Effect of the 5-HT2 antagonist mianserin on cognitive dysfunction in chronic schizophrenia patients: An add-on, double-blind placebo-controlled study

Preponderance of serotonin 5-HT2A antagonism over dopamine D2 blockade exerted by atypical antipsychotics may contribute to their cognitive-enhancing effect. In a double-blind placebo-controlled study we examined the effect of add-on mianserin (15 mg/day), an agent with marked 5-HT2A antagonism, on cognitive functioning in 30 chronic hospitalized DSM-IV schizophrenia patients stabilized on typical antipsychotics. The Automated Neuropsychological Assessment Metrics (ANAM) battery was used to assess learning, memory and sustained attention; Wisconsin Card Sorting Test (WCST) to assess executive function at baseline and endpoint (4 weeks). Clinical assessment included appropriate rating scales. The mianserin group overperformed the placebo group on selective ANAM memory/learning tests, reflected in moderate-to-high effect size values. No between-group differences were revealed in WCST and clinical ratings. Conclusions: Improved performance on selective neurocognitive tests with addition of the 5-HT2A antagonist mianserin to typical antipsychotics indicates a possible role of the 5-HT system in cognitive-enhancing effects. The effect of flexible doses of mianserin on cognitive deficits in a broader schizophrenia population merits further investigation.