The study is a prospective 2 year multimodal follow-up study of initially antipsychotic-naïve first-episode psychotic patients involving a standardized intervention with monotherapy with aripiprazole during the first 6 weeks. Patients and matched healthy controls will be examined after 6 weeks, 6 months and 2 years. They will be examined with MR-scannings, neurocognitive tests, EEG, and PET-scannings.

The study is a prospective 2 year multimodal follow-up study of initially antipsychotic-naïve first-episode psychotic patients involving a standardized intervention with monotherapy with aripiprazole during the first 6 weeks. Patients and matched healthy controls will be examined at baseline and after 6 weeks, 6 months and 2 years.

Levels of glutamate and gamma-aminobutyric acid (GABA) are measured by proton magnetic resonance spectroscopy (1H-MRS) in the anterior cingulate cortex ACC and thalamus. Presynaptic Dopamine level is measured with Positron Emission Tomography Computed Tomography (PET/CT)-scanning using 3,4-dihydroxy-6-[18F]fluoro-L-phenylalanine (18F-DOPA). Disturbances of the reward system is measured with functional magnetic resonance imaging (fMRI) . Regional cerebral blood flow and activity in the same regions are measured with Pseudo-continuous arterial spin labelling (pCASL). The default mode network, functional and structural connectivity in the associated macro circuits are measured with resting state fMRI, EEG, and diffusion tensor imaging. Structural brain changes (in grey and white matter) are measured with MRI. Cognitive functions are measured with a neuropsychological test battery, and early information processing with event related EEG and electromyography (EMG) (psychophysiological examinations). Further patients psychopathology will be rated.

Inclusion Criteria Patients:

• Fulfilling the diagnostic criteria of schizophrenia or schizoaffective disorder according to ICD-10 (International Classification of Diseases version 10) or DSM-IV/V (Diagnostic and Statistical Manual version 4 /5)
• Age 18-45 years
• Never treated with antipsychotic compounds or central nervous system (CNS) stimulants
• Legally competent

Inclusion criteria controls:

• Matching patients on age (+/- 2 years), sex and parental socioeconomic status
• Age 18-45 years
• No psychiatric or physical disease

Exclusion Criteria patients:

• Substance abuse on a daily basis during the last 3 month or patients fulfilling the criteria of ongoing substance abuse due to ICD-10/DSM-IV/V
• Treatment with antidepressant during the last 30 days
• Head injury with more than 5 minutes of unconsciousness
• Patients involuntarily admitted or treated
• Components of metal implanted by operation
• Pacemaker
• Pregnancy
• Severe physical illness

Exclusion criteria controls

• First degree relatives with psychiatric disease
• Substance abuse during the last 3 month or positive screening of drugs in urine-sample
• Head injury with more than 5 minutes of unconsciousness
• Components of metal implanted by operation
• Pacemaker
• Pregnancy
• Severe physical illness