The objective of this study was to determine if early changes in triglycerides and weight may be useful in predicting longer-term changes in weight and other metabolic parameters. Data were from three 24- to 28-week randomized, controlled studies comparing olanzapine to ziprasidone or aripiprazole for treatment of schizophrenia. Analyses were restricted to completers with fasting laboratory data at all protocol specified time points. Analyses were primarily descriptive and included mean changes and categorical outcomes. In all treatment groups, participants who did not experience a 20 mg/dL or greater increase in triglycerides at early time points were unlikely to experience a change of 50 mg/dL or more in triglycerides after 6 months. Negative predictive values were 83% to 95%. However, early change in triglycerides was not useful for predicting later change in glucose, cholesterol, or weight. Similarly, early weight change gave robust negative predictive values for longer-term weight change (≥10 kg), but not for change in glucose or cholesterol. Lack of early elevation in triglyceride concentrations was predictive of later lack of substantial increase in triglycerides in olanzapine-, ziprasidone-, and aripiprazole-treated participants. Lack of early elevation in weight was predictive of later lack of substantial increase in weight in all 3 treatment groups. Early monitoring of triglyceride concentrations and weight may help clinicians assess risk that individuals will experience significant increase in triglycerides or weight gain, allowing assessments of potential risks and benefits earlier in treatment. Clinical monitoring is advised throughout treatment for all patients.