Participants

The main inclusion criteria were having a Diagnostic and Statistical Manual of Mental Disorders-IV (DSM-IV) diagnosis of SCZ spectrum disorders or bipolar spectrum disorders, intelligence quotient > 70, and age between 18 and 65 years (for details see ref. ²⁸). Healthy volunteers without any history of severe psychiatric disorders (or in any of their first-degree relatives) or substance/alcohol abuse/dependency from the same catchment area were randomly selected from the National Population Registry (www.ssb.no). For the present analyses, patients and controls were not included if they had coexisting autoimmune or inflammatory disease, cancer, ongoing infections, used anti-inflammatory drugs, or had C-reactive protein levels above 20 mg/L. In total, 1625 participants included in the study had available plasma for protein assessment. Of these, 1436 participants (551 SCZ, 246 BD, and 639 HCs) met criteria for inclusion. A subsample of patients and controls (338 SCZ, 241 BD, and 263 HC participants) had available blood samples and passed quality control for microarray analyses.