Cannabis use and familial vulnerability to psychosis have been associated with social cognition deficits. This study examined the potential relationship between cannabis use and cognitive biases underlying social cognition and functioning in patients with first episode psychosis (FEP), their siblings, and controls.

We analyzed a sample of 543 participants with FEP, 203 siblings, and 1168 controls from the EU-GEI study using a correlational design. We used logistic regression analyses to examine the influence of clinical group, lifetime cannabis use frequency, and potency of cannabis use on cognitive biases, accounting for demographic and cognitive variables.

FEP patients showed increased odds of facial recognition processing (FRP) deficits (OR = 1.642, CI 1.123–2.402) relative to controls but not of speech illusions (SI) or jumping to conclusions (JTC) bias, with no statistically significant differences relative to siblings. Daily and occasional lifetime cannabis use were associated with decreased odds of SI (OR = 0.605, CI 0.368–0.997 and OR = 0.646, CI 0.457–0.913 respectively) and JTC bias (OR = 0.625, CI 0.422–0.925 and OR = 0.602, CI 0.460–0.787 respectively) compared with lifetime abstinence, but not with FRP deficits, in the whole sample. Within the cannabis user group, low-potency cannabis use was associated with increased odds of SI (OR = 1.829, CI 1.297–2.578, FRP deficits (OR = 1.393, CI 1.031–1.882, and JTC (OR = 1.661, CI 1.271–2.171) relative to high-potency cannabis use, with comparable effects in the three clinical groups.

Our findings suggest increased odds of cognitive biases in FEP patients who have never used cannabis and in low-potency users. Future studies should elucidate this association and its potential implications.

Tobacco is a highly prevalent substance of abuse in patients with psychosis. Previous studies have reported an association between tobacco use and schizophrenia. The aim of this study was to analyze the relationship between tobacco use and first-episode psychosis (FEP), age at onset of psychosis, and specific diagnosis of psychosis.

The sample consisted of 1105 FEP patients and 1355 controls from the European Network of National Schizophrenia Networks Studying Gene–Environment Interactions (EU-GEI) study. We assessed substance use with the Tobacco and Alcohol Questionnaire and performed a series of regression analyses using case-control status, age of onset of psychosis, and diagnosis as outcomes and tobacco use and frequency of tobacco use as predictors. Analyses were adjusted for sociodemographic characteristics, alcohol, and cannabis use.

After controlling for cannabis use, FEP patients were 2.6 times more likely to use tobacco [p ⩽ 0.001; adjusted odds ratio (AOR) 2.6; 95% confidence interval (CI) [2.1–3.2]] and 1.7 times more likely to smoke 20 or more cigarettes a day (p = 0.003; AOR 1.7; 95% CI [1.2–2.4]) than controls. Tobacco use was associated with an earlier age at psychosis onset (β = −2.3; p ⩽ 0.001; 95% CI [−3.7 to −0.9]) and was 1.3 times more frequent in FEP patients with a diagnosis of schizophrenia than in other diagnoses of psychosis (AOR 1.3; 95% CI [1.0–1.8]); however, these results were no longer significant after controlling for cannabis use.

Tobacco and heavy-tobacco use are associated with increased odds of FEP. These findings further support the relevance of tobacco prevention in young populations.

A growing body of literature suggests that people affected by psychotic disorders are more likely to be unemployed, tend to live alone, have a poor social network, and are not able to establish long-term relationships (Morgan et al., 2008).

To investigate social disadvantage in a sample of first-episode of psychosis patients and geographically matched controls.

The study sample consists of 52 healthy controls and 37 FEP who were assessed using the MRC Sociodemographic Schedules.

Preliminary results suggest that, consistently with the literature, cases are more exposed than controls to social disadvantage. They tend to reach a lower education degree (OR 6.66; CI 95%, 1.67–26.50, p 0.005) and to have an underpaid job 5 years before the onset (OR 2.84; CI 95%, 1.08–7.45, p 0.03). Furthermore, cases are more likely to live longer with their parents rather than independently (OR 3.33; CI 95%, 1.25–8.86, p 0.01) and are more exposed to house overcrowding (OR 3.92; CI 95%, 1.03–14.93, p 0.05). It was also found that an higher percentage of cases have never been in a stable relationship in the previous 5 years (OR 2.61; CI 95%, 1.08–6.27, p 0.03).

