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...
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...
Evidence for case–control studies suggests that cannabis use is a risk factor for the development of psychosis. However, there have been limited prospective studies and the direction of this association remains controversial. The primary aim of the present study was to examine the association between cannabis use and the incidence of psychotic disorders in people at clinical high risk of...
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...
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....
Cannabis use disorders are frequently comorbid in patients with a psychotic disorder and are associated with worse outcomes. To date there are no proven effective strategies to achieve cannabis abstinence in this population. An alternative for abstinence might be harm reduction, i.e. replacing the use of street cannabis with high tetrahydrocannabinol and low cannabidiol levels by medicinal...
Background: Schizophrenia is characterized by positive and negative symptoms, but recently anomalous self-experiences, e.g. exaggerated self-consciousness (hyperreflectivity), receive more attention as an important symptom domain in schizophrenia patients. The semi-structured interview, the Examination of Anomalous Self-Experience (EASE) [Psychopathology 2005;38:236-258], examines experiences...
Recently, a mindfulness therapy for people with psychotic disorders was developed. However, clinicians and researchers are cautious given case reports in which extensive meditation provoked psychotic symptoms in people with a psychotic disorder. The purpose of this study was to examine the feasibility, adverse effects and possible favourable effects of mindfulness-based therapy (MBT) in people...
Dragt S, Nieman DH, Schultze‐Lutter F, van der Meer F, Becker H, de Haan L, Dingemans PM, Birchwood M, Patterson P, Salokangas RKR, Heinimaa M, Heinz A, Juckel G, Graf von Reventlow H, French P, Stevens H, Ruhrmann S, Klosterkötter J, Linszen DH, on behalf of the EPOS group. Cannabis use and age at onset of symptoms in subjects at clinical high risk for psychosis. Objective: Numerous studies...
OBJECTIVE: The aim of the present study was to gain more insight into the positive and negative effects of cannabis in the prodromal phase of schizophrenia and in the ultra-high-risk (UHR) state for psychosis. METHOD: A theory-driven questionnaire was used to examine subjective effects in the prodromal phase in male subjects with a recent onset of schizophrenia or related disorder (n = 52) and...
As detailed elsewhere in this book (Chapter 3), cannabis has been used for centuries to produce euphoria and relaxation as desired mental effects. However, adverse effects of intoxication with cannabis include anxiety and panic (Thomas, 1996; Reilly et al. , 1998), depression (Bovasso, 2001; Patton et al. , 2002: see Chapter 4), and impairment in certain domains of cognitive function (see...