Genetic aspects of manic-depressive disease in family practice.

Bipolar affective disorder (manic-depressive disease) is a mental disturbance characterized by phases of both depression and mania. Mania is essential to the diagnosis and is characterized by elevated mood, flight of ideas, and increased psychomotor activity. Current psychiatric literature not only shows that this disease is familial but has also demonstrated, through linkage studies, that an X-linked dominant mode of inheritance adequately explains the strong prevalence of bipolar affective disorder in some families. The family discussed here shows many of the known clinical aspects of bipolar affective disorder. It serves as an example consistent with the X-linked dominant mode of inheritance. Knowledge of the genetic background of this disease aids the family physician by helping to identify members of the family likely to have acquired this condition. The family physician can then look for future problems in them and in their offspring, leading to earlier diagnosis and more effective management. Thus, a member of a bipolar family with supposed unipolar illness (depression only) might be better served with the prophylactic use of lithium carbonate because of his likelihood of possessing a bipolar genotype. The prophylactic use of this drug has been shown effective in reducing the frequency, duration, and intensity of both manic and depressive mood swings.