The purpose of this study is to explore tolerability, safety and effectiveness of flexibly dosed paliperidone extended release (ER) in participants with schizophrenia (psychiatric disorder with symptoms of emotional instability, detachment from reality, often with delusions and hallucinations, and withdrawal into the self) previously unsuccessfully treated with an oral antipsychotic medication.

This is a non-randomized (the study drug is not assigned by chance), single arm, multicenter (when more than one hospital or medical school team work on a medical research study) 6-month study. Participants can be transitioned to an effective dose of paliperidone ER from any oral antipsychotic medication due to lack of efficacy, lack of tolerability or safety, lack of compliance or other reason. A transition period of maximum 4 weeks will be allowed. Throughout the study, participants will receive flexible dose of 3 to 12 milligram (mg) of paliperidone once daily orally for 6 months. Adjustment of the dosage will be done at Investigator's discretion, based on the individual participant's clinical response and tolerability of the study drug dosages. Participants who complete this 6-month study and would like to continue will be eligible to be enrolled in an extension phase until paliperidone ER is available. The starting dose of the extension phase will be the same as at the end of the 6-month study and may be changed throughout the extension period. The extension phase will consist of a main extension phase (ending with an End of Main Extension Phase Visit) and a modified extension phase (ending with an End of Study Visit). Efficacy will primarily be evaluated by positive and negative syndrome scale (PANSS). Safety will primarily be evaluated by Extrapyramidal Symptom Rating Scale (ESRS).

Inclusion Criteria:

• Participant meets the Diagnostic and Statistical Manual of Mental Disorders (Edition 4) criteria for schizophrenia
• Participant is previously non-acute (on the same antipsychotic medication used for the treatment of schizophrenia and Clinical Global Impression-Severity [CGI-S] change less than or equal to 1 in the past 4 weeks before enrollment) and has been given an adequate dose of an appropriate oral antipsychotic for an adequate period of time prior to enrollment, but previous treatment is considered unsuccessful due to one or more of the following reasons: lack of effectiveness, lack of tolerability or safety, lack of compliance and/or other reasons to switch to another antipsychotic medication
• Participant is healthy on the basis of a physical examination and vital signs at screening
• Female participants must be postmenopausal for at least 1 year, surgically sterile, abstinent, or, if sexually active, agree to practice an effective method of birth control before entry and throughout the study
• Participants must be willing and able to fill out self-administered questionnaires

Exclusion Criteria:

• Participants on clozapine, any conventional depot neuroleptic or risperidone long-acting injection during the last 3 months
• Participants with serious unstable medical condition, including known clinically relevant laboratory abnormalities
• Participants with history or current symptoms of tardive dyskinesia (twitching or jerking movements that you cannot control in your face, tongue, or other parts of your body) and neuroleptic malignant syndrome (high fever, rigid muscles, shaking, confusion, sweating more than usual, increased heart rate or blood pressure, or muscle pain or weakness)
• Participants judged to be at high risk for adverse events, violence or self-harm
• Participants with a current use or known history (over the past 6 months) of substance dependence according to Diagnostic and Statistical Manual of Mental Disorders (Edition 4) Criteria