Childhood trauma is a well-established risk factor for psychosis, paranoia, and substance use, with cannabis being a modifiable environmental factor that exacerbates these vulnerabilities. This study examines the interplay between childhood trauma, cannabis use, and paranoia using standard tetrahydrocannabinol (THC) units as a comprehensive measure of cannabis exposure.

Data were derived from the Cannabis&Me study, an observational, cross-sectional, online survey of 4,736 participants. Childhood trauma was assessed using a modified Childhood Trauma Screen Questionnaire, while paranoia was measured via the Green Paranoid Thoughts Scale. Cannabis use was quantified using weekly standard THC units. Structural equation modeling (SEM) was employed to evaluate direct and indirect pathways between trauma, cannabis use, and paranoia.

Childhood trauma was strongly associated with paranoia, particularly emotional, and physical abuse (β = 16.10, q < 0.001; β = 16.40, q < 0.001). Cannabis use significantly predicted paranoia (β = 0.009, q < 0.001). Interactions emerged between standard THC units and both emotional abuse (β = 0.011, q < 0.001) and household discord (β = 0.011, q < 0.001). SEM revealed a small but significant indirect effect of trauma on paranoia via cannabis use (β = 0.004, p = 0.017).

These findings highlight childhood trauma as a primary driver of paranoia, with cannabis use amplifying its effects. While trauma had a strong direct impact, cannabis played a significant mediating role. Integrating standard THC units into psychiatric research and clinical assessments may enhance risk detection and refine intervention strategies, particularly for childhood trauma-exposed individuals.

Cannabis use severely affects the outcome of people with psychotic disorders, yet there is a lack of treatments. To address this, in 2019 the National Health Service (NHS) Cannabis Clinic for Psychosis (CCP) was developed to support adults suffering from psychosis to reduce and/or stop their cannabis use.

Examine outcome data from the first 46 individuals to complete the CCP's intervention.

The sample (N = 46) consisted of adults (aged ≥ 18) with psychosis under the care of the South London and Maudsley NHS Foundation Trust, referred to the CCP between January 2020 and February 2023, who completed their intervention by September 2023. Clinical and functional measures were collected before (T0) and after (T1) the CCP intervention (one-to-one sessions and peer group attendance). Primary outcomes were changes in the Cannabis Use Disorders Identification Test-Revised (CUDIT-R) score and pattern of cannabis use. Secondary outcomes included T0–T1 changes in measures of delusions, paranoia, depression, anxiety and functioning.

A reduction in the mean CUDIT-R score was observed between T0 (mean difference = 17.10, 95% CI = 15.54–18.67) and T1, with 73.91% of participants achieving abstinence and 26.09% reducing the frequency and potency of their use. Significant improvements in all clinical and functional outcomes were observed, with 90.70% being in work or education at T1 compared with 8.70% at T0. The variance in CUDIT-R scores explained between 34 and 64% of the variance in our secondary measures.

The CCP intervention is a feasible strategy to support cannabis use cessation/reduction and improve clinical and functional outcomes of people with psychotic disorders.

The association between cannabis and psychosis is established, but the role of underlying genetics is unclear. We used data from the EU-GEI case-control study and UK Biobank to examine the independent and combined effect of heavy cannabis use and schizophrenia polygenic risk score (PRS) on risk for psychosis.

Genome-wide association study summary statistics from the Psychiatric Genomics Consortium and the Genomic Psychiatry Cohort were used to calculate schizophrenia and cannabis use disorder (CUD) PRS for 1098 participants from the EU-GEI study and 143600 from the UK Biobank. Both datasets had information on cannabis use.

In both samples, schizophrenia PRS and cannabis use independently increased risk of psychosis. Schizophrenia PRS was not associated with patterns of cannabis use in the EU-GEI cases or controls or UK Biobank cases. It was associated with lifetime and daily cannabis use among UK Biobank participants without psychosis, but the effect was substantially reduced when CUD PRS was included in the model. In the EU-GEI sample, regular users of high-potency cannabis had the highest odds of being a case independently of schizophrenia PRS (OR daily use high-potency cannabis adjusted for PRS = 5.09, 95% CI 3.08–8.43, p = 3.21 × 10−10). We found no evidence of interaction between schizophrenia PRS and patterns of cannabis use.

Regular use of high-potency cannabis remains a strong predictor of psychotic disorder independently of schizophrenia PRS, which does not seem to be associated with heavy cannabis use. These are important findings at a time of increasing use and potency of cannabis worldwide.

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 novel paediatric disease, multi-system inflammatory syndrome in children, has emerged during the 2019 coronavirus disease pandemic.

To describe the short-term evolution of cardiac complications and associated risk factors in patients with multi-system inflammatory syndrome in children.

Retrospective single-centre study of confirmed multi-system inflammatory syndrome in children treated from 29 March, 2020 to 1 September, 2020. Cardiac complications during the acute phase were defined as decreased systolic function, coronary artery abnormalities, pericardial effusion, or mitral and/or tricuspid valve regurgitation. Patients with or without cardiac complications were compared with chi-square, Fisher’s exact, and Wilcoxon rank sum.

Thirty-nine children with median (interquartile range) age 7.8 (3.6–12.7) years were included. Nineteen (49%) patients developed cardiac complications including systolic dysfunction (33%), valvular regurgitation (31%), coronary artery abnormalities (18%), and pericardial effusion (5%). At the time of the most recent follow-up, at a median (interquartile range) of 49 (26–61) days, cardiac complications resolved in 16/19 (84%) patients. Two patients had persistent mild systolic dysfunction and one patient had persistent coronary artery abnormality. Children with cardiac complications were more likely to have higher N-terminal B-type natriuretic peptide (p = 0.01), higher white blood cell count (p = 0.01), higher neutrophil count (p = 0.02), severe lymphopenia (p = 0.05), use of milrinone (p = 0.03), and intensive care requirement (p = 0.04).

Patients with multi-system inflammatory syndrome in children had a high rate of cardiac complications in the acute phase, with associated inflammatory markers. Although cardiac complications resolved in 84% of patients, further long-term studies are needed to assess if the cardiac abnormalities (transient or persistent) are associated with major cardiac events.

We examined parent- and adolescent-reported executive functioning (EF) behaviors following pediatric traumatic brain injury (TBI) in the context of Online Family Problem-Solving Therapy (OFPST) and moderators of change in EF behaviors.

In total, 274 families were randomized to OFPST or an internet resource comparison group. Parents and adolescents completed the Behavior Rating Inventory of Executive Function at four time points. Mixed models were used to examine EF behaviors, assessing the effects of visit, treatment group, rater, TBI severity, age, socioeconomic status, and family functioning.

Parents rated their adolescents’ EF as poorer (F(3,1156) = 220.15, p < .001; M = 58.11, SE = 0.73) than adolescents rated themselves (M = 51.81, SE = 0.73). Across raters, EF behaviors were poorer for adolescents whose parents had less education (F(3,1156) = 8.60, p = .003; M = 56.76, SE = 0.98) than for those with more education (M = 53.16, SE = 0.88). Age at baseline interacted with visit (F(3,1156) = 5.05, p = .002), such that families of older adolescents reported improvement in EF behaviors over time. Family functioning also interacted with visit (F(3, 1156) = 2.61, p = .049), indicating more improvement in EF behaviors over time in higher functioning families. There were no effects of treatment or TBI severity.

We identified a discrepancy between parent- and adolescent-reported EF, suggesting reduced awareness of deficits in adolescents with TBI. We also found that poorer family functioning and younger age were associated with poorer recovery after TBI, whereas adolescents of parents with less education were reported as having greater EF deficits across time points.