We should focus more on reducing or preventing specific environmental and lifestyle risk factors for schizophrenia, because genetic risk factors have no predictive capability whatsoever, according to a study in The Lancet Psychiatry.
The team of German researchers studied 750 male patients diagnosed with schizophrenia for whom they had genetic information as well as extensive background and clinical information about factors such as marijuana use, brain injuries, and traumatic experiences. They drew on the latest studies of genes and schizophrenia, and then evaluated which information was more useful for predictive purposes. “Specifically, we investigated the potential effect of schizophrenia risk alleles as identified in the most recent large genome-wide association study versus the effects of environmental hazards (ie, perinatal brain insults, cannabis use, neurotrauma, psychotrauma, urbanicity, and migration), alone and upon accumulation, on age at disease onset, age at prodrome, symptom expression, and socioeconomic parameters,” they wrote.
They found that environmental factors became a significant predictor of schizophrenia as the number, frequency and intensity of those factors increased. In contrast, they found that genetic risk factors “did not have any detectable effects.”
“These findings should be translated to preventive measures to reduce environmental risk factors, since age at onset of schizophrenia is a crucial determinant of an affected individual’s fate and the total socioeconomic cost of the illness,” the researchers concluded.
(Abstract) Accumulated environmental risk determining age at schizophrenia onset: a deep phenotyping-based study (Stepniak, Beata et al. The Lancet Psychiatry. November 2014. doi: 10.1016/S2215-0366(14)70379-7)