Short answers, pulled from the story.
The American Psychiatric Association defined a mental disorder as a psychological syndrome or pattern associated with distress or disability. This document explicitly excluded normal responses like grief from losing a loved one and stated that deviant behavior for political or religious reasons did not count unless it arose from an internal dysfunction.
The World Health Organization system took effect on January first, 2022. That system adopted a nearly identical definition to the DSM-5 which described a clinically significant disturbance in cognition, emotion regulation, or behavior reflecting underlying psychological, biological, or developmental processes.
Major depressive disorder accounts for 65.5 million years lost due to disability worldwide. Alcohol-use disorder contributes another 23.7 million years while schizophrenia adds 16.8 million and bipolar disorder accounts for 14.4 million.
Ancient Mesopotamian doctors kept detailed records of patient hallucinations and assigned spiritual meanings to them. They believed mental illnesses were caused by specific deities known as hands of Ishtar or Shamash.
In high-income countries, unipolar major depression causes 20% of psychiatric disabilities. Alcohol use disorder follows at 11% and suicide ranks seventh as the cause of death for women aged 20 to 59.