Several hypotheses may explain the association between substance use, posttraumatic stress disorder (PTSD), and depression. However, few studies have utilized a large multisite dataset to understand this complex relationship. Our study assessed the relationship between alcohol and cannabis use trajectories and PTSD and depression symptoms across 3 months in recently trauma-exposed civilians.

In total, 1618 (1037 female) participants provided self-report data on past 30-day alcohol and cannabis use and PTSD and depression symptoms during their emergency department (baseline) visit. We reassessed participant's substance use and clinical symptoms 2, 8, and 12 weeks posttrauma. Latent class mixture modeling determined alcohol and cannabis use trajectories in the sample. Changes in PTSD and depression symptoms were assessed across alcohol and cannabis use trajectories via a mixed-model repeated-measures analysis of variance.

Three trajectory classes (low, high, increasing use) provided the best model fit for alcohol and cannabis use. The low alcohol use class exhibited lower PTSD symptoms at baseline than the high use class; the low cannabis use class exhibited lower PTSD and depression symptoms at baseline than the high and increasing use classes; these symptoms greatly increased at week 8 and declined at week 12. Participants who already use alcohol and cannabis exhibited greater PTSD and depression symptoms at baseline that increased at week 8 with a decrease in symptoms at week 12.

Our findings suggest that alcohol and cannabis use trajectories are associated with the intensity of posttrauma psychopathology. These findings could potentially inform the timing of therapeutic strategies.

Childhood adversity and cannabis use are considered independent risk factors for psychosis, but whether different patterns of cannabis use may be acting as mediator between adversity and psychotic disorders has not yet been explored. The aim of this study is to examine whether cannabis use mediates the relationship between childhood adversity and psychosis.

Data were utilised on 881 first-episode psychosis patients and 1231 controls from the European network of national schizophrenia networks studying Gene–Environment Interactions (EU-GEI) study. Detailed history of cannabis use was collected with the Cannabis Experience Questionnaire. The Childhood Experience of Care and Abuse Questionnaire was used to assess exposure to household discord, sexual, physical or emotional abuse and bullying in two periods: early (0–11 years), and late (12–17 years). A path decomposition method was used to analyse whether the association between childhood adversity and psychosis was mediated by (1) lifetime cannabis use, (2) cannabis potency and (3) frequency of use.

The association between household discord and psychosis was partially mediated by lifetime use of cannabis (indirect effect coef. 0.078, s.e. 0.022, 17%), its potency (indirect effect coef. 0.059, s.e. 0.018, 14%) and by frequency (indirect effect coef. 0.117, s.e. 0.038, 29%). Similar findings were obtained when analyses were restricted to early exposure to household discord.

Harmful patterns of cannabis use mediated the association between specific childhood adversities, like household discord, with later psychosis. Children exposed to particularly challenging environments in their household could benefit from psychosocial interventions aimed at preventing cannabis misuse.

While cannabis use is a well-established risk factor for psychosis, little is known about any association between reasons for first using cannabis (RFUC) and later patterns of use and risk of psychosis.

We used data from 11 sites of the multicentre European Gene-Environment Interaction (EU-GEI) case–control study. 558 first-episode psychosis patients (FEPp) and 567 population controls who had used cannabis and reported their RFUC.

We ran logistic regressions to examine whether RFUC were associated with first-episode psychosis (FEP) case–control status. Path analysis then examined the relationship between RFUC, subsequent patterns of cannabis use, and case–control status.

Controls (86.1%) and FEPp (75.63%) were most likely to report ‘because of friends’ as their most common RFUC. However, 20.1% of FEPp compared to 5.8% of controls reported: ‘to feel better’ as their RFUC (χ2 = 50.97; p < 0.001). RFUC ‘to feel better’ was associated with being a FEPp (OR 1.74; 95% CI 1.03–2.95) while RFUC ‘with friends’ was associated with being a control (OR 0.56; 95% CI 0.37–0.83). The path model indicated an association between RFUC ‘to feel better’ with heavy cannabis use and with FEPp-control status.

Both FEPp and controls usually started using cannabis with their friends, but more patients than controls had begun to use ‘to feel better’. People who reported their reason for first using cannabis to ‘feel better’ were more likely to progress to heavy use and develop a psychotic disorder than those reporting ‘because of friends’.

