Synaptic dysfunction is increasingly recognized as a core feature of psychiatric disorders, yet fluid biomarkers that reflect such changes in vivo are lacking. Here, we applied targeted mass spectrometry to quantify low-abundant synaptic proteins in cerebrospinal fluid from 672 individuals with anorexia nervosa, attention-deficit/hyperactivity disorder (ADHD), bipolar disorder (BD), schizophrenia spectrum disorders (SCZ + ), and healthy controls. Synaptic protein levels were markedly reduced in…
