Schizophrenia is a chronic psychiatric illness with periods of remission and relapse. Patients vary in the frequency and severity of relapse, time until relapse and time in remission. Discontinuation of antipsychotic medication is by far the most important reason for relapse. A possible method to optimize medication adherence is to treat patients with long-term, depot medication rather than oral medication. However, despite its apparent "common sense" this approach has neither been universally accepted by practicing psychiatrists nor unequivocally demonstrated in clinical trials. Therefore, in this study we aim to investigate possible advantages of depot medication over oral antipsychotics in an independently designed and conducted, randomized, pragmatic trial.

It remains unclear if depot medication can reduce relapse rates and improve clinical outcome when offered to all patients in need of continuation treatment with antipsychotics. Before we can conclude whether or not all schizophrenia patients could benefit from a switch to depot formulations, several questions remain to be answered. Is depot medication associated with better continuation rates and outcome? How are depot medications tolerated as compared to oral medication? In order to clarify these important issues we aim to perform a large multi-center trial in which schizophrenia patients in need of continuous treatment who are randomized 1:1:1:1 to two different depot preparations or to two different oral medications.

In this pragmatic, randomized, open label, multicenter, multinational comparative trial, schizophrenic patients aged 18 years or older, having experienced the first psychosis between 6 months and 7 years ago,with an indication (patient or physician initiated) to receive medication or to switch to another antipsychotic drug, will enter the study.

The study duration will be one month for the medication switch and then a follow-up of 18 months. Patients having refused to take part in the study will be asked to give consent and participate in a naturalistic follow-up, during which they will be followed with the Clinical Global Impression list (CGI) as closely related to the study schedule as possible, unless they also refuse this.

Inclusion Criteria:

1. Diagnosis of schizophrenia as defined by DSM-IV-R (Diagnostic and Statistical Manual) as determined by the M.I.N.I.plus

2. Age 18 or older.

3. 3. The first psychosis occurred at least 6 months and no more than 7 years ago.*

4. If patients are using an antipsychotic drug, a medication switch is currently under consideration.

5. Capable of providing written informed consent

   • Time of first psychosis is defined as the first contact with a health care professional in relation to psychotic symptoms.

Exclusion Criteria:

1. Intolerance / hypersensitivity to both* of the drugs (including active substances, metabolites and excipients) in this study including oral paliperidone and aripiprazole and/or hypersensitivity to risperidone.
2. Pregnancy or lactation.
3. Patients who are currently using clozapine.
4. Patients who do not fully comprehend the purpose or are not competent to make a rational decision whether or not to participate.
5. Patients with a documented history of intolerance to both* of the study medications and/or a documented history of non-response to a treatment with both* study drugs of at least 6 weeks within the registered dose range.7. Patients who have been treated with an investigational drug within 30 days prior to screening.

8. Simultaneous participation in another intervention study (neither medication or psychosocial intervention).

* If intolerance/hypersensitivity or non-response in the past to one of the compounds is documented, the patient can still participate; however, randomization will take place by blocking that specific compound. That is, the patient will be randomized on either the oral or the depot arm of the other compound. This procedure of blocking one compound is also accepted for patients who have experienced too many side effects to one of the compounds in the past, as documented in the patient's medical record. The decision to block that specific compound for randomization in these cases is up to the discretion of the treating physician who will carefully balance this decision and clearly document it in the medical record.