A dysbalance of the immune system in psychotic disorders has been well investigated. However, despite a higher prevalence of cannabis (THC) consumption in patients with psychosis, few studies have investigated the impact of this use on inflammatory markers.

One hundred and two inpatients were included in this retrospective study. Leukocytic formula, hsCRP, fibrinogen levels and urinary THC were measured, and comparisons were performed at baseline and after 4 weeks of cannabis cessation between cannabis users (THC+) and non-users (THC−).

After cannabis cessation, we found a greater increase in leucocyte level (p < 0.01), monocyte level (p = 0.05) and a statistical trend to a highest increase of lymphocyte level (p = 0.06) between baseline and 4 weeks in the THC+ group as compared to the THC− group. At 4 weeks, highest leucocyte (p = 0.03), lymphocyte (p = 0.04) and monocyte (p < 0.01) counts were found in the THC+ group, whereas at baseline no difference was found. A positive correlation was found between monocyte count at 4 weeks and baseline Positive and Negative Syndrome Scale (PANSS) negative subscore (p = 0.045) and between the variation of monocyte count between baseline and 4 weeks and the PANSS total score at 4 weeks (p = 0.05).

THC cessation is associated with an increase in inflammatory markers, including white blood cell, lymphocyte and monocyte levels, which correlates with symptomatology of patients with psychosis.

We present the case of a 33-year old man that suffer chronic cocaine and cannabis use since adolescence and at age of 25 develops depressive symptoms and later psychotic symptoms not congruent with mood state. He met criteria for schizoaffective disorder at that moment and was treated with antidepressants and antipsychotic drugs, improving symptomatology even without stopping completely substance use.

To study the relationship between schizoaffective disorder and cannabis and cocaine use, including the neurobiological disturbance secondary to these drugs that can lead to the development of this disorder and the relevance of diagnosing it in context of active substance use.

We carried out a literature review of scientific papers in Medline data base. We used the following terms: “Schizoaffective disorder” “cocaine use” and “cannabis use”. We considered English and Spanish papers for the last 5 years.

After 4 months of cocaine withdrawal and 1 month of cannabis withdrawal, the patient progressively improved depressive and positive psychotic symptoms. However, we reported the persistence of negative symptoms as psychomotor slowdown and cognitive and affective flattening.

The use of cocaine and cannabis is related to depressive and psychotic symptoms in intoxication and can also precipitate chronic psychotic and affective disorders. Induced schizoaffective disorder has not been widely described in literature. Our patient could be a case of schizoaffective induced disorder, but we should consider other pathogenic factors, differential diagnosis and clinical evolution in permanent withdrawal to confirm this diagnosis.

No significant relationships.

Neurocognitive deficits amongst patients with schizophrenia are considered one of schizophrenia’s central features. These deficits appear to be present from the first episode of psychosis (FEP) and certain cognitive impairments could be components of a genetic vulnerability to schizophrenia. Regarding research on cannabis and cognition in schizophrenia, different studies have assessed neurocognitive functions: memory, attention/vigilance, processing speed, verbal learning, executive functions, and verbal fluency.

The aim is to do a review of recent findings concerning the association of cannabis use with cognition in schizophrenia.

A literature review was conducted using the PubMed search database.

Patients with schizophrenia and concomitant cannabis use are associated with worse performance in immediate verbal learning, and in some studies with worse working memory performance. There is an improvement of verbal memory when they cease the cannabis’ consumption. Regarding attention capacity and memory types assessed, the results are controversial. In FEP, heavy cannabis use during the previous year correlates with slower processing speed. Also, FEP-patients with cannabis use but no family history of psychosis perform worse in executive functions, while those with a family history of psychosis perform better.

The studies of psychosis, cannabis and cognition differ in relevant aspects, which might be connected to the result variability. Therefore, before solid conclusions can be reached, it is important to carry out longitudinal studies to understand the changes in the cognitive variables, which can depend on the pattern of cannabis’ use (concurrent or prior to the FEP). Possible confounding variables that might be present should be acknowledged.

No significant relationships.

It remains unclear whether substance use in youth could be associated with a lower likelihood of accessing employment.

To examine prospectively associations between substance use and the risk of not getting employed among young people.

From the French population-based CONSTANCES cohort, 2,873 students who never worked were included between 2012 and 2018 and followed-up for 2.7 years in average. Generalized estimating equations computed the odds of being unemployed versus employed according to substance use at baseline controlling for sociodemographic factors and depressive state. Tobacco use (smoking status and number of cigarettes), cannabis use frequency, and at-risk alcohol use according to the Alcohol Use Disorder Identification Test (total score >7) were introduced separately in the models.

