Psychological Medicine
January 1, 2025
Sunjeev K. Kamboj, Matthew Peniket, Jessica Norman et al.
Transcutaneous vagus nerve stimulation (tVNS) combined with a brief self-compassion mental imagery training (SC-MIT) produced a larger acute increase in state self-compassion and mindfulness than either intervention alone in healthy adults. Over eight daily sessions, tVNS plus SC-MIT showed accumulating effects on mindfulness but not self-compassion. Self-criticism and attentional bias toward compassionate faces were influenced only by the type of imagery training, not by stimulation. Heart rate variability was unaffected by any condition. The findings suggest tVNS may enhance meditation-based psychotherapies, while oculomotor metrics appear sensitive to self-compassion training.
Psychological Medicine
July 13, 2026
Thorsten Barnhofer, Barnaby D. Dunn, Clara Strauss et al.
Mindfulness-based cognitive therapy (MBCT) plus treatment as usual leads to greater symptom improvement than treatment as usual alone in adults with difficult-to-treat depression who have not remitted after high-intensity psychological therapy. The therapy works partly by increasing decentering—the ability to observe thoughts and feelings as temporary mental events—and this mechanism remains effective even when depressive symptoms are severe. Higher baseline depression severity does not limit the acquisition of decentering skills or the overall treatment effect; instead, decentering is more strongly linked to symptom reduction in those with more severe depression. These findings support using MBCT across a broad range of symptom severity.
Psychological Medicine
January 1, 2024
Simon Kapler, Laura Adery, Gil D Hoftman et al.
Cannabis use is linked to increased rates of psychotic disorders and worsening of symptoms in people with psychosis spectrum disorders, including those at Clinical High Risk for Psychosis (CHR-P). While causality remains uncertain, cannabis may be a modifiable risk factor for conversion to psychotic disorder in CHR-P individuals. Current evidence supports a harm reduction approach rather than abstinence alone: reducing frequency of use, choosing lower delta-9-tetrahydrocannabinol content or cannabidiol-only products, avoiding edibles with inconsistent potency, improving patient-provider communication about cannabis use and psychotic-like experiences, and using a collaborative, individualized therapeutic approach. Whether these interventions lower conversion risk is unknown.
Psychological Medicine
May 4, 2023
G. Trotta, Victoria Rodriguez, D. Quattrone et al.
Childhood adversity and cannabis use are both known risk factors for psychosis. This study examined whether cannabis use might explain the link between childhood adversity and psychotic disorders. Data from 881 first-episode psychosis patients and 1231 controls from the EU-GEI study showed that household discord was associated with psychosis partly through cannabis use. Lifetime cannabis use mediated 17% of the association, cannabis potency mediated 14%, and frequency of use mediated 29%. Similar results appeared for early exposure to household discord. The findings suggest that harmful cannabis use patterns partially explain how household discord leads to psychosis, and children exposed to challenging home environments could benefit from interventions to prevent cannabis misuse.
Psychological Medicine
May 1, 2023
David Van den Berg, Eva Tolmeijer, Alyssa Jongeneel et al.
In people with psychosis who hear voices after experiencing trauma, trauma often shapes the content and emotional impact of those voices. Among 73 participants, independent links between trauma and voices—such as similar victimization types, emotional responses, or negative self-beliefs—were reported by 51-58% of participants and 8-41% of researchers. Dependent links, where the voice directly mirrored the trauma in content, identity, or relational dynamics, were found in 80% of participant reports and 66% of researcher ratings, with relational links being most common. Negative self-beliefs from trauma strongly predicted similar beliefs in voices. Trauma appears to be a powerful force shaping voice-hearing, suggesting that trauma-induced mechanisms may be important targets for intervention.
Psychological Medicine
April 1, 2023
Laurent Elkrief, Bochao Lin, Mattia Marchi et al.
