of cannabinoid-based therapy. Expert commentary: From the different therapeutic possibilities, THC/CBD oromucosal spray has been in clinical use for approximately five years in numerous countries world-wide for the management of multiple sclerosis (MS)-related moderate to severe resistant spasticity. Clinical trials have confirmed its efficacy and tolerability. Other diseases in which different cannabinoids are currently being investigated include various pain states, Alzheimer's disease, Parkinson's disease, Huntington's disease and epilepsy. The continued characterization of individual cannabinoids in different diseases remains important.

Cannabis and development of dual diagnoses: A literature review

BACKGROUND

The use of cannabis has garnered more attention recently with ongoing efforts at marijuana legalization. The consequences of cannabis use are not clearly understood and remain a concern.

OBJECTIVES

To review the acute and persistent effects of cannabis use and associations with psychiatric disorders.

METHODS

Using Pubmed and PsychInfo, we conducted a narrative review of the literature on cannabis and psychiatric comorbidity using the keywords cannab*, marijuana, schizo*, psychosis, mood, depression, mania, bipolar, and anxiety.

RESULTS

There is substantial evidence of cannabis use leading to other illicit drug use and of an association between cannabis use and psychosis. A few reports suggest an association with bipolar disorder while the association with depression and anxiety disorders is mixed.

CONCLUSIONS

Whenever an association is observed between cannabis use and psychiatric disorders, the relationship is generally an adverse one. Age at the time of cannabis use appears to be an important factor with stronger associations observed between adolescent onset cannabis use and later onset of psychiatric disorders. Additional studies taking into account potential confounds (such as withdrawal symptoms, periods of abstinence, and other substance use) and moderators (such as age of initiation of cannabis use, the amount and frequency of drug use, prior history of childhood maltreatment, and gender) are needed to better understand the psychiatric consequences of cannabis use.

Cannabis use is associated with 3years earlier onset of schizophrenia spectrum disorder in a naturalistic, multi-site sample (N=1119)

BACKGROUND

Patients with schizophrenia spectrum disorders and substance use may have an earlier onset of illness compared to those without substance use. Most previous studies have, however, too small samples to control for confounding variables and the effect of specific types of substances. The present study aimed to examine the relationship between substance use and age at onset, in addition to the influence of possible confounders and specific substances, in a large and heterogeneous multisite sample of patients with schizophrenia spectrum disorders.

METHODS

The patients (N=1119) were recruited from catchment areas in Oslo, Stavanger and Bergen, Norway, diagnosed according to DSM-IV and screened for substance use history. Linear regression analysis was used to examine the relationship between substance use and age at onset of illness.

RESULTS

Patients with substance use (n=627) had about 3years earlier age at onset (23.0years; SD 7.1) than the abstinent group (n=492; 25.9years; SD 9.7). Only cannabis use was statistically significantly related to earlier age at onset. Gender or family history of psychosis did not influence the results.

CONCLUSION

Cannabis use is associated with 3years earlier onset of psychosis.

A clinical comparison of schizophrenia with and without pre-onset cannabis use disorder: a retrospective cohort study using categorical and dimensional approaches

BACKGROUND

A high prevalence of cannabis use disorder has been reported in subjects suffering from schizophrenia, fuelling intense debate about whether schizophrenia with pre-onset cannabis use disorder may be a distinct entity with specific features or whether cannabis use disorder can precipitate schizophrenia in genetically vulnerable subjects.

METHODS

We retrospectively assessed schizophrenia subjects with and without pre-onset cannabis use disorder on the basis of their clinical features, assessed categorically and dimensionally with the operational criteria checklist for psychotic illnesses (OCCPI). We also investigated whether the two groups could be differentiated on the basis of a history of psychiatric disorders in first-degree relatives. A principal component factor analysis of the OCCPI items was used to identify specific symptom dimensions. The relationships between symptom dimensions and cannabis status were analysed by point-biserial correlation analysis to control for sex and age at time of the assessment and illness duration.

RESULTS

One hundred and seventy-one subjects with a diagnosis of schizophrenia were included. Among them, forty-one patients (18.2 % of the sample) had a cannabis use disorder before or at the time of the onset of schizophrenia. We found similar results in symptoms patterns or family history between patients with and without pre-onset cannabis use disorder.

CONCLUSIONS

Our results clearly argue against cannabis-associated schizophrenia being a relevant distinct clinical entity of schizophrenia with specific features.