CSF neurotransmitter metabolites and neuropsychiatric symptomatology in patients with normal pressure hydrocephalus

Patients with normal pressure hydrocephalus (NPH) may exhibit certain neuropsychiatric symptomatology, possibly related to alterations in central neurotransmitter activity. The aim of this study was to relate psychiatric distress, as expressed by the scores in the SCL-90 subscales, to CSF levels of the main metabolites of noradrenaline (MHPG), serotonin (5-HIAA), and dopamine (HVA) in NPH patients. The metabolite levels were estimated in CSF samples taken during the tap test in 19 patients with probable NPH, and compared to 19 sex- and age-matched controls. Cognitive impairment was evaluated by the MMSE. Compared to controls, NPH patients had similar MHPG and 5-HIAA levels, and significantly elevated HVA levels, a notable difference from patients with dementias. There were no significant correlations of metabolite levels to the scores in the nine SCL-90 subscales. MMSE score was not related either to metabolite levels, or to the SCL-90 subscale scores. Patients scored higher than controls in most SCL-90 subscales, more pronounced being the difference in obsessive-compulsive symptomatology. Serotonergic neurotransmitter activity seems not to be altered in NPH patients, and this may explain the reported lack of beneficial effect of serotonergic drugs for obsessive-compulsive symptoms in NPH patients.