Schizophrenia is a chronic psychiatric illness with a heterogeneous disease course, varying from periods of symptomatic remission to relapse. Relative to the wealth of scientific data on the course of schizophrenia during the two years following the first psychotic episode, the outcome of schizophrenia patients over the first decade of their illness has been studied to a lesser degree. In this follow-up cohort study the aim is to investigate the long-term outcome of schizophrenia patients who participated in the previously conducted EULAST-I clinical trial, in the first decade after being diagnosed.

At this point, given the heterogeneity of published studies, 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 anyone 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 this study aims 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; patients will be followed up for a total of 19 months.

The primary objective of this trial is to compare all cause discontinuation rates in patients with schizophrenia randomized to oral antipsychotic medications (i.e., aripiprazole or paliperidone) versus depot antipsychotic medications (i.e., paliperidone palmitate or aripiprazole depot) over an 18 month follow-up period.

Inclusion Criteria:

1. Capable of providing written informed consent / have a legal representative to provide written informed consent. *

2. Having been randomized to one of the four treatment arms (aripiprazole oral, aripiprazole depot, paliperidone oral, paliperidone depot) in the 2014-002765-30 EULAST-I clinical trial or having participated in the EULAST-I naturalistic cohort study.

   • Unless prohibited by local law (e.g. due to incarceration).

Exclusion Criteria: No exclusion criteria are applicable in this study.

The study population will consist of patients with schizophrenia who participated in the previously conducted EULAST-I clinical trial. All patients who were randomized (to either aripiprazole oral, aripiprazole depot, paliperidone oral, paliperidone depot) or who participated in the naturalistic follow-up part of the EULAST-I clinical trial will be invited to participate in the current long-term follow-up cohort study (EULAST-II); this includes patients who dropped-out after randomization, patients who met All Cause Discontinuation (ACD) criteria and patients who completed the previous EULAST-I clinical trial. Patients will be over 18 years of age. The current long-term follow-up visit will take place at least three years after each patient's last visit as conducted within the EULAST-I clinical trial or the naturalistic follow-up study.