Conrad O. Iyegbe

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Schizophrenia is an idiopathic mental disorder with a heritable component and a substantial public health impact. We conducted a multi-stage genome-wide association study (GWAS) for schizophrenia beginning with a Swedish national sample (5,001 cases and 6,243 controls) followed by meta-analysis with previous schizophrenia GWAS (8,832 cases and 12,067(More)
BACKGROUND The risk of individuals having adverse effects from drug use (eg, alcohol) generally depends on the frequency of use and potency of the drug used. We aimed to investigate how frequent use of skunk-like (high-potency) cannabis in south London affected the association between cannabis and psychotic disorders. METHODS We applied adjusted logistic(More)
BACKGROUND Cannabis use is associated with an increased risk of psychosis. One study has suggested that genetic variation in the AKT1 gene might influence this effect. METHODS In a case-control study of 489 first-episode psychosis patients and 278 control subjects, we investigated the interaction between variation at the AKT1 rs2494732 single nucleotide(More)
The relatively high heritability of schizophrenia suggests that genetic factors play an important role in the etiology of the disorder. On the other hand, a number of environmental factors significantly influence its incidence. As few direct genetic effects have been demonstrated, and there is considerable inter-individual heterogeneity in the response to(More)
Both cannabis use and the dopamine receptor (DRD2) gene have been associated with schizophrenia, psychosis-like experiences, and cognition. However, there are no published data investigating whether genetically determined variation in DRD2 dopaminergic signaling might play a role in individual susceptibility to cannabis-associated psychosis. We genotyped(More)
By analyzing the whole-exome sequences of 4,264 schizophrenia cases, 9,343 controls and 1,077 trios, we identified a genome-wide significant association between rare loss-of-function (LoF) variants in SETD1A and risk for schizophrenia (P = 3.3 × 10(-9)). We found only two heterozygous LoF variants in 45,376 exomes from individuals without a neuropsychiatric(More)
BACKGROUND Failure to account for the etiological diversity that typically occurs in psychiatric cohorts may increase the potential for confounding as a proportion of genetic variance will be specific to exposures that have varying distributions in cases. This study investigated whether minimizing the potential for such confounding strengthened the evidence(More)
Genetic association studies investigating the association between genes of serotonergic and dopaminergic systems and behavioral and psychological symptoms in dementia (BPSD) are contradictory. We have utilized 1008 probable Alzheimer's disease (AD) patients from the UK and used the 12-item Neuropsychiatric Inventory. We applied a multiple(More)
BACKGROUND Genome-wide association studies (GWAS) have identified several loci associated with schizophrenia and/or bipolar disorder. We performed a GWAS of psychosis as a broad syndrome rather than within specific diagnostic categories. METHODS 1239 cases with schizophrenia, schizoaffective disorder, or psychotic bipolar disorder; 857 of their unaffected(More)
BACKGROUND What determines inter-individual variability to impairments in behavioural control that may underlie road-traffic accidents, and impulsive and violent behaviours occurring under the influence of cannabis, the most widely used illicit drug worldwide? METHOD Employing a double-blind, repeated-measures design, we investigated the genetic and(More)