• To accumulate long-term safety data: incidence of adverse events and clinical evaluations (physical exam, laboratory tests) conducted throughout the trial.
  

• To asses long-term efficacy data: changes from baseline to 1 year in Conduct Problem subscale of N-CBRF; VAS-MS changes from baseline through 1 year; CGI-Severity subscale at every visit; C-GAS rated for global functioning at the endpoint.
  

This is an open-label study of an oral formulation of risperidone to be taken daily over 12 months by children and adolescents with conduct and other disruptive behavior disorders. It is an extension of a randomized, double-blind study (RIS-INT-79) comparing risperidone with placebo over 6 months in patients who had already shown response to the medication for a period of 12 weeks. Efficacy assessments include: the Conduct Problem subscale of the Nisonger Child Behavior Rating Form (N-CBRF), a measure of symptoms of conduct and other disruptive behavior disorders; Visual Analogue Scale for the most troublesome symptom (VAS-MS), a scale ranging from not troublesome to extremely troublesome; Clinical Global Impression-Severity of Illness (CGI-Severity), a measure of overall severity of illness; Children's Global Assessment Scale (C-GAS), as assessment overall functioning. Safety evaluations include incidence of adverse events, physical examinations, laboratory tests (biochemistry, hematology, and urinalysis), and electrocardiograms (ECGs).

Oral risperidone solution (1milligram/milliter) daily for 1year. For patients weighing at least 50kg, start dose is 0.5ml/day. At investigator's discretion, dose may be increased (maximum 1.5ml/d over 5 days). Patients under 50kg start at 0.25ml/d, increased, if required, to maximum 0.75ml/d.