A recent review of genetic and population studies reveals that premorbid cognitive deficits in schizophrenia, such as lower IQ, are largely due to neurodevelopmental disruptions rather than inherited genetic variants that directly increase schizophrenia risk. The findings suggest that non-familial factors, including rare genetic mutations and environmental influences, play a significant role in both cognitive impairments and schizophrenia risk.

A recent review outlines the genetic complexity of schizophrenia, highlighting nearly 300 common genetic variants and over 20 rare variants linked to the disorder. Researchers emphasize that schizophrenia's genetic basis is multifaceted, involving multiple genes rather than a single cause. Environmental factors like lifestyle and stress also play crucial roles. This understanding underscores the need for comprehensive research to develop better interventions for schizophrenia.