Do antipsychotic drugs cause supersensitivity in the brain’s dopamine system?

Is this trial a fit for you?

A plain-English reading of the study's rules. Only the study team can confirm whether you qualify.

What this trial studies

This single-PET/MR imaging study investigates whether chronic antipsychotic exposure alters dopamine D2-like receptor availability in schizophrenia. It includes 140 participants: 30 healthy volunteers, 20 first-episode, drug-naive patients, and 90 pretreated patients, followed over three years. The study compares smokers and non-smokers to see if nicotine influences receptor changes. The primary goal is to understand potential receptor upregulation and its relation to relapse risk, treatment resistance, and motor side effects. It is conducted at a single center with standardized imaging and clinical assessments.

Why it matters

Who can join: the full rules

Inclusion Criteria for healthy subjects:

* Age: 18-65
* The subject is capable to understand scope and individual consequences of the clinical study.
* An informed consent is signed and personally dated by the subject. • No psychiatric disorder (DSM-5) currently, or in the medical history (ensured by a standardized psychiatric interview Mini International Neuropsychiatric Interview (M.I.N.I.)).

Inclusion Criteria for patients:

* Age: 18-65
* The criteria for schizophrenia after DSM-5 are met.
* The subject is capable to understand scope and individual consequences of the clinical study.
* For first-episode patients, no application of antipsychotic drugs in history. Other psychoactive substances (in particular antidepressants) are allowed if last application is at least three months ago and total Duration did not exceed three months. Benzodiazepines are allowed.
* For medically pretreated patients: at least one year pharmacotherapy with one of the following three substances: aripiprazole or quetiapine or risperidone. A medication break of - depending on the plasma level - two days (quetiapine) up to two weeks (aripiprazole) should be clinically defensible.
* An informed consent is signed and personally dated by the patient. For patients with legal support in addition: signature of the legal supervisor.

Exclusion criteria for patients and subjects:

* Hypersensitivity against apomorphine or a chemically similar substance or one of the components of the applied medication.
* Participation in other clinical trials during or within six months prior to this clinical study.
* Medical or psychological conditions which may endanger a proper performance of the clinical trial.
* Physical disorders which interfere according to type and severity with the planned examinations, which could influence the parameter to be investigated or could compromise the subject during the examination procedure.
* Inability to comply with the study protocol.
* Limited or completely repealed legal capacity.
* For female participants: positive pregnancy test on the day of the study inclusion or on the day of the PET/MR-measurement.
* Acute suicidality or endangerment
* Poor general condition.
* Participation in a study using ionising Radiation within the last five years.
* Alcohol abuse, alcohol dependence or addiction disease / abuse of dependence-inducing substances (excluding nicotine) in the history, additional exclusion criterion for healthy subjects: regular medication intake; within the last two weeks before PET/MR-measurement no drugs at all must be taken.

Additional exclusion criterion for patients: other than the approved axis I diagnosis according to DSM-5. An axis II diagnosis is not a criterion for exclusion

Where it's running

• Central Institute of Mental Health
  Mannheim, Baden-Wurttemberg, Germany Recruiting

Study contacts

• Principal investigator: Gerhard Gründer, Prof. Dr. — Central Institute of Mental Health, Mannheim
• Study coordinator: Gerhard Gründer, Prof. Dr.
• Email: gerhard.gruender@zi-mannheim.de
• Phone: +49621 1703-1900

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How to take part

1. Review the eligibility criteria above with your treating physician.
2. Check the official listing on ClinicalTrials.gov for the latest contact details and recruitment status.
3. Contact the study coordinator or principal investigator to ask for pre-screening. Pre-screening is free and never obligates you to enroll.