Platelet MAO, personality and response to lithium prophylaxis.

Patients with bipolar affective disorder and who were maintained on long lithium prophylaxis were evaluated retrospectively regarding response to lithium. Good responders to lithium prophylaxis were compared to non-responders and to normal controls on platelet MAO activity, and on psychological variables (Eysenck's extraversion, neuroticism, psychoticism and lie scale; Foulds' extrapunitiveness, intropunitiveness and dominance). Lithium responders, non-responders and normal controls had similar platelet MAO activity. There was a tendency for higher plasma lithium levels to be associated with higher platelet MAO activity in male patients but not in females. Lithium non-responders exhibited significant correlations between their platelet MAO activity and their test scores on psychoticism, and extraversion. Lithium non-responders, compared to responders and normals, showed abnormal personality profiles on neuroticism, and dominance.