Cerebrospinal fluid somatostatin, mood, and cognition in multiple sclerosis

Background: Cerebrospinal fluid (CSF) somatostatin (SS) levels have been shown to be decreased in multiple sclerosis (MS) during relapse as well as in disorders characterized by depression or cognitive impairment. Since MS is often associated with depression and cognitive impairment, we examined both the effect of course of illness on CSF SS as well as the variance in SS attributable to associated features (e.g., depression or cognitive impairment). Methods: Fifteen patients with chronic progressive MS participating in a 2-year cyclosporine trial underwent lumbar punctures for CSF SS at baseline and at 12 and 24 months. Additionally, patients were evaluated by neuropsychological testing, and physical disability and mood ratings. Baseline CSF SS levels were also obtained in a group of control subjects (n = 10). Results: At baseline, CSF SS levels were lower in MS patients than control subjects (p< .001). Decreaed CSF SS at 24 months was correlated with decreased cognitive performance on several measures and was best and significantly predicted by cognitive deterioration at 24 months. Conclusions: Our data support those from previous studies that found lower levels of CSF SS in MS during relapse and suggest that changes in CSF SS are related to the process responsible for diminished cognitive function in MS.