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Background: It has been suggested that patients with bipolar disorder may have an increased sensitivity to dopaminergic (DA) compounds. This was investigated by measuring growth hormone (GH) or prolactin (PRL) response to apomorphine (APO), a dopamine receptor agonist, in patients with bipolar depression, unipolar depression and control subjects. Methods: Fourteen patients in an episode of bipolar depression (BP), 15 in an episode of unipolar depression (UP) and 19 age- and gender-matched control subjects (C) participated. The growth hormone (GH) and prolactin (PRL) responses to subcutaneous administration of 0.005 or 0.008 mg/kg APO were measured over 2 h. Results: The rise in GH was greater with the higher APO dose. Both the GH rise and the PRL fall following APO were similar in BP, UP and C. Neither the GH or PRL responses in BP and UP were affected by successful treatment of the depressive episode. Conclusion: Our findings do not indicate an altered sensitivity of DA neurones in the hypothalamic–pituitary system in either bipolar or unipolar depression. [Copyright &y& Elsevier]

Objective: Hyperintensities in the white matter of the brain (DWH) and in the periventricular area (PVH) seen on magnetic resonance imaging (MRI) have been reported to be more frequent in patients with bipolar disorder (BP) than in normal subjects. To examine this further we compared MRI of patients with BP with age-matched patients with major depressive disorder (unipolar depression, UP) and healthy control subjects. Methods: T2 weighted axial and coronal brain MRI scans were obtained from 13 patients in the depressive phase of BP, 11 with current UP and 19 age-matched control subjects. The degree of DWH and PVH present in each scan was determined using a standardized scoring method. Results: The PVH ratings were similar in the three groups of subjects. However, proportionately more BP patients had higher DWH scores than either UP patients or controls. Although this difference did attain statistical significant, a main effect of age was noted. Further, subjects over the age of 50 were under-represented in the UP group. Conclusions: Notwithstanding the small total sample size and relative lack of older subjects in the UP group, the fact that almost twice as many BP patients showed more severe DWH suggests that patients with BP may be more vulnerable to develop these changes than UP patients and healthy controls. [ABSTRACT FROM AUTHOR]