Overview

• Researchers linked data from over 3 million Danes across national population registers and historic church archives to map family ties back to 1920.
• Findings reveal that 89% of people with schizophrenia and 60% of those with depression lack close relatives with the same disorder.
• Lifetime risk metrics indicate that 92% of individuals with an affected first-degree relative do not develop schizophrenia themselves.
• The analysis underscores mental disorders as highly polygenic conditions influenced by many small genetic variations as well as environmental factors.
• Authors recommend a dual-track approach combining individual genetic and environmental profiling with population-level interventions to reduce stress and promote mental well-being.