Scientists conducted a large-scale global genetic study on data from more than six million people. They analyzed genetic data related to 14 psychiatric conditions. They revealed deep genetic links between these disorders, pointing to common biological roots. Rather than being isolated, mental disorders fall into five overlapping families. This explains the frequent clustering of diagnoses such as depression, anxiety, PTSD, bipolar disorder, schizophrenia, and substance use disorders. The study is changing the way mental illness is understood.