Cannabis use at age 16 is associated with psychotic-like experiences (PLEs) even after accounting for genetic risk for schizophrenia, according to an analysis of 1740 European adolescents from the IMAGEN cohort and replicated in 1223 individuals from a Dutch cohort. Polygenic risk scores for schizophrenia predicted both cannabis use and PLEs, and cannabis use remained a significant predictor of PLEs in models including genetic risk. However, no evidence was found that genetic risk mediates or moderates the cannabis–psychosis link. The findings suggest cannabis use is a risk factor for PLEs independent of genetic vulnerability to schizophrenia.
Psychological Medicine
December 1, 2022
Fabiana Corsi-Zuelli, Leonardo Marques, Daiane Leite Da Roza et al.
Cannabis consumption is not associated with increased inflammation in first-episode psychosis patients or controls, indicating that inflammation does not mediate the cannabis-psychosis link. However, daily cannabis use and onset of use before age 17 interact with a composite measure of systemic inflammation to raise the odds of psychosis beyond the individual effects of either factor alone, and this association appears only among individuals with medium-to-high inflammatory scores. The authors propose that immune dysregulation may modify the cannabis-psychosis relationship, consistent with a two-hit hypothesis, and that immune dysregulation could be part of psychosis pathophysiology independent of cannabis use or other confounders.
Psychological Medicine
January 1, 2022
Wayne Hall
The abandonment of psychedelic drug research in the 1960s and 1970s was not solely caused by Richard Nixon's 'War on Drugs' but resulted from multiple converging factors. Tighter regulation of pharmaceutical research after the Thalidomide disaster in 1963, the failure of controlled clinical trials in the 1970s to match earlier positive claims, Sandoz ceasing to supply psychedelic drugs for research after 1965, and the prohibition of nonmedical use in 1970 all contributed. The pharmaceutical industry also showed little interest in funding trials.
Psychological Medicine
July 1, 2021
Annemarie C J Köhne, Jim van Os
Precision psychiatry promises to improve psychiatric practice by grounding diagnosis and treatment in biological markers, but a conceptual analysis of its foundations reveals they are obsolete and flawed. Mental suffering cannot be reduced to biological essences, because biological processes alone cannot capture qualia, meaning, or abnormality without context. Despite its intentions, precision psychiatry does not offer a sufficiently promising alternative to current phenotype-based classification systems.
Psychological Medicine
December 16, 2019
C. Hjorthøj, Maria Larsen, M. Starzer et al.
From 2006 to 2016, the incidence rate of cannabis-induced psychosis in Denmark rose from 2.8 to 6.1 per 100,000 person years. A corresponding increase occurred in dual diagnoses of schizophrenia with cannabis use disorder, while alcohol-induced psychosis decreased. Other substance-induced psychoses showed no clear trend. The rise in cannabis-induced psychosis parallels increases in both cannabis use and the THC content of cannabis, and changes in diagnostic practice do not appear to account for the increase.
Psychological Medicine
October 16, 2019
D. D’souza, S. Ganesh, J. Cortes-Briones et al.
Heavy, chronic cannabis use that begins early and is not accompanied by other drugs is associated with more psychosis-relevant symptoms and poorer cognitive performance. Users averaged over 30,000 lifetime cannabis exposures and scored higher on the Schizotypal Personality Questionnaire (mean 24 vs. 13) and lower on a composite cognitive test (mean -0.23 vs. +0.28) compared to matched non-user controls. Moderate to large deficits appeared in attention, psychomotor speed, working memory, cognitive flexibility, visuo-spatial processing, and verbal memory. A subsample of users also showed worse outcomes than their non-using siblings.
Psychological Medicine
July 19, 2019
J. Montero-Marín, J. García-Campayo, M. Pérez-Yus et al.
Meditation techniques that regulate attention or construct personal values are slightly more effective than relaxation therapy for reducing anxiety. A meta-analysis of 14 randomized controlled trials with 862 participants suffering from anxiety disorders or high trait anxiety found a small effect favoring meditation (Hedges' g = −0.23). The number needed to treat was 7.74. Heterogeneity among studies was low, and there was no evidence of publication bias, though few studies were of high quality and researcher allegiance may have influenced results. Meditation may remain more effective at 12-month follow-up, but more research is needed across the full range of meditation practices and anxiety disorders.
