Intranasal desmopressin as an adjunct to risperidone for negative symptoms of schizophrenia: a randomized, double-blind, placebo-controlled, clinical trial.

Considering the role of neurohypophyseal peptides in normal development and function of higher cortical processes along with their proven abnormalities in schizophrenic patients, these pathways have recently attracted greater attention as treatment targets for schizophrenia. Desmopressin (DDAVP) is a synthetic analog of vasopressin. This study aimed to evaluate the efficacy and safety of DDAVP nasal spray as an adjunct to risperidone in improving negative symptoms of schizophrenia. In this randomized double-blind placebo-controlled clinical trial, forty patients aged 18-50 years with a DSM IV-TR diagnosis of chronic schizophrenia and a minimum score of 60 on positive and negative syndrome scale (PANSS) were equally randomized to receive DDAVP nasal spray (20mcg/day) or placebo in addition to risperidone for 8 weeks. Patients were partially stabilized and treated with a stable dose of risperidone (5 or 6mg/day) for at least four weeks prior to entry. Participants were rated by PANSS every two weeks and decrease in the PANSS negative subscale score was considered as our primary outcome. By the study endpoint, DDAVP-treated patients showed significantly greater improvement in the negative symptoms (P=0.001) as well as the PANSS total and general psychopathology subscale scores (P=0.005 and P=0.003; respectively) compared to the placebo group. Treatment group was the strongest predictor of changes in negative symptoms (β=-0.48, t=-3.67, P=001). No serious adverse event or fluid/electrolyte imbalance was reported in this trial. In conclusion, DDAVP nasal spray showed to be an effective and safe medication for improving negative symptoms in patients with chronic schizophrenia.