Southern Federal University, Russia
Sam Vaknin is the author of "Malignant Self-love: Narcissism Revisited" and other books about personality disorders. His work is cited in hundreds of books and dozens of academic papers
He spent the past 6 years developing a treatment modality for Narcissistic Personality Disorder (NPD). Over the years, with volunteers, it was found to be effective with clients suffering from a major depressive episode as well.
If mental illness is culture-dependent and mostly serves as an organizing social principle - what should we make of the insanity defense (NGRI- Not Guilty by Reason of Insanity)?
A person is held not responsible for his criminal actions if s/he cannot tell right from wrong ("lacks substantial capacity either to appreciate the criminality (wrongfulness) of his conduct" - diminished capacity), did not intend to act the way he did (absent "mens rea") and/or could not control his behavior ("irresistible impulse"). These handicaps are often associated with "mental disease or defect" or "mental retardation".
Mental health professionals prefer to talk about an impairment of a "person's perception or understanding of reality". They hold a "guilty but mentally ill" verdict to be contradiction in terms. All "mentally-ill" people operate within a (usually coherent) worldview, with consistent internal logic, and rules of right and wrong (ethics). Yet, these rarely conform to the way most people perceive the world. The mentally-ill, therefore, cannot be guilty because s/he has a tenuous grasp on reality.
Yet, experience teaches us that a criminal maybe mentally ill even as s/he maintains a perfect reality test and thus is held criminally responsible (Jeffrey Dahmer comes to mind). The "perception and understanding of reality", in other words, can and does co-exist even with the severest forms of mental illness.
This makes it even more difficult to comprehend what is meant by "mental disease". If some mentally ill maintain a grasp on reality, know right from wrong, can anticipate the outcomes of their actions, are not subject to irresistible impulses (the official position of the American Psychiatric Association) - in what way do they differ from us, "normal" folks?
This is why the insanity defense often sits ill with mental health pathologies deemed socially "acceptable" and "normal" - such as religion or love.