Low CSF concentration of a dopamine metabolite in tobacco smokers

Objective: To screen for dopaminergic abnormalities in tobacco smokers and patients with posttraumatic stress disorder (PTSD), the authors determined serial CSF and plasma concentrations of the dopamine metabolite homovanilli c acid (HVA). Method: Continuous subarachnoid sampling was used to obtain 3 7 serial CSF samples over 6 hours in 13 normal volunteers and II patients w ith combat-related PTSD; 10 smoked and 14 had never smoked. The smokers wer e abstinent from tobacco for 11 to 17 hours. Results: The smokers had marke dly lower CSF, but not plasma, HVA levels. Their CSF HVA concentrations ave raged only 54% of the concentrations of the nonsmokers, independent of diag nosis. Conclusions: Smokers' low CSF concentrations of HVA may be associate d either with chronic inhalation of nicotine or other constituents of tobac co smoke or with acute abstinence. Any possible basal dopaminergic abnormal ities in patients with PTSD are small relative to the abnormalities associa ted with smoking.