This study compares the efficacy and effectiveness of two of the second-generation antipsychotics (SGAs) most used in our society in the treatment of schizophrenia (Aripiprazole and Risperidone) and the investigators do within an assistance program of early-stage psychosis individuals of the Community of Cantabria, clinical reference for the treatment of this disease in the Spanish Autonomous Community. Patients are included in a prospective naturalistic study, open flexible-doses and randomized into one of two possible patterns of treatment that includes the protocol.

At present there is no evidence of which antipsychotic treatment would be the choice for treating the appearance of a non-affective psychotic disorder. There are a number of second-generation antipsychotic drugs that have proven effective in controlling positive symptoms of the disease but carry a number of variable side effects so there is no evidence on the treatment of choice in the market. Few studies try to assess the adhesion of a first episode of psychosis as prolonged treatment in time. Thus the development of experimental studies comparing the effectiveness of such treatments in clinical practice is of high interest for clinical psychiatrists.

Study setting and financial support: data for the present investigation are being obtained from an ongoing epidemiological and three-year longitudinal intervention program of first-episode psychosis (PAFIP) conducted at the outpatient clinic and the inpatient unit at the University Hospital Marqués de Valdecilla, Spain. Conforming to international standards for research ethics, this program was approved by the local institutional review board. Patients meeting inclusion criteria and their families provide written informed consent to be included in the PAFIP. The Mental Health Services of Cantabria provided funding for implementing the program. None pharmaceutical company supplied any financial support to it.

Study design: this is a flexible-dose study of two neuroleptics (Aripiprazole and Risperidone) assigned at aleatory ratio 1:1. Rapid titration schedule (5-day), until optimal dose is reached, is a rule used unless severe side effects occur. At the treating physician's discretion, the dose and type of antipsychotic medication could be changed based on clinical efficacy and the profile of side effects during the follow-up period. Antimuscarinic medication, Lormetazepam and Clonazepam are allowed for clinical reasons. No antimuscarinic agents are administered prophylactically. Antidepressants (Sertraline) and mood stabilizers (lithium) are permitted if clinically needed.

Clinical assessment: the severity scale of the Clinical Global Impression (CGI) scale, the Brief Psychiatric Rating Scale (BPRS), the Scale for the Assessment of Positive symptoms (SAPS) and the Scale for the Assessment of Negative symptoms (SANS) are used to evaluate symptomatology. To assess general adverse event experiences the Scale of the Udvalg for Kliniske Undersogelser (UKU), the Simpson-Angus Rating Scale (SARS) and the Barnes Akathisia Scale (BAS) are used. The same trained psychiatrist (BC-F) completed all clinical assessments.

Inclusion Criteria:

• Experiencing their first episode of psychosis (First Episode of Psychosis is defined as that psychopathological state in which for the first time and regardless of its duration, the patient has enough severe psychotic symptoms to allow a diagnosis of psychosis, having received no specific psychiatric treatment for him).
• Living in the catchment area (Cantabria).
• No prior treatment with antipsychotic medication or, if previously treated, a total life time of adequate antipsychotic treatment of less than 6 weeks.
• Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV) criteria for brief psychotic disorder, schizophreniform disorder, schizophrenia, or schizoaffective disorder.

Exclusion Criteria:

• Meeting DSM-IV criteria for drug dependence.
• Meeting DSM-IV criteria for mental retardation.
• Having a history of neurological disease or head injury with loss of consciousness.