Tobacco use wasn’t significantly associated with employment. Cannabis use at least weekly, and at-risk alcohol use, were associated with increased odds of being unemployed (OR=1.85, 95%CI(1.29, 2.64)) and OR=1.34, 95%CI(1.04, 1.71)), respectively. Additional analyses on sub-scores of alcohol use suggested that the association was mainly driven by alcohol dependence rather than frequency of use.

Public health campaigns must target youth by advising them of the detrimental roles of regular cannabis use and at-risk alcohol use and their lower chances of getting employed.

No significant relationships.

Epidemiological studies show a dose–response association between cannabis use and the risk of psychosis. This review aimed to determine whether there are identifiable risk-thresholds between the frequency of cannabis use and psychosis development.

Systematic search of Embase, MEDLINE, PsycINFO, CINAHL, and Web of Science for relevant studies (1 January 2010–26 April 2021). Case–control or cohort studies that investigated the relationship between cannabis use and the risk of psychosis development that reported effect estimates [odds ratios (OR), hazard ratios (HR), risk ratios (RR)] or the raw data to calculate them, with information on the frequency of cannabis consumption were included. Effect estimates were extracted from individual studies and converted to RR. Two-stage dose–response multivariable meta-analytic models were utilized and sensitivity analyses conducted. The Newcastle Ottawa Scale was used to assess the risk of bias of included studies.

Ten original (three cohorts, seven case–control) studies were included, including 7390 participants with an age range of 12–65 years. Random-effect model meta-analyses showed a significant log-linear dose–response association between cannabis use frequency and psychosis development. A restricted cubic-splines model provided the best fit for the data, with the risk of psychosis significantly increasing for weekly or more frequent cannabis use [RR = 1.01, 95% confidence interval (CI) 0.93–1.11 yearly; RR = 1.10, 95% CI 0.97–1.25 monthly; RR = 1.35, 95% CI 1.19–1.52 weekly; RR = 1.76, 95% CI 1.47–2.12 daily]

Individuals using cannabis frequently are at increased risk of psychosis, with no significant risk associated with less frequent use. Public health prevention messages should convey these risk-thresholds, which should be refined through further work.

Prevention of violent behaviors (VB) in the early phase of psychosis (EPP) is a real challenge. Impulsivity was shown to be strongly related to VB, and different evolutions of impulsivity were noticed along treatments. One possible variable involved in the relationship between VB and the evolution of impulsivity is cannabis use (CU). The high prevalence of CU in EPP and its relationship with VB led us to investigate: 1/the impact of CU and 2/the impact of early CU on the evolution of impulsivity levels during a 3-year program, in violent and non-violent EPP patients.

178 non-violent and 62 violent patients (VPs) were followed-up over a 3 year period. Age of onset of CU was assessed at program entry and impulsivity was assessed seven times during the program. The evolution of impulsivity level during the program, as a function of the violent and non-violent groups of patients and CU precocity were analyzed with linear mixed-effects models.

Over the treatment period, impulsivity level did not evolve as a function of the interaction between group and CU (coef. = 0.02, p = 0.425). However, when including precocity of CU, impulsivity was shown to increase significantly only in VPs who start consuming before 15 years of age (coef. = 0.06, p = 0.008).

The precocity of CU in VPs seems to be a key variable of the negative evolution of impulsivity during follow-up and should be closely monitored in EPP patients entering care since they have a higher risk of showing VB.

Evidence suggests that environmental factors not only increase psychosis liability but also influence the prognosis and outcomes of psychotic disorders. We investigated temporal and cross-sectional associations of a weighted score of cumulative environmental liability for schizophrenia – the exposome score for schizophrenia (ES-SCZ) – with functioning in first-episode psychosis (FEP).

Data were derived from the baseline and 1-month assessments of the Athens FEP Research Study that enrolled 225 individuals with FEP. The Global Assessment of Functioning (GAF) and the Personal and Social Performance Scale (PSP) were used to measure social, occupational, and psychological functioning. The ES-SCZ was calculated based on the previously validated method.

