Clinical characteristics of schizophrenia in multiply affected Spanish origin families from Costa Rica.

Sixty-six families from Costa Rica with multiply ill sets of siblings were examined in detailed clinical evaluations and compared with 59 similarly evaluated families from the USA. Eighty-six unrelated Costa Rican individuals with a schizophrenia spectrum diagnosis and no other ill siblings were an additional comparison group. This study was undertaken to examine whether schizophrenia in Costa Rica has similar clinical and demographic characteristics to that in the USA, whether a homogeneous population such as that in Costa Rica might harbor a specific definable subtype, and whether singletons have similar or differing characteristics from individuals in multiplex families. Overall, schizophrenia in Costa Rica is similar to that in any other geographic location. The same symptoms, sex ratio and age of onset characteristics predominate. However, there was significantly less prevalence of affective symptoms (depression and mania) and drug abuse among the Costa Rican multiplex families by comparison with those from the USA. The families with only one ill member from Costa Rica had significantly more alcohol abuse than the multiply affected families. Within multiplex families (both USA and Costa Rica), age of onset was found to have a familial component. Family sibship size was significantly greater in Costa Rica than the USA for the generation with illness studied. However, these siblings had overall fewer children. In Costa Rica, the male but not the female siblings with schizophrenia had reduced fecundity compared with their well siblings. These families from Costa Rica will be used in further molecular genetic studies to determine whether the illness etiology can be traced to one or more specific genetic linkages.