Project Goals

Clozapine (CLZ) is generally prescribed if at least two trials of antipsychotic agents have not led to satisfactory clinical improvement. Currently, clozapine is underprescribed worldwide.
This study focus on different groups of clozapine users. We make a distinction between new users, current users and former users. The overarching goal of the projects is to create a prediction model for clozapine outcome (response and side effects). This model includes genetic, epigenetic, and clinical data. If we know who will respond well and with no severe side-effects with an easy test, doctors might use clozapine more often. We think that this is better for patients that are in an early stage of treatment-resistant schizophrenia, but also for the more chronic patients with treatment-resistance

The main subgoals of this study are:

1. To assess whether the genetic architecture of this severe SCZ phenotype differs from the broad DSM-based SCZ phenotype.
2. To predict clozapine response and side effects based on phenotypic and genetic data obtained in this study.
3. To investigate whether methylation levels/patterns and gene expression profiles predict treatment outcome after initiating CLZ.

Patients diagnosed with schizophrenia, schizoaffective disorder or schizofreniform disorder, aged 18 years or older and have used, are using or are going to use clozapine, can enter the study.

The new users will be seen for the study once before starting CLZ, between 4 and 12 weeks after initiation on CLZ and after 6 month when patients are considered to have a steady state on CLZ. Blood will be drawn at each visit and the researcher will conduct a questionnaire which will last approximately 1 hour and 20 minutes.

The current and former users will be seen once. Blood will be drawn during this visit and the researcher will conduct a questionnaire which will last approximately 10 minutes.

Estimated enrollment:
300 new users
3700 current and former users
Study start date: January 2016
Estimated study completion date: December 2021