ES-SCZ was associated with the total scores of GAF and PSP at baseline and 1-month assessments. These findings remained significant when accounting for several associated alternative explanatory variables, including other environmental factors (obstetric complications, migration, ethnic minority), clinical characteristics (duration of untreated psychosis, symptom severity, previous antipsychotic use), and family history of psychosis, demonstrating that the association between ES-SCZ and functioning is over and above other risk factors and cannot be explained by symptom severity alone. Functioning improved from baseline to 1-month assessment, but no significant ES-SCZ-by-time interaction was found on functioning, indicating that functioning changes were not contingent on ES-SCZ.

Our findings suggest that rather than a predictor of functional improvement, ES-SCZ represents a stable severity indicator that captures poor functioning in early psychosis. Environmental risk loading for schizophrenia (ES-SCZ) can be beneficial for clinical characterization and incorporated into transdiagnostic staging models.

Cannabis use is a global public health issue associated with increased risks of developing mental health disorders, especially in young people. We aimed to investigate the relationships between cannabis exposure and risks of receiving mental illness diagnoses or treatment as outcomes.

A population based, retrospective, open cohort study using patients recorded in ‘IQVIA medical research data’, a UK primary care database. Read codes were used to confirm patients with recorded exposure to cannabis use who were matched up to two unexposed patients. We examined the risk of developing three categories of mental ill health: depression, anxiety or serious mental illness (SMI).

At study entry, the exposed cohort had an increased likelihood of having experienced mental ill health [odds ratio (OR) 4.13; 95% confidence interval (CI) 3.99–4.27] and mental ill health-related prescription (OR 2.95; 95% CI 2.86–3.05) compared to the unexposed group. During the study period we found that exposure to cannabis was associated with an increased risk of developing any mental disorder [adjusted hazard ratio (aHR) 2.73; 95% CI 2.59–2.88], also noted when examining by subtype of disorder: anxiety (aHR 2.46; 95% CI 2.29–2.64), depression (aHR 2.34; 95% CI 2.20–2.49) and SMI (aHR 6.41; 95% CI 5.42–7.57). These results remained robust in sensitivity analyses.

These findings point to the potential need for a public health approach to the management of people misusing cannabis. However, there is a gross under-recording of cannabis use in GP records, as seen by the prevalence of recorded cannabis exposure substantially lower than self-reported survey records.

Reduced motivation is often noted as a consequence of cannabis use. However, previous work has yielded mixed results and focused largely on adults. To address these limitations, this study examined longitudinal associations between cannabis use and self-reported motivation in a large adolescent sample.

Participants were 401 adolescents aged 14–17 at baseline who completed five bi-annual assessments. We assessed motivation at three timepoints using two self-report questionnaires: the Apathy Evaluation Scale and the Motivation and Engagement Scale (disengagement, persistence, planning, self-efficacy, and valuing school subscales). Controlling for relevant covariates, we used latent growth curve modeling to characterize patterns of cannabis use and motivation over time, examining bidirectional influences between these processes.

On average, adolescent cannabis use frequency increased significantly over time. The disengagement and planning facets of motivation also increased significantly over time, whereas other aspects of motivation remained stable. At baseline, greater cannabis use was associated with greater disengagement, lower planning, and lower valuing of school. Greater baseline cannabis use also predicted lesser increases in disengagement over time. After controlling for the effect of sex, age, depression, and use of alcohol and nicotine, only the baseline association between cannabis use and valuing school remained significant.

Our results do not support a prospective link between cannabis use and reduced motivation among adolescents. Although most observed associations were accounted for by covariates, greater cannabis use was cross-sectionally associated with lower perceived value of school, which may contribute to poorer educational and later life outcomes.

Although evidence from psychosis patients demonstrates the adverse effects of cannabis use (CU) at a young age and that the rate of CU is high in subgroups of young violent patients with psychotic disorders, little is known about the possible effect of the age of onset of CU on later violent behaviors (VB). So, we aimed to explore the impact of age at onset of CU on the risk of displaying VB in a cohort of early psychosis patients.

Data were collected prospectively over a 36-month period in the context of an early psychosis cohort study. A total of 265 patients, aged 18–35 years, were included in the study. Logistic regression was performed to assess the link between age of onset of substance use and VB.

