Open-label Study of Flexible-dose Paliperidone ER (Extended Release) to Treat Adolescent Schizophrenia.

The purpose of this open-label study is to evaluate the long-term (6-month) safety and tolerability of extended-release paliperidone, an atypical antipsychotic, given in flexible dosages to adolescents with schizophrenia.

This is a 6-month, open-label study (the patient, investigator, and sponsor know the study drug and dosage being taken by the patient) of the safety and tolerability of flexible-dose (1.5 to 12mg per day), extended-release (ER) paliperidone in adolescents with a diagnosis of schizophrenia. Patients who have completed study R076477PSZ3001 or who discontinued from that study because of lack of efficacy but completed a minimum of 21 days of the study may enter this study. Patients may also enter this study directly without participating in R076477PSZ3001. This study consists of a 21-day screening and washout phase (to discontinue and "wash out" any medication not allowed in the study), an open-label treatment phase of up to 26 weeks during which all patients will take oral paliperidone ER every day, and a post-treatment phase consisting of a follow-up visit completed 1 week after a patient has received the final dose of paliperidone ER. The study, including the screening and posttreatment phase, will last approximately 30 weeks. Screening and washout may be conducted while a patient is either an inpatient or an outpatient. Safety will be assessed by laboratory measurements (chemistry, liver function tests, hematology, hormone, lipid assessments, prolactin \[blinded\], urinalysis, and urine drug screens); body weight, height, and waist circumference measurements; ECGs; and physical examinations (including Tanner staging). The Abnormal Involuntary Movement Scale (AIMS), Barnes Akathisia Rating Scale (BARS), and Simpson Angus Rating Scale (SAS) will be used to assess extrapyramidal symptoms (EPS) and dyskinesias. Adverse events will be monitored including psychiatric adverse events of interest (i.e., suicide and related phenomena, homicidal ideation, depressed mood, and worsening of psychosis) that may be associated with paliperidone ER in this population. The primary aim of this study is to evaluate the long-term (6-month) safety and tolerability of paliperidone ER in adolescents with schizophrenia. As exploratory secondary aims, the study will assess the effect of paliperidone ER on the long-term symptoms of schizophrenia as measured by the changes in the Positive and Negative Syndrome Scale for Schizophrenia (PANSS) scores, the global improvement in severity of illness as measured by the Clinical Global Impression-Severity (CGI-S) scale, the benefits in psychological, social, and school functioning as measured by the Children's Global Assessment Scale (CGAS), the changes in multiple domains of cognitive functioning measured by the modified Measurements and Treatment Research to Improve Cognition in Schizophrenia (MATRICS) assessment battery, and the effect on sleep as measured by the sleep Visual Analog Scale (VAS). Patients begin the study at 6.0 mg/day of oral paliperidone ER. If a higher dosage is needed, the dosage will be increased (in increments of 3 mg/day not more frequently than once every 5 days) to 12 mg/day. If the 6.0 mg/day dosage is not well tolerated, the dosage may be decreased (not more frequently than once every 5 days) to 3.0 mg/day or 1.5 mg/day. Patients will be dosed for up to 6 months.

Eligibility Criteria:
Inclusion Criteria:

* Meets the DSM-IV criteria for schizophrenia, otherwise physically healthy
* Weight \>=63.9 pounds (29 kg)
* Must not be a danger to self or others and must have family support available to be maintained as outpatients
* Responsible adult must be available to accompany the patient to the investigational site at each visit.

Exclusion Criteria:

* Meets the DSM-IV criteria for dissociative disorder, bipolar disorder, major depressive disorder, schizoaffective disorder, schizophreniform disorder, autistic disorder, or primary substance-induced psychotic disorder
* mild, moderate, or severe mental retardation
* History of substance dependence (including alcohol, but excluding nicotine and caffeine) according to the DSM-IV criteria in the 3 months before screening
* pregnancy (for females)
* History or presence of circumstances that may increase the risk of the occurrence of torsade de pointes or sudden death in association with the use of drugs that prolong the QTc interval.