Cannabis psychosis, gender matters

Gender Differences in Dual Diagnoses Associated with Cannabis Use: A Review

Gender differences in psychiatric disorders and drug use are well known. Cannabis is the most widely used illegal drug among young people. In recent years, its use has been related to the development of psychiatric pathologies; however, few studies have incorporated the gender perspective as of yet. The present work analyses the literature to determine the existence of gender differences in the development of psychotic, depressive and anxious symptoms associated with cannabis use. First, we describe cannabis misuse and its consequences, paying special attention to adolescent subjects. Second, the main gender differences in psychiatric disorders, such as psychosis, depression, anxiety and cannabis use disorders, are enumerated. Subsequently, we discuss the studies that have evaluated gender differences in the association between cannabis use and the appearance of psychotic, depressive and anxious symptoms; moreover, we consider the possible explanations for the identified gender differences. In conclusion, the studies referred to in this review reveal the existence of gender differences in psychiatric symptoms associated with cannabis use, although the direction of such differences is not always clear. Future research is necessary to discern the causal relationship between cannabis use and the development of psychiatric symptoms, as well as the gender differences found.

Association between age of cannabis initiation and gray matter covariance networks in recent onset psychosis

Cannabis use during adolescence is associated with an increased risk of developing psychosis. According to a current hypothesis, this results from detrimental effects of early cannabis use on brain maturation during this vulnerable period. However, studies investigating the interaction between early cannabis use and brain structural alterations hitherto reported inconclusive findings. We investigated effects of age of cannabis initiation on psychosis using data from the multicentric Personalized Prognostic Tools for Early Psychosis Management (PRONIA) and the Cannabis Induced Psychosis (CIP) studies, yielding a total sample of 102 clinically-relevant cannabis users with recent onset psychosis. GM covariance underlies shared maturational processes. Therefore, we performed source-based morphometry analysis with spatial constraints on structural brain networks showing significant alterations in schizophrenia in a previous multisite study, thus testing associations of these networks with the age of cannabis initiation and with confounding factors. Earlier cannabis initiation was associated with more severe positive symptoms in our cohort. Greater gray matter volume (GMV) in the previously identified cerebellar schizophrenia-related network had a significant association with early cannabis use, independent of several possibly confounding factors. Moreover, GMV in the cerebellar network was associated with lower volume in another network previously associated with schizophrenia, comprising the insula, superior temporal, and inferior frontal gyrus. These findings are in line with previous investigations in healthy cannabis users, and suggest that early initiation of cannabis perturbs the developmental trajectory of certain structural brain networks in a manner imparting risk for psychosis later in life.

Risk Factors for Cannabis-Related Mental Health Harms in Older Adults: A Review

Objectives: This paper reviews research on the topic of cannabis use and mental health harms in older adults and illustrates potential contributing factors and special clinical considerations for working with this population. Known risk factors for cannabis-related mental disorders and mental health problems are outlined, first for the general population and then specifically for older adults. Methods: Studies were identified through online databases using a variety of search words. Articles were included in the review if they were peer-reviewed or published by a reputable national organization, published in English, and were pertinent to the topic of mental health harms of cannabis use. Results: Risk factors that emerged from the literature review aligned with the following categories: (1) patterns of use (i.e., potency of product, frequency of use), (2) personal characteristics (i.e., age, sex, social demographics), (3) psychosocial constructs (motivations, perceptions), and (4) morbidities (mental health, medication interactions). Conclusions: Frequent use was associated with increased risk for mental health consequences related to cannabis use. Certain motives for use (i.e., using to cope, using as a sleep aid) may increase susceptibility to cannabis-related harms, although more empirical work is required. Mental health conditions may predispose to cannabis-related harms through a variety of mechanisms, including increased vulnerability for cannabis-related psychiatric disorders, poorer prognosis for preexisting psychiatric disorders, and possibility of cannabis-medication interactions. Personal characteristics (younger age, being male, lower socioeconomic status) predict more frequent cannabis use, which may dispose to adverse outcomes. Clinical Implications: Predictors of cannabis-related harms hold relevance for public health messaging, as well as clinical interventions. Understanding how cannabis interacts with sociodemographic factors, mental health morbidities, and medications is crucial in providing accurate guidance to patients about their recreational cannabis use and in informing prescriber decisions about medicinal cannabis.

Cannabis and Psychosis: Are We any Closer to Understanding the Relationship?

PURPOSE OF REVIEW

This paper provides an update from the literature on understanding of the relationship between cannabis and schizophrenia. In particular, the paper focuses on the latest findings and remaining areas that require investigation.

RECENT FINDINGS

Three hypotheses have emerged as potential explanations for the association between cannabis and schizophrenia, namely cannabis can trigger schizophrenia, cannabis is used to mitigate symptoms of schizophrenia, and there are common factors which might account for the association. Biological and genetic factors dominate this field of research; this has been at the expense of exploring social and cultural contributory factors which influence cannabis and schizophrenia. The evidence for cannabis acting as a causal factor for schizophrenia has so far not been established. Research needs to extend beyond males drawn from western countries if we are to advance knowledge and understanding of the link between cannabis use and schizophrenia.

Effect of cannabis on glutamate signalling in the brain: A systematic review of human and animal evidence

Use of cannabis or delta-9-tetrahydrocannabinol (Δ9-THC), its main psychoactive ingredient, is associated with psychotic symptoms or disorder. However, the neurochemical mechanism that may underlie this psychotomimetic effect is poorly understood. Although dopaminergic dysfunction is generally recognized as the final common pathway in psychosis, evidence of the effects of Δ9-THC or cannabis use on dopaminergic measures in the brain is equivocal. In fact, it is thought that cannabis or Δ9-THC may not act on dopamine firing directly but indirectly by altering glutamate neurotransmission. Here we systematically review all studies examining acute and chronic effects of cannabis or Δ9-THC on glutamate signalling in both animals and man. Limited research carried out in humans tends to support the evidence that chronic cannabis use reduces levels of glutamate-derived metabolites in both cortical and subcortical brain areas. Research in animals tends to consistently suggest that Δ9-THC depresses glutamate synaptic transmission via CB1 receptor activation, affecting glutamate release, inhibiting receptors and transporters function, reducing enzyme activity, and disrupting glutamate synaptic plasticity after prolonged exposure.