Mental illness

A mental illness or mental disorder is a psychological condition in which a person may experience behave in a somewhat inappropriate manner, be harmful to themselves or others, or find themselves obsessive or addicted to something.

One could acquire a mental illness from birth, or from trauma, whether physical or mental.

List of mental illnesses
This is a list of mental illnesses along with characters who have them.

Alcoholism

 * Question

Phobia

 * Brainiac (Mysophobia)
 * Sun Boy (Nyctophobia)

Drug Addiction

 * Roy Harper, Jr. (Heroin)
 * Hourman (Miraclo)
 * Mirror Master (cocaine)
 * Perry White (tobacco)

Obsession

 * Riddler (riddles)

Possession related mental illness
I.E. Mental instability caused by possession by a disembodied sentient or symbiote
 * Hal Jordan (Parallax)

Unknown mental illness

 * Joker