Psilocybin use has increased in the US alongside promising therapeutic potential for depression, raising concerns that individuals may forgo conventional mental health treatment for unsupervised psilocybin use. However, no nationally representative studies have examined whether psilocybin use is associated with differential treatment utilization or perceived unmet need for mental health care...
Psychological MedicineSeptember 9, 2026Chantal Miller-Silva, B. Illingworth, Kirsten Martey et al.
Abstract Background The influential predictive processing theory of psychosis posits that symptoms arise from an imbalanced weighting of predictions (priors) and sensory evidence, yet studies present conflicting results. This is particularly problematic as findings from single tasks with modest sample sizes are frequently used to advance a theory for a generalized altered reliance on priors in...
Psychiatric disorders are complex conditions involving multifactorial, nonlinear causal dynamics, which make effective treatment challenging. To address this complexity, a framework is proposed that distinguishes between types of causality: permissive causality, which pertains to factors affecting the likelihood of an outcome occurring, and instructive causality, which refers to factors shaping...
Mindfulness-based cognitive therapy (MBCT) was developed for relapse prevention in people with remitted depression but is increasingly used for those with difficult-to-treat depression (DTD). A key question regarding this broader application is whether ongoing depressive symptoms constrain therapeutic responsiveness or disrupt MBCT's proposed mechanism, decentering. We explored whether baseline...
Intravenous (IV) low-dose ketamine has emerged as a promising treatment for patients with treatment-resistant depression (TRD). However, its impact on cognitive functioning remains unclear. This systematic review examines the cognitive and executive effects of IV ketamine in TRD, focusing on their relationship to depressive and suicidal outcomes. A systematic search of Cochrane, MEDLINE,...
Abstract Background In recent decades, the potency of cannabis resin increased globally, raising concerns, as higher potency has been associated with increased risk of psychiatric harms at the individual level. The aim here was to examine whether changes over time in the potency of seized cannabis resin samples were associated with psychiatric harms at the population level. Methods Data on...
This systematic review and meta-analyses provide the first synthesis of the literature on trait mindfulness and psychotic-like experiences (PLEs). Theoretical models suggest a protective function of mindfulness and it is important to understand any potential role of mindfulness in the prevention and treatment of PLEs. We examined the following: (1) What is the relationship between trait...
Auditory verbal hallucinations (AVH) in schizophrenia spectrum disorders (SSDs) may arise from misattributed inner speech. However, it is unclear if inner speech frequency and phenomenology differ in schizophrenia-spectrum voice-hearers compared with healthy individuals, and how different inner speech varieties relate to AVH and affect. Using experience sampling methodology (ESM), this study...
Abstract Background Nonsuicidal self-injury (NSSI) in adolescents with depressive disorder is characterized by recurrent impulsivity and is a predictor of future suicidal behavior, necessitating effective and feasible interventions. Mindfulness-based cognitive therapy for adolescents (MBCT-A), a first-line treatment for depression, was evaluated in this trial for its efficacy in reducing NSSI...
BACKGROUND: While clinical research on psychedelics often reports mild and transient side effects, broader survey studies indicate that a subset of users experiences lasting adverse mental health effects. This study investigated whether some of these meet diagnostic criteria for post-traumatic stress disorder (PTSD). METHODS: = 243) was conducted with individuals reporting distressing...
Abstract: Background: The use of cannabis in adolescence and early adulthood, critical phases for brain development, is linked to psychotic-like experiences (PLEs). The underlying mechanisms, however, remain unclear. This research examined the relationship between recreational cannabis use and PLEs, emphasizing the connectivity of the salience network (SN), which plays a role in salience...
Psychological MedicineAugust 26, 2025Lydia Johnson-Ferguson, Michelle Loher, Laura Bechtiger et al.2 citations
Cannabis use in young adulthood is common, yet few studies have explored how it predicts changes in psychopathology and functional well-being in community samples. We assessed these links using both self-reported frequency of cannabis use and hair THC concentrations. Data came from a community sample of young adults (N = 863) who reported cannabis use (weekly-to-daily use: n = 150) and provided...
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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...
Abstract Background The brain’s default mode network (DMN) plays a role in social cognition, with altered DMN function being associated with social impairments across various neuropsychiatric disorders. However, the genetic basis linking sociability with DMN function remains underexplored. This study aimed to elucidate the shared genetics and causal relationship between sociability and...
BACKGROUND: Findings from contemporary clinical trials suggest that psychedelics are generally safe and may be effective in the treatment of various psychiatric disorders. However, less is known about the risks associated with psychedelic use outside of medically supervised contexts, particularly in populations that are typically excluded from participation in clinical trials. METHODS:...
Abstract Based on promising preliminary results from clinical trials, it seems likely that psychedelic substances (classic serotonergic psychedelics, such as psilocybin, and entactogens, such as MDMA) will be introduced into psychiatry as psychedelic-assisted therapy. This also raises a range of ethical questions that urgently need to be addressed before widespread roll-out in society. This...
Abstract Background Physiological signals conveyed by the vagus nerve may generate quiescent psychological states conducive to contemplative practices. This suggests that vagal neurostimulation could interact with contemplative psychotherapies (e.g. mindfulness and compassion-based interventions) to augment their efficacy. Methods In a fully factorial experimental trial, healthy adults ( n =...
Psychedelic drugs are a focus of interest in the treatment of depression and other disorders but there are longstanding concerns about possible adverse psychiatric consequences. Because the relevant literature is largely informal, the seriousness of these risks is difficult to evaluate. Searches were made for case reports of schizophrenia-spectrum, affective or other psychiatric disorders after...
Background 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. Methods We analyzed a sample of 543 participants with FEP, 203...
Abstract Background Access to psychedelic drugs is liberalizing, yet responses are highly unpredictable. It is therefore imperative that we improve our ability to predict the nature of the acute psychedelic experience to improve safety and optimize potential therapeutic outcomes. This study sought to validate the ‘Imperial Psychedelic Predictor Scale’ (IPPS), a short, widely applicable,...
Background: Shame is experienced as a threat to social self, and so activates threat-protective responses. There is evidence that shame has trauma-like characteristics, suggesting it can be understood within the same conceptual framework as trauma and dissociation. Evidence for causal links among trauma, dissociation, and psychosis thus warrant the investigation of how shame may influence...
To investigate the association between pre-trial expectancy, suggestibility, and response to treatment in a trial of escitalopram and investigational drug, COMP360, psilocybin, in the treatment of major depressive disorder (ClinicalTrials.gov registration: NCT03429075). We used data (n = 55) from our recent double-blind, parallel-group, randomized head-to-head comparison trial of escitalopram...
BACKGROUND We examined whether cannabis use contributes to the increased risk of psychotic disorder for non-western minorities in Europe. METHODS We used data from the EU-GEI study (collected at sites in Spain, Italy, France, the United Kingdom, and the Netherlands) on 825 first-episode patients and 1026 controls. We estimated the odds ratio (OR) of psychotic disorder for several groups of...
Previous research has proposed that there may be potential synergies between psychedelic and meditation interventions, but there are still knowledge gaps that merit further investigation. Using a longitudinal observational research design with samples representative of the US and UK adult population with regard to sex, age, and ethnicity (N = 9732), we investigated potential associations...