CSF Somatostatin in Affective Illness

Somatostatin is a hypothalamic tetradecapeptide with many actions. We investigated a potential role for somatostatinergic neuron dysfunction in affective disorder by measuring somatostatin in the CSF of 47 patients with affective illness and of 39 normal volunteers. Medication-free depressed patients showed significantly lower levels of CSF somatostatin than normal volunteers (P less than .001) or patients during the improved state (P less than .01). A significant inverse correlation was observed between somatostatin and the duration of sleep on the night of the lumbar puncture. We also observed significant correlations between somatostatin and 5-hydroxyindoleacetic acid and norepinephrine in the CSF. Also noted were the significance of depression-related decreases in CSF somatostatin in relation to information about central somatostatin secretion, reported abnormalities of somatostatin activity, and potential interactions between alterations in somatostatin activity and the pathophysiology of depression.