The primary purpose of this study is to document the long-term safety of an oral formulation of risperidone in the treatment of children and adolescents with conduct and other disruptive behavior disorders. Data on the efficacy of the drug will also be collected. Only patients who were enrolled in the previous related study would be eligible to participate.

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/milliliter) 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.

Inclusion Criteria:

• Patients must have completed the double-blind study (CR002020)
• Patients must begin the present study within 7 days of taking the last dose of medication in the prior study (CR002020)

Exclusion Criteria:

• Patients with hypersensitivity or intolerance to risperidone
• Patients with extrapyramidal symptoms (EPS) not adequately controlled with medication
• History of neuroleptic malignant syndrome, a rare psychotropic-drug reaction, which may be characterized by confusion, reduced consciousness, high fever or pronounced muscle stiffness
• Significant and untreated or unstable medical illness such as diabetes, hypertension
• serious illness of the liver, kidney, or significant disturbances of the cardiac, pulmonary, gastrointestinal, endocrine, neurological system
• Pregnant or nursing females, or those lacking adequate contraception