mental illness

mental illness (countable and uncountable, plural mental illnesses)

1. (uncountable, psychiatry) The property of being mentally ill; mental disorders taken as a whole.
   • 2006, R. Keith Sawyer, Explaining Creativity: The Science of Human Innovation‎, Oxford University Press US, →ISBN, page 87:

     Such studies show that geniuses are not any more likely to suffer from mental illness than the rest of us.

2. (countable, psychiatry) A mental disorder.
   • 2002, Vikram Patel, Where There is No Psychiatrist: A Mental Health Care Manual‎, RCPsych Publications, →ISBN, page 70:

     Epilepsy is not a mental illness. It is caused by electrical changes in the brain.