Among the 265 patients, 72 had displayed VB and 193 had not. While violent patients began using cannabis on average at age 15.29 (0.45), nonviolent patients had started on average at age 16.97 (0.35) (p = 0.004). Early-onset CU (up to age 15) was a risk factor for VB (odds ratio = 4.47, confidence interval [CI]: 1.13–20.06) when the model was adjusted for age group, other types of substance use, being a user or a nonuser and various violence risk factors and covariates. History of violence and early CU (until 15) were the two main risk factors for VB.

Our results suggest that early-onset CU may play a role in the emergence of VB in early psychosis.

Why patients with psychosis use cannabis remains debated. The self-medication hypothesis has received some support but other evidence points towards an alleviation of dysphoria model. This study investigated the reasons for cannabis use in first-episode psychosis (FEP) and whether strength in their endorsement changed over time.

FEP inpatients and outpatients at the South London and Maudsley, Oxleas and Sussex NHS Trusts UK, who used cannabis, rated their motives at baseline (n = 69), 3 months (n = 29) and 12 months (n = 36). A random intercept model was used to test the change in strength of endorsement over the 12 months. Paired-sample t-tests assessed the differences in mean scores between the five subscales on the Reasons for Use Scale (enhancement, social motive, coping with unpleasant affect, conformity and acceptance and relief of positive symptoms and side effects), at each time-point.

Time had a significant effect on scores when controlling for reason; average scores on each subscale were higher at baseline than at 3 months and 12 months. At each time-point, patients endorsed ‘enhancement’ followed by ‘coping with unpleasant affect’ and ‘social motive’ more highly for their cannabis use than any other reason. ‘Conformity and acceptance’ followed closely. ‘Relief of positive symptoms and side effects’ was the least endorsed motive.

Patients endorsed their reasons for use at 3 months and 12 months less strongly than at baseline. Little support for the self-medication or alleviation of dysphoria models was found. Rather, patients rated ‘enhancement’ most highly for their cannabis use.

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.

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.

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.

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.

Young adults who are not in employment, education, or training (NEET) are at risk of long-term economic disadvantage and social exclusion. Knowledge about risk factors for being NEET largely comes from cross-sectional studies of vulnerable individuals. Using data collected over a 10-year period, we examined adolescent predictors of being NEET in young adulthood.

We used data on 1938 participants from the Victorian Adolescent Health Cohort Study, a community-based longitudinal study of adolescents in Victoria, Australia. Associations between common mental disorders, disruptive behaviour, cannabis use and drinking behaviour in adolescence, and NEET status at two waves of follow-up in young adulthood (mean ages of 20.7 and 24.1 years) were investigated using logistic regression, with generalised estimating equations used to account for the repeated outcome measure.

Overall, 8.5% of the participants were NEET at age 20.7 years and 8.2% at 24.1 years. After adjusting for potential confounders, we found evidence of increased risk of being NEET among frequent adolescent cannabis users [adjusted odds ratio (ORadj) = 1.74; 95% confidence interval (CI) 1.10–2.75] and those who reported repeated disruptive behaviours (ORadj = 1.71; 95% CI 1.15–2.55) or persistent common mental disorders in adolescence (ORadj = 1.60; 95% CI 1.07–2.40). Similar associations were present when participants with children were included in the same category as those in employment, education, or training.

Young people with an early onset of mental health and behavioural problems are at risk of failing to make the transition from school to employment. This finding reinforces the importance of integrated employment and mental health support programmes.

Substance use may increase the risk of non-adherence to antipsychotics, resulting in negative outcomes in patients with psychosis.

We aimed to quantitatively summarize evidence regarding the effect of cannabis use, the most commonly used illicit drug amongst those with psychosis, on adherence to antipsychotic medication. Studies were identified through a systematic database search. Adopting random-effects models, pooled odds ratios (OR) for risk of non-adherence to antipsychotic medications were calculated comparing: cannabis-users at baseline v. non-users at baseline; non users v. continued cannabis users at follow-up; non-users v. former users at follow-up; former users v. current users.

Fifteen observational studies (n = 3678) were included. Increased risk of non-adherence was observed for cannabis users compared to non-users (OR 2.46, n = 3055). At follow-up, increased risk of non-adherence was observed for current users compared to non-users (OR 5.79, n = 175) and former users (OR 5.5, n = 192), while there was no difference between former users and non-users (OR 1.12, n = 187).

Cannabis use increases the risk of non-adherence and quitting cannabis use may help adherence to antipsychotics. Thus, cannabis use may represent a potential target for intervention to improve medication adherence in those with psychosis.