Cannabis-associated symptom profiles in patients with first episode psychosis and population controls

Abstract

ObjectiveThe 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.MethodThe authors analysed data from 901 patients and 1235 controls recruited across six countries, as part of the European Network of National Schizophrenia Networks Studying Gene-Environment Interactions (EU-GEI) study. Item response modelling was used to estimate two bifactor models, which included general and specific dimensions of psychotic symptoms in patients and psychotic experiences in controls. The associations between these dimensions and cannabis use was evaluated using linear mixed effects models analyses.ResultsIn patients, there was a linear relationship between the positive symptom dimension and the extent of lifetime exposure to cannabis, with daily users of high potency cannabis having the highest score (B=0.35; 95%CI 0.14 to 0.56). Moreover, negative symptoms were more common among patients who never used cannabis compared with those with any pattern of use (B=-0.27; 95%CI −0.42 to −0.12).In controls, psychotic experiences were associated with current use of cannabis but not with the extent of lifetime use.Neither patients nor controls presented differences in the depressive dimension related to cannabis use.ConclusionsThe extent of use of cannabis explains part of the heterogeneous distribution of positive and negative symptoms of FEP patients.

Validity and utility of Hierarchical Taxonomy of Psychopathology (HiTOP): I. Psychosis superspectrum

“…In the general population, it was associated with both elevated psychoticism and detachment, although the latter effect was weaker 48,172‐174 . In patients, cannabis use was associated with more severe reality distortion symptoms and was not consistently linked to other symptoms 175‐179 .…”

Schizophrenia polygenic risk score and cannabis use modify psychosis expression in first episode psychosis patients and population controls

“…Consistent with this methodology, we reported that transdiagnostic psychopathology at first episode psychosis (FEP) can be represented by a general psychosis factor (G), and five specific dimensions of positive (POS), negative (NEG), disorganization (DIS), manic (MAN), and depressive (DEP) symptoms (10). Similarly, a model composed of general and specific experience dimensions has been proposed to measure subclinical psychosis in the general population (11, 12). These conceptualizations statistically reflect a ‘bi-factor model’, where the general and specific dimensions account, respectively, for the unidimensional and multidimensional nature of the latent psychosis construct (13, 14).…”

“…Thus, we recently found evidence that cannabis-associated psychopathology at psychosis onset is characterised by high POS scores and low NEG scores (16). In relation to biological factors, symptom dimensions have been investigated in family, twin and adoption studies (17-22), overall showing that NEG or DIS symptoms had higher familial aggregation than other symptom dimensions.…”

“…We have previously reported findings from bi-factor models of 1) psychotic symptoms in a multinational FEP sample (10) and 2) psychotic experiences in controls representative of the population at risk in each catchment area (11). In the current study, we aimed to investigate the association between these phenotypes and genetic loading for SZ and BP, as summarised by i) SZ-PRS, ii) BP-PRS, iii) combined SZ & BP-PRS.…”

“…In the current study, we aimed to investigate the association between these phenotypes and genetic loading for SZ and BP, as summarised by i) SZ-PRS, ii) BP-PRS, iii) combined SZ & BP-PRS. We further explored whether the previously reported association of cannabis use with the POS dimensions (16) holds when taking into account SZ-PRS.…”