LITHIUM RESPONSE AND GENETICS OF AFFECTIVE-DISORDERS

The authors have carried out an investigation of psychiatric morbidity in families of patients who responded and failed to respond to long-t erm lithium treatment. The study included 121 probands with RDC primar y affective disorders and 903 first-degree relatives and spouses. Seve nty-one probands were responders and 50 were nonresponders to long-ter m lithium treatment. Extended to 20 years, the follow-up of patients a nd their families provided substantial information relevant for the di agnosis and reliable assessment of lithium response. The diagnoses wer e based on all available information, SADS-L interviews and RDC criter ia. The principal statistical methods were survival analysis and Cox r egression analysis. The results revealed a significantly higher freque ncy of bipolar disorder in the relatives of lithium responders (3.8% v s. O%), Schizophrenia was more common in the families of nonresponders (2.4% vs. 0.3%). There were no significant differences in the rates o f other psychiatric disorders. Both family history and the proband's d iagnosis contribute independently to predicting response to long-term lithium.