In line with the previous literature, we found that lower educational and occupational status and poor relationship status are associated to risk for psychosis. However, in contrast with North European cases, Italian FEP are more likely to live with their family rather than alone and, therefore, to be exposed to house overcrowding.

A large body of literature has demonstrated that people affected by psychotic disorders show deficits in working memory, in Emotion Recognition (ER) and in data-gathering to reach a decision (Jumping To Conclusions – JTC).

To investigate a possible correlation between working memory, JTC and ER in FEP.

41 patients and 89 healthy controls completed assessments of working memory using WAIS shortened version, JTC using the 60:40 Beads Task and ER using Degraded Facial Affect Recognition Task.

According to the literature, cases had poorer performance in working memory tasks (Digit Span: μ7,72 [ds=2,98] vs μ10,14 [ds=3,10], U=865,00, p=0,00; Digit Symbol: μ5,36 [ds=2,43] vs μ10,05 [ds=3,10], U=455,50, p=0,00; Arithmetic: μ5,46 [ds=2,76] vs μ8,74 [ds=3,24], U=865,50, p=0,00; Block Design: μ4,82 [ds=2,72] vs μ7,60 [ds=3,18], U=912,00, p=0,00), in Beads Task (81,6% vs 51,1%, χ2=10,27, p=0,001, μ2,53 [ds=3,57] vs μ4,23 [ds=4,77], U=1171,00, p=0,006) and in DFAR (total errors: μ21,62 [ds=7,43] vs μ16,58 [ds=8,69], U=554,50, p=0,002). Furthermore working memory tasks in cases group correlated significantly with JTC (Digit Span: r_rho=0,276, p=0,003; Digit Symbol: r_rho=0,275, p=0,002; Arithmetic: r_rho=0,265, p=0,003; Block Design: r_rho=0,292, p=0,001), but only Digit Span with ER (r_rho=-0,239; p=0,021). In addition, we found that JTC and ER were significantly associated (r_rho=-0,281; p=0,004).

Data show that working memory impairments, JTC style and dysfunctions in the facial emotions recognition are phenomena strongly correlated in the group of patients. Preliminary results suggest the importance of early rehabilitation as the impairments detected may lead to difficulties in social and relational adaptation in psychotic patients.

A number of authors have hypothesized that psychotic patients who consume cannabis constitute a differentiated subgroup of patients that have better cognitive and social skills, necessary to engage in illegal drug consumption, than non-using patients.

Given that the prevalence, and patterns, of cannabis use are culturally driven, we wanted to study first-episode psychosis (FEP) cannabis-using and non-using patients coming from different European countries as part of the EUGEI-STUDY.

We tested the hypothesis of better premorbid social adjustment in cannabis-using FEP patients, by comparing them to FEP non cannabis users and to their respective healthy controls.

A total of 1745 people (746 cases; 999 controls) completed the assessment for premorbid adjustment [Premorbid Adjustment Scale (PAS)] and cannabis use (CEQ-Revised). We first extracted the Premorbid Social Adjustment Factor (PSA) from PAS and then performedlinear mixed models with PSA as dependent variable and cannabis lifetime (Yes/No) and subject status (Cases/Controls) as independent variables. We then considered “Country” as random intercept.

Across all countries, PSA scores were better in patients who had smoked cannabis in their lifetime than patients who had not (P = 0.009). The difference in PSA score between cannabis users and non-users was significantly greater in cases than controls (P = 0.038). The relationship between PSA, cannabis lifetime (Yes/No) and subject status among nations (random intercept) is shown on Fig. 1.

Cannabis-using psychotic patients show better premorbid social adjustment than non-using patients, across 5 European countries.

The authors have not supplied their declaration of competing interest.

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.