0000000000469116
AUTHOR
Pak Sham
showing 6 related works from this author
FIRST EPISODE PSYCHOTIC PATIENTS WITH A HISTORY OF FREQUENT CANNABIS USE EXPRESS MORE POSITIVE SYMPTOMS AT ILLNESS ONSET THAN THOSE WHO NEVER USED CA…
2018
Background: Robust evidence has demonstrated that cannabis use increases the risk to develop psychotic disorders. However, a limited number of studies have investigated if and how cannabis use influences psychopathology profiles at first episode psychosis (FEP). Based on the evidence that dopamine dysfunction contributes to explain positive symptoms in psychosis, and that the main cannabis’ psychoactive component, Δ9-Tetrahydrocannabinol (THC), modulates the dopamine system, we hypothesise that: 1) positive symptoms at FEP are more common among psychotic patients who used cannabis compared with never users; 2) this association is a dose-response relationship. Methods: We analyzed a sample o…
IS THE ERA OF CANDIDATE GENES X CANNABIS USE REALLY DEAD?
2019
Background: Historically, gene X environment examinations in psychotic disorders have employed candidate gene methods and environmental determinants impacting on similar biological mechanisms. However, genome wide association studies (GWAS) show that many variants associated with schizophrenia have a modest effect size on risk. In this respect, it is unclear whether the effect of cannabis on psychosis phenotypes is modified by a few genes, e.g. those involved in dopamine signalling, or by the overall genetic susceptibility to schizophrenia. Indeed, candidate gene approaches might be complementary to GWAS to test gene X cannabis interaction. We aimed to investigate the interactive effects of…
Premorbid Adjustment and IQ in Patients With First-Episode Psychosis: A Multisite Case-Control Study of Their Relationship With Cannabis Use
2020
Abstract 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 Some authors suggest that cannabis-using patients may have been less cognitively impaired and less socially withdrawn in their premorbid life.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 countries, we examined the extent to which IQ and both early academic (Academic Factor [AF]) and social adjustment (Social Factor [SF]) are related to the lifetime frequency of cannabis use in both patients and controls. We expected a higher IQ and a better premorbid social adjustment in psychotic p…
JUMPING TO CONCLUSIONS AND FACIAL EMOTION RECOGNITION IMPAIRMENT IN FIRST EPISODE PSYCHOSIS ACROSS EUROPE
2018
Background Jumping to conclusions (JTC) is a well-established reasoning and data gathering bias found in patients with psychosis even at illness onset (First Episode Psychosis, FEP). Preliminary work in this field focused primarily on the association with delusions, although jumping to conclusions has also been found in non-deluded schizophrenia patients after remission, and in individual with at risk mental state. Moreover, psychotic patients tend to show impairments in social cognition, struggling in identifying, processing and interpreting social clues. Deficits in facial emotion recognition (FER) – a key component of the construct – represent a well-replicated finding in schizophrenia. …
BIOLOGICAL AND EPIDEMIOLOGICAL EXAMINATION OF TRANSDIAGNOSTIC AND SPECIFIC SYMPTOM DIMENSIONS AT PSYCHOSIS ONSET: FINDINGS FROM THE EUGEI STUDY
2018
Background Current diagnostic models of psychosis have been questioned since Kraepelin’s original dichotomy of dementia praecox and manic depression. Indeed, increasing evidence has suggested that a dimensional approach might be a valid alternative platform for research. However, while an increasing number of studies have investigated how environmental risk factors for affective and non-affective psychosis map onto symptom dimensions, only a few have examined these dimensions in relation to genetic variants as summarised by Polygenic Risk Score (PRS). Furthermore, no studies have examined the putative effect of PRS for Schizophrenia (SZ), Bipolar Disorder (BP), and Major Depressive Disorder…
DOES POLYGENIC RISK SCORE FOR SCHIZOPHRENIA IMPACT ON JUMPING TO CONCLUSIONS? PRELIMINARY FINDINGS FROM THE EU-GEI CASE-CONTROL STUDY
2019
Background: Jumping to conclusions (JTC) is a reasoning and data gathering bias that results in the tendency to require less evidence and make hasty decisions. Preliminary work on reasoning bias focused primarily on the association with delusions, although jumping to conclusions has also been found in non-deluded schizophrenia (SZ) patients. Literature to date has shown JTC as a well-established bias in psychosis even at First Episode Psychosis (FEP), after remission, and in individuals with at risk mental state. Furthermore, JTC has been found to be associated with proneness to psychotic-like experiences in the general population. In teresting findings showed also an association with lower…