Treatment Response in Non-Affective Psychosis.

Recruitment & Eligibility

Status: Completed

Sex: Not specified

Target Recruitment: 63

Inclusion Criteria

Patients:
- First or later episode of psychosis, provided that the patient has not used
antipsychotics for at least one year and that lifetime use of antipsychotics
does not exceed 6 months.
- A rating of at least 4, corresponding to moderately ill, on the positive
symptoms item of the severity of illness part of the CGI-SCH at T0 (in case of
the common timeline, see study protocol C1 section 3.1) or T1 (in case of the
ideal timeline, see study protocol C1 section 3.1).
- Age: 18-35 years.
- Within the first 5 years after onset of the first psychotic episode.

Healthy controls:
- Age: 18-35 years.

Exclusion Criteria

General exclusion criteria patients:
- Antipsychotic use longer than 9 weeks at the moment of the PET scan.
- Current neurological disorder or history of neurological disorder (e.g.
epilepsy) or history of severe head trauma (contusio cerebri).
- Incompetent to participate in research.
- Patients who resist or oppose antipsychotic mediation.
- Primary diagnosis of bipolar disorder with psychotic features or major
depressive disorder with psychotic features at the start of non-clozapine
antipsychotic medication.
- Psychotic disorder due to another medical condition or
substance/medication-induced psychotic disorder.

General exclusion criteria healthy controls:
- Current neurological disorder or history of neurological disorder (e.g.
epilepsy) or history of severe head trauma (contusio cerebri).
- Current psychiatric disorder or history of any psychiatric disorder (DSM-5).
- First-degree relative with schizophrenia spectrum disorder (DSM-5).
- Incompetent to participate in research.

Exclusion criteria related to alcohol, soft/hard-drugs, and medicinal drugs
(patients and healthy controls):
- Lifetime history of DSM-5 diagnosis of any Substance Use Disorder (except
cannabis use disorder in sustained remission (12 months), tobacco use disorder
and alcohol use disorder).
- Participants who used cannabis on a daily basis for a period of at least two
weeks in the year before the first contact with the researcher.
- Current use of substances other than tobacco, cannabis or alcohol, such as
XTC, cocaine, amphetamine, opioids or GHB.
- Subjects with a disorder in the use of cannabis in the year before the
baseline assessment.
- Positive urine drug screen on the day of the MRI/PET scan (cannabis, cocaine,
XTC, opioids, amphetamines).
- Current or recent (less than 1 month ago) use of sleep medication (controls
only).
- Current or recent (less than 3 months ago) use of psychotropic drugs that may
influence the dopamine system (e.g. lithium, sodium valproate, and
methylphenidate) or anti-epileptic drugs that may influence the GABAergic
and/or glutamatergic systems.
The use of benzodiazepines, hypnotics and antidepressants in amounts within the
therapeutic range is allowed (patients only).

Exclusion criteria directly related to MRI and PET/CT scanning (patients and
healthy controls):
- Participation in a scientific examination where radiation was used, in the
last year.
- Contra-indications for MRI (e.g. pacemaker, claustrophobia, pregnancy).

Study & Design

Study Type: Observational invasive

Study Design: Not specified

Primary Outcome Measures

Name	Time	Method
<p>- Striatal [18F]-DOPA influx (Ki) values.<br /><br>- 1H-MRS glutamate and GABA levels in the ACC.<br /><br>- AEA and 2-AG plasma levels.<br /><br>- Responders: much or very much improved with regard to positive symptoms on<br /><br>the Degree of Change subscale of the Clinical Global Impression scale -<br /><br>Schizophrenia Version (CGI-SCH) at the first follow-up compared to the start of<br /><br>medication (for the common timeline, see section 3.1) or compared to the<br /><br>baseline assessment (for the ideal timeline, see section 3.1).<br /><br>- Non-Responders: minimally improved, not improved or worse with regard to<br /><br>positive symptoms on the CGI-SCH Degree of Change subscale at the first<br /><br>follow-up compared to the start of medication or compared to the baseline<br /><br>assessment.</p><br>

Secondary Outcome Measures

Name	Time	Method

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