Heroic Lunatics are Heroes with Mental Illness or Mental Disorder are heroes whom suffers from a disorder that mainly affect the personality and behavior of the Hero. Some Heroes with mental illness can be (but aren’t always) insane (like Buck from Ice Age, for example). The most popular mental disorders are amnesia, PTSD and depression. Examples can be;

•  Max Payne who suffers from depression.
•  Rorschach who has a Paranoid Personality Disorder. 
• Cloud Strife who suffers from PTSD and amnesia.

These characters are often Tragic, since the trait of being mentally unstable is being unable to tell right from wrong. Examples include Ryūko Matoi, Homer Simpson, Shoto Todoroki, Goku, Sinon and Joe Swanson.

Some can also be Pure Good if they have no corrupting factors and if their mental illness doesn't interfere with their moral agency and knowledge of right and wrong. Dory, Forest Gump and Melman are good examples for this.

Notes

• Not all heroes are mentally unstable when they first appear. While some are, others who were sane to begin with suffer experiences that causes their sanity to snap. The primary causes for this are prolonged abuse and humiliation. A severe-enough degree of fear can do it too, but less commonly.
• Please do not add dissociative heroes under this category as the category is a subtype of mentally ill heroes and adding both categories on the same hero at once would be redundant.
• Non-humanoid entities and angels never count, regardless of how good they can be. To them, such acts are normal or a simple spiritual/cultural function.

• Category: Mentally Ill - Villains Wiki