A neuroendocrine study of serotonin function in depressed stroke patients compared to non depressed stroke patients and healthy controls

Abstract

Objectives: We employed a neuroendocrine challenge paradigm to study serotonergic abnormalities associated with poststroke depression. Method: Twelve depressed stroke patients (major depression N=5, minor depression N=7), 8 nondepressed stroke patients and 12 healthy volunteers completed a single-blind, placebo-controlled, challenge tests. Baseline cortisol (CORT) and prolactin (PRL) values, and these hormonal responses to 30 mg of oral d-FEN and placebo over a 4 hour period were measured in the three groups. Results: There were intergroup differences for baseline adjusted PRL responses (change scores from baseline) to d-FEN (group effect F=4.38, df=2,29, p=0.02) while these responses to placebo were comparable between groups (group effect F=1.82, df=2,29, p=0.18). Peak PRL responses (post d-FEN maximal PRL change from baseline scores) in depressed stroke patients were significantly greater than in nondepressed patients ( p=0.005) but comparable to healthy normals ( p=0.47). However, these responses between major and minor depression were not significant ( p=0.34). There was a trend suggesting a negative correlation between peak PRL response and severity of depression ( p=0.056). Depressed patients were younger than the controls ( p=0.054). Also, the depressed group was more functionally impaired ( p=0.04) and more likely to have right-sided lesions ( p=0.009) compared with the nondepressed group. Differences in baseline adjusted PRL changes between depressed and nondepressed groups became non significant when the influence of laterality of lesions was covaried, whereas covariation of functional scores and age did not alter the significance. CORT responses did not show intergroup differences. Limitations: The study group was small and was heterogenous in lesion characteristics, time since stroke and type of depression. A fixed-order design was used in the challenge test paradigm. Conclusions: When laterality of stroke lesion was taken into account, depressed and nondepressed stroke patients did not differ in PRL responses to d-FEN.