Psychological Medicine
November 1, 2011
J E Houston, J Murphy, M Shevlin et al.
Cannabis consumption alone did not predict psychosis diagnosis after accounting for childhood sexual abuse. Using data from the Adult Psychiatric Morbidity Survey 2007 (n=7403), the analysis showed that individuals who experienced non-consensual sex in childhood were over six times more likely to have a psychosis diagnosis. Those with both a history of non-consensual sexual experience and cannabis consumption were over seven times more likely to have been diagnosed with psychosis, though this interaction emerged in a non-significant analytical step. The authors argue that childhood trauma may advance gene-environment conceptualizations of the cannabis-psychosis link and that future studies should adjust for childhood trauma.
Psychological Medicine
August 1, 2010
S C Linden, M Harris, C Whitaker et al.
During the Welsh religious revival of 1904-1905, admissions to the North Wales Hospital for brief polymorphic psychoses (BPP) increased significantly, while first admissions for other mental disorders did not change. Most BPP admissions were linked to a revival meeting and did not result in further admissions. Intensive religious experience can lead to transient psychotic episodes, and BPP triggered by life events rarely lead to chronic mental illness, supporting the concept of reactive psychosis.
Psychological Medicine
July 1, 2007
Louisa Degenhardt, Chris Tennant, Stuart Gilmour et al.
Over 10 months, 101 patients with schizophrenia and related disorders were assessed monthly for cannabis use, medication compliance, and symptoms of psychosis and depression. Cannabis use predicted a small but statistically significant increase in psychotic symptoms, but not depressive symptoms, after controlling for other variables. Symptoms of depression and psychosis did not predict cannabis use. Continued cannabis use by persons with schizophrenia predicts a small increase in psychotic symptom severity, but not vice versa.
Psychological Medicine
April 1, 2007
Audrey Cougnard, Machteld Marcelis, Inez Myin-Germeys et al.
Psychotic experiences (like mild hallucinations or delusions) are common and often temporary in the general population. This study tested whether they become abnormally persistent when combined with environmental factors such as cannabis use, childhood trauma, and urban living. Using two large Dutch and German population samples, the authors found that persistence rates were low overall (26% and 31%) but increased progressively with more environmental exposures. Among those exposed to both environmental risks and baseline psychotic experiences, 21%-83% (Dutch sample) and 29%-51% (German sample) had persistent symptoms due to the synergistic interaction of these factors. The authors argue that environmental risks combine additively and synergistically with non-clinical psychotic experiences to drive persistence and eventual need for care.
Psychological Medicine
October 1, 2005
Mauricio Sierra, Dawn Baker, Nicholas Medford et al.
Depersonalization symptoms cluster into four distinct but related domains rather than forming a single syndrome. An analysis of responses to the Cambridge Depersonalization Scale from 138 patients diagnosed with depersonalization disorder identified four factors that together account for 73.3% of the variance: anomalous body experience, emotional numbing, anomalous subjective recall, and alienation from surroundings. This suggests that depersonalization is not a unitary condition but comprises separable psychopathological dimensions.
Psychological Medicine
May 1, 1980
Michael A. West
This review describes previous research on meditation and EEG, discussing findings on EEG patterns during meditation and comparing meditation with other altered states. Based on existing EEG evidence, there is some reason to differentiate meditation from drowsing. Research on alpha-blocking and habituation of the blocking response during meditation is reviewed, along with effects of meditation on EEG patterns outside of meditation. The authors conclude that more precisely formulated research is needed.
Psychological Medicine
May 1, 1978
M L Gentil, M Lader
Anxiety levels influence both how dreams are reported and their content. In a comparison of twenty female anxious neurotic patients with twenty-five normal female volunteers, aggression directed toward the dreamer appeared more often in the anxious patients. Significant links between dream content and daytime attitudes were found across all groups, supporting the continuity hypothesis of dream function.