Psychopathological correlates of dopaminergic disturbances in major depression

In a recent report, we confirmed the role of dopamine in the pathophysiology of depression by demonstrating a blunted response of growth hormone (GH) to apomorphine, a selective dopaminergic agonist, in endogenous depressive patients. Few data are available on the possible psychopathological correlates of disturbances in the apomorphine test. In this study, we assessed the relationship between GH response to apomorphine and the Minnesota multiphasic personality inventory (MMPI) scales in a sample of 20 major depressive inpatients. The GH response (area under the curve) after apomorphine injection was positively correlated with the social introversion scale scores (r = 0.56, df = 19, p less than 0.01) and the anxiety scale scores (r = 0.45, df = 19, p = 0.04). These results suggest dopaminergic overactivity in anxious psychopathology rather than in depressive psychopathology. The relationship between the social introversion scale score and the apomorphine test is in agreement with the dopaminergic hypothesis of schizophrenic disorders.