A clinical study to compare the safety and effectiveness of two different dose ranges of risperidone solution in the treatment of adolescents with a diagnosis of schizophrenia.

This is a clinical study of an investigational drug called risperidone in the treatment of schizophrenia in adolescents. Initially children (age 2 to 12 yrs) and schizophreniform subjects were also allowed but excluded following protocol amendment.

The study will include approximately 260 patients aged 13 to 17 years with a diagnosis of schizophrenia. Subjects will be randomly assigned to one of two groups on enrollment and will be given risperidone as an oral solution each day for 8 weeks at doses within one of two dose different ranges, according to the assigned study group.

Initially the two dose range were 0.15-0.4 mg/day and 1.5-4mg/day but were changed in protocol amendment to evaluate the maximum tolerated dose with a minimum of 3.5mg/day and maximum of 6mg/day (resp. 0.35 and 0.6mg/day in low dose treatment arm) Risperidone lower dose (0.35-0.6 mg/day [subjects >=50kg] or 0.007-0.012 mg/kg/day [subjects <50 kg]) as 0.1 mg/mL oral solution or risperidone higher dose (3.5-6 mg/day [subjects >=50 kg] or 0.07-0.12 mg/kg/day [subjects <50 kg]) as 1 mg/mL oral solution for 8 weeks. Daily dose can be given all at once or through 2 administrations (in morning and evening); the dose is increased based on efficacy and tolerability.

Inclusion Criteria:

• Subjects will be eligible for study enrollment if they: are adolescents between the ages of 13 and 17 years
• have a confirmed diagnosis of schizophrenia and are suffering from an acute episode
• provide their assent and parental informed consent to participate
• are otherwise relatively healthy on the basis of a medical and physical examination
• and are able to be in-patients for approximately 2 weeks.

Exclusion Criteria:

• Subjects will be excluded from the study if they: meet the criteria for psychiatric disorders other than schizophrenia
• have moderate or severe mental retardation
• fail to respond to treatment with at least two typical or atypical antipsychotics
• have a history of substance dependence within the 3 months before screening
• are considered at risk for suicidal or violent behavior
• have a seizure disorder
• have a history of neuroleptic malignant syndrome, similar encephalopathic syndrome, or tardive dyskinesia
• or receive prohibited medication within a specified period before screening.