CSF neuropeptides in euthymic bipolar patients and controls.

Levels of vasopressin, somatostatin, neurotensin, vasoactive intestinal peptide, corticotrophin-releasing factor and adrenocorticotrophin in CSF were determined in lithium-treated and unmedicated euthymic bipolar patients and controls, in a search for a trait marker in affective disorder. No group differences in levels of these peptides were found. Highly significant positive correlations were found among these peptides (with the exception of neurotensin), suggesting that their presence in CSF is functionally significant, as opposed to the result of random diffusion from the interstitial space of the brain.