Uppsala Psychosis Cohort

Inclusion Criteria For EPP: * Diagnosis as assessed using DSM-5 of one of the following: schizophrenia, schizophreniform psychosis, psychosis not otherwise specified (NOS), brief psychosis, schizoaffective syndrome, delusional disorder * Onset of psychotic symptoms together with functional decline no more than 3 years prior to inclusion visit For CHR-P: Clinical high risk for psychosis as determined using Structured Interview for Psychosis-risk Syndromes (SIPS). Exclusion Criteria For EPP and CHR-P: * Other dominant psychiatric illness that is deemed to be related to current psychotic symptoms (including bipolar disorder, major depressive disorder, autism) * Long-term daily treatment (\<2 weeks) with benzodiazepines, such that there is an inability to refrain from treatment during testing procedures. For HC: * A history of diagnosis of a major psychiatric disorder, including substance use disorders. * A family history of psychotic disorders or bipolar disorder in first degree relatives. For all participants: * Evidence based on medical history, clinical signs, MRI or laboratory tests of clinically significant somatic disorder, or previous disorder with brain engagement (e.g. tumour, neuroinflammatory disease, epilepsy) or significant brain trauma. * Exposure to an effective radiation dose of 25 mSv during the past year. * Pregnancy, lactating or breastfeeding (women). * Lack of proficiency in Swedish language, or documented intellectual disability that prohibits ab…