BACKGROUND: We evaluated the cross-sectional and longitudinal association of measures of both insight and attitudes toward medication to outcomes that included psychopathology and community functioning. METHODS: Clinical Antipsychotic Trial of Intervention Effectiveness (CATIE) was a large 18-month follow-up study pharmacotherapy of people with schizophrenia. Insight was measured using the Insight and Treatment Attitudes Questionnaire and attitudes toward medication by the Drug Attitude Inventory. Widely known scales were used to assess symptoms of schizophrenia and depression and community functioning. Medication adherence was globally assessed by the treating psychiatrist using several sources of information. Bivariate correlations and mixed model regression analyses were used to test the relationship of insight and medication attitudes to outcomes at baseline and during the follow-up period. Regression models were used to evaluate the relationship between change in insight and medication attitudes and changes outcomes. RESULTS: There was a significant relationship at baseline between insight and drug attitudes and symptoms of schizophrenia and depression, as well as with community functioning. Higher levels of insight at baseline were significantly associated with lower levels of schizophrenia symptoms at follow-up while more positive medication attitudes were significantly associated with both lower symptom levels and better community functioning. Change in insight scores over time was associated with declining schizophrenia symptoms but increasing levels of depression. Change toward more positive medication attitudes was associated, independently of changes in insight, with significant decreases in psychopathology, improvement in community functioning, and greater medication compliance. CONCLUSION: Greater patient understanding of their illness and more positive attitudes toward medication may improve outcomes. Educational interventions that affect these attitudes may be an important part of psychosocial rehabilitation and/or recovery-oriented services.