Abstract Background Epidemiological data have consistently shown an association between heavy cannabis use and increased risk of psychotic disorders. Nevertheless, not all cannabis users develop the illness. Evidence from other substance of abuse such as Alcohol suggest how genetic differences in enzymes involved in its metabolism influence individual response to the drug. No studies to data...
Abstract Background Adolescent cannabis use is associated with an increased risk of psychosis, yet the underlying molecular mechanisms remain poorly understood. Emerging evidence also pointed to genetic liability shaping individual risk of cannabis-induced psychosis. The neuregulin–ErbB4 signalling pathway, implicated in schizophrenia-related neurodevelopment, may modulate individual...
BACKGROUND: Cannabis use is common in people with psychosis and is associated with poor outcomes. AIMS: To assess insight into cannabis use disorder, perceptions about how cannabis use influences mental health and the desire to change cannabis use among people with psychotic disorders. METHOD: Adults with a psychotic disorder and comorbid cannabis use disorder were asked about the impact of...
Background Cannabis use is associated with increased risk of psychotic disorders, but the underlying biological mechanisms remain unclear. We used genetic data to investigate the molecular pathways contributing to the association between cannabis use disorder (CUD) and psychosis. Methods We conducted a cross-disorder meta-analysis of genome-wide association studies (GWASs) on schizophrenia and...
Recreational use of psychotogenic drugs has become more common in the last 30 years with consequent increase in drug-induced psychosis; 25-50% of such psychoses progress to schizophrenia within 5 years. Most cases result from abuse of methamphetamine or cannabis. The spread of methamphetamine psychosis has occurred without any liberalisation of laws; it is highly addictive and easy to make in...
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...
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...
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...
The fact that not all cannabis users will develop psychosis suggests that cannabis may exert its causal role only in pre-disposed individuals. However, since the number of people who use cannabis worldwide is so high, those who will eventually develop psychosis, whilst still a minority, represent a large number. The evidence indicates that different patterns of cannabis use have a different...
Abstract Background 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. Methods Data were...
Abstract Background 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. Methods 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...
Psychological MedicineDecember 1, 2022Fabiana Corsi-Zuelli, Leonardo Marques, Daiane Leite Da Roza et al.
Cannabis consumption is a modifiable risk factor associated with psychosis, but not all cannabis users develop psychosis. Animal studies suggest that an antecedent active immune system interacts with subsequent cannabis exposure and moderates the cannabis-psychosis association, supporting the two-hit hypothesis. The clinical investigations are few, and it is unclear if the immune system is a...
Diagnostic categories do not completely reflect the heterogeneous expression of psychosis. Using data from the EU-GEI study, we evaluated the impact of schizophrenia polygenic risk score (SZ-PRS) and patterns of cannabis use on the transdiagnostic expression of psychosis. We analysed first-episode psychosis patients (FEP) and controls, generating transdiagnostic dimensions of psychotic symptoms...
Cannabis is one of the most widely used recreational drugs among people with clinical psychosis, after nicotine and alcohol. There has been a debate in psychiatry about whether or not we can infer a cause-and-effect relationship between the use of cannabis and psychotic disorders. In this editorial, we first present and critically discuss the evidence to date of the association between heavy...
Epidemiological and biological evidence support the association between heavy cannabis use and psychosis. However, it is unclear which cannabis users are susceptible to its psychotogenic effect. Therefore, understanding genetic factors contributing to this relationship might prove an important strategy to identify the mechanisms underlying cannabis-associated psychotic experiences. We aimed to...
Abstract Background 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. Method We analysed data from 901 FEP patients and 1235 controls recruited across six countries, as part of...
Psychotic patients with a lifetime history of cannabis use generally show better cognitive functioning than other psychotic patients. Some authors suggest that cannabis-using patients may have been less cognitively impaired and less socially withdrawn in their premorbid life. Using a dataset comprising 948 patients with first-episode psychosis (FEP) and 1313 population controls across 6...
Summary Background Cannabis use is associated with increased risk of later psychotic disorder but whether it affects incidence of the disorder remains unclear. We aimed to identify patterns of cannabis use with the strongest effect on odds of psychotic disorder across Europe and explore whether differences in such patterns contribute to variations in the incidence rates of psychotic disorder....
Abstract Objective The evidence is mixed on whether cannabis use is associated with a particular symptomatology in first episode psychosis (FEP) patients. The authors set out to investigate a) patterns of association between cannabis use and transdiagnostic symptom dimensions; b) whether the extent of use of cannabis contributes to the variation in clinical and subclinical symptom profiles....
Abstract Background Cannabis has been associated with higher risk to develop psychosis and worse long-term outcomes. Cannabis use in 2016 is estimated to be 11.3% in Chile in 2016 (SENDA 2016). As in many other countries, cannabis use has steadily increased during last 20 years, across all socioeconomic groups, but especially in men and in the group aged 12 to 25 years old. At the same time,...
Abstract Background Cannabis use remains the most widely used recreational drug worldwide. Following from several USA states legalisation policies, European countries are reconsidering their cannabis laws. While a significant amount of Epidemiological evidence has reported that cannabis use increases the risk of psychosis it is still unclear: 1) what underpins individual differences in...
Abstract Background Patients presenting to psychiatric services with their first episode of psychosis (FEP) report higher rates of previous cannabis use than the general population (Donoghue et al., 2011; Myles, Myles and Large, 2016). Evidence suggested that patients suffering from psychosis with a history of cannabis use have an earlier age of onset of psychosis (AOP) than those who never...
In 2005 and 2008, studies reported that cannabis in England had become dominated by the sinsemilla (unseeded female) form. The average potency (Δ9 -tetrahydrocannabinol [THC] content) of this material had doubled over the previous decade. Cannabis resin then circulating contained approximately equal ratios of THC and cannabidiol (CBD), whereas sinsemilla was almost devoid of CBD. Despite raised...
Background Cannabis use following the onset of first-episode psychosis has been linked to both increased risk of relapse and non-adherence with antipsychotic medication. Whether poor outcome associated with cannabis use is mediated through an adverse effect of cannabis on medication adherence is unclear. Methods In a prospective analysis of data acquired from four different adult inpatient and...
BACKGROUND Although cannabis use after a first episode of psychosis has been associated with relapse, little is known about the determinants of this most preventable risk factor for relapse of psychosis. Here we aimed to study whether the effects on outcome vary depending on the type of cannabis consumed and usage pattern. METHODS In this observational study, we prospectively recruited and...