Background Improving cognitive functioning in people with schizophrenia is a major treatment goal. In addition, interview-based measures have been developed to supplement performance-based assessments. However, few data are available regarding whether interview-based measures are sensitive to treatment-related changes. Methods Adult outpatients who met DSM-IV criteria for schizophrenia or schizoaffective disorder were randomized to 21days of double-blind treatment with lurasidone 120mg once daily (N=150) or ziprasidone 80mg BID (N=151). A similar proportion of patients completed the study on lurasidone (67.5%) and ziprasidone (69.3%). Study participants were assessed with the majority of the tests from the MATRICS Consensus Cognitive Battery (MCCB) and an interview-based assessment of cognitive functioning, the Schizophrenia Cognition Rating Scale (SCoRS). SCoRS ratings were based on the interviewer's best judgment, after interviews with the patient and a caregiver when available. The study was conducted from April 2006 to January 2007. Results There were no between-group treatment differences in performance on the MCCB or the SCoRS ratings. Lurasidone patients demonstrated significant within group-improvement from baseline on the MCCB composite score (p=0.026) and on the SCoRS (p<0.001), but ziprasidone patients did not improve on either the MCCB composite (p=0.254) or the SCoRS (p=0.185). At endpoint there was a statistical trend (p=0.058) for lurasidone to demonstrate greater improvement from baseline in SCoRS ratings. Improvements in interview-based aspects of cognition were not related to MCCB test changes, and had minimal correlations with changes in symptoms. Conclusions These data suggest that interview-based cognitive measures such as the SCoRS may be sensitive to changes after 3weeks of treatment in patients with schizophrenia. Lurasidone is being assessed further in ongoing clinical trials with additional outcome measures.