COUNTING THE WAYS.

In the 2nd century BC, Asclepiades of Bithynia distinguished between acute and chronic psychological disorders and between hallucinations and delusions. An acute episode could occur after bereavement or other loss; the depression would pass as they adjusted to their loss. A chronic condition could be permanent insanity or unremitting mood disorder.

The Roman author Aulus  Cornelius Celsus (25 BC - AD 50) provided the earliest use of the term insanity or insania in his "De medicina", written around AD30.  He distinguished between the different types by the patient's behaviour: "There are several sorts of insanity; for some among insane persons are sad, others hilarious; some are more readily controlled and rave in words only, others are rebellious and act with violence; and of these latter, some only do harm by impulse, others are artful too, and show the most coplete appearance of sanity while seizing occasion for mischief, but they are detected by the result of their act". He gave accounts of people who thought they were gods, famous figures, inanimate objects, or animals; of epilepsy and of paranoia; and distinguished between the hallucinations caused by fever and genuine delusions.

The Roman medical phylosopher Aretaeus (AD 50 - 130) recognized the pattern of bipolar disorder: periods of depression alternating with periods of mania or  excitability, with periods of lucidity in between. He campaigned for humane treatment of the mentally ill, realizing that it was not only those of limited intelligence who can have mental health problems.

In the 10th century, the Arabian physician Najir ud-din Muhammad identified 30 different types of mental illness, including agitated depression, neurosis, sexual impotence, psychosis, schizophrenia, mania, priapsm, obsesive- compulsive disorders, delusional disorders and degenerative diseases
The Swiss physician Felix Platter (1536- 1614) outlined several different types of mental disorder including mania, delirum, hallucinations, foolishness and obsessive unwelcome thoughts - an aspect of OCD, Obsessive Compulsive Disorder. (Anne Rooney, The Story of Psychology).