Successful treatment for obsessive-compulsive disorder with addition of low-dose risperidone to fluvoxamine: implications for plasma levels of catecholamine metabolites and serum brain-derived neurotrophic factor levels.

The authors report on the successful treatment of obsessive-compulsive disorder (OCD) in three patients with the addition of risperidone to ongoing fluvoxamine treatment. Plasma homovanillic acid (HVA), but not 3-methoxy-4-hydroxyphenylglycol (MHPG) levels decreased after risperidone administration, and plasma levels of fluvoxamine did not change. In addition, serum brain-derived neurotrophic factor (BDNF) levels were not altered after the recovery from obsessive-compulsive symptoms, indicating that serum BDNF levels might not predict the patient's response to risperidone treatment. Taken together, a combination treatment of risperdone and fluvoxamine might improve obsessive-compulsive symptoms. In short, fluvoxamine enhances the activity of the serotonergic system by inhibiting serotonin transporters, and risperidone decreases that of the dopaminergic system by blocking D2 receptors.