In the current issue of the Archives of General Psychiatry it was reported that in-utero exposure to influenza during the second trimester may increase the risk of adult major affective disorder. This seems to have particular importance to families who have shown a predisposition towards mental illness such as schizophrenia. I'd appreciate input from researchers and psychiatrists subscribing to this newsletter on how family members might be able to use this knowledge to reduce the incidence of schizophrenia in their future pregnancies (I'll include any info I receive in a future newsletter)

In the report in the Archives of General Psychiatry, Dr. Ricardo A. Machon of Loyola Marymount University in Los Angeles and a multinational team evaluated a group of adults who had been exposed in-utero to the 1957 influenza epidemic in Helsinki, Finland.

In an earlier study, these same researchers found a higher than expected incidence of schizophrenia in these subjects. Since adult affective disorder, like schizophrenia, has been proposed to have a neurodevelopmental origin, Dr. Machon and colleagues revisited their original data to look for an association between influenza exposure and major affective disorder.

The incidence of major affective disorders in the exposed cohort was significantly higher than in controls, 13% versus 2%. The significance of this relationship remained when population-based estimates were used. In addition, the influenza exposure effect appeared to be slightly stronger in men, "...although the rates of major affective disorder in women were similar."

The findings "...provide suggestive evidence for a neurodevelopmental genesis for a subgroup of major affective disorders in the second trimester," Dr. Machon explains. He adds, "It is conceivable that second-trimester neural developmental disturbance is associated with an increased likelihood of delusional symptomatology and absence of formal thought disorder and that the decompensation may take the form of schizophrenia or major affective disorder."

Arch Gen Psychiatry 1997;54:322-328.