i'm currently a medical assistant student at western career college and was looking for it in one of my books. my play sister suffered from it several months ago.

It takes a physician, usually a psychiatrist to determine what causes a breakdown. it might have been triggered by depression, manic depressive illness, schizophrenia or any number of physical or mental disorder.( mental illness)

SiGNS:
Depression- Characteristic abnormalities or unusual characteristic. For example, sudden anger without reason.

Manic depressive illness- alternate or changing moods . For example, sudden irritation. less need of sleep, hyperactive, speaks rapidly, delusion, and may have sequences ideas that are impossible to follow. she can moved from manic phase to depression.

Schizophrenia- Sign if she has trouble finding the right words to express her ideas( continuous), she may show emotions that are totally inappropriate or her emotion may be blunted rather than extreme, she may laugh sad events, her behavior is bizarre.

By the way nervous breakdown is a commonly used term for various forms of mental illness.

Fidgeting, staring into space, withdrawn, unkempt, detatched, moody.