Antecedents to first episode psychosis and mania: Comparing the initial prodromes of schizophrenia and bipolar disorder in a retrospective population cohort.

objectiveWe aim to compare the psychiatric antecedents of schizophrenia (SZ) and bipolar disorder (BD).

methodsUsing the Rochester Epidemiology Project, we searched for residents of Olmsted County that had a diagnosis of SZ or BD. We confirmed each case using DSM-5 criteria and obtained the psychiatric antecedents.

resultsWe identified 205 cases with first episode psychosis or mania (SZ = 131; BD = 74). The mean age at first visit for mental health reasons was 12.3 ± 6.3 years for SZ and 13.9 ± 5.6 years for BD. The duration of the initial prodrome (time from first mental health visit to first episode) was similar for both groups (SZ 8.3 ± 6.2 years vs BD 7.3 ± 5.9 years). We found that SZ and BD have overlapping antecedents, but SZ was more common in males and in foreign born and had more learning deficits before the first episode. BD was more common in white population and had higher rates of depressive and adjustment disorders prior to first episode. BD also had more affective symptoms, nightmares, and panic attacks before the first episode. Both groups had similarly high rates of substance use (SZ 74 % vs BD 74.3 %), prescription of antidepressants (SZ 46.6 % vs BD 55.4 %) and stimulants (SZ 30.5 % vs BD 22.9 %).

conclusionsThe psychiatric antecedents of SZ and BD usually start during adolescence, overlap, and present in unspecific ways. The initial prodromes are more alike than distinct. Further studies are encouraged to continue looking for specific factors that distinguish the antecedents of these two disorders.