A recent head-to-head study by Savitz et al compared paliperidone extended-release (ER) in three flexible doses (3, 6, or 9 mg/day) with aripiprazole in three flexible doses (5, 10, or 15 mg/day).14 The primary efficacy measure was the mean change in PANSS total score. Responders were defined as those patients who achieved a 20% or greater reduction in the PANSS total score from baseline to endpoint. After 8 weeks of treatment, there was no significant difference between the groups in either the primary efficacy measure or in the responder rate (69.7% versus 76.3%). The most common (>10% of patients) treatment-emergent adverse events for paliperidone ER were akathisia, headache, somnolence, tremor, and weight gain, and for aripiprazole, adverse events were worsening of schizophrenia and somnolence. The 8-week acute treatment study was followed by an 18-week double-blind maintenance period for a total trial duration of 26 weeks. At the endpoint on week 26, no significant differences between treatment groups emerged, but response rates increased slightly in both groups (76.8% versus 81.6%).