It is often seen as only a symptom of an underlying disorder, though many people who self-harm would like this to be addressed. Common signs that a person may be engaging in self-harm include the following: they ensure that there are always harmful objects close by, they are experiencing difficulties in their personal relationships, their behavior becomes unpredictable, they question their worth and identity, they make statements that display helplessness and hopelessness. Cause
Mental disorder
Although some people who self-harm do not have any form of recognized mental disorder, many people experiencing various forms of mental illnesses do have a higher risk of self-harm. The key areas of disorder which exhibit an increased risk include autism spectrum disorders, borderline personality disorder, dissociative disorders, bipolar disorder, depression, phobias, and conduct disorders. As many as 70% of individuals with borderline personality disorder engage in self-harm. An estimated 30% of individuals with autism spectrum disorders engage in self-harm at some point, including eye-poking, skin-picking, hand-biting, and head-banging. Schizophrenia may also be a contributing factor for self-harm. Those diagnosed with schizophrenia have a high risk of suicide, which is particularly greater in younger patients as they may not have an insight into the serious effects that the disorder can have on their lives. There are parallels between self-harm and Münchausen syndrome, a psychiatric disorder in which individuals feign illness or trauma. There may be a common ground of inner distress culminating in self-directed harm in a Münchausen patient.
Kikuyu girls cut each others vulvas in the 1950s as a symbol of defiance, in the context of the campaign against female genital mutilation in colonial Kenya. The movement came to be known as Ngaitana ("I will circumcise myself"), because to avoid naming their friends the girls said they had cut themselves. Historian Lynn Thomas described the episode as significant in the history of FGM because it made clear that its victims were also its perpetrators. Classification
The term "self-mutilation" occurred in a study by L. E. Emerson in 1913 where he considered self-cutting a symbolic substitution for masturbation. The term reappeared in an article in 1935 and a book in 1938 when Karl Menninger refined his conceptual definitions of self-mutilation. His study on self-destructiveness differentiated between suicidal behaviors and self-mutilation. For Menninger, self-mutilation was a non-fatal expression of an attenuated death wish and thus coined the term partial suicide. He began a classification system of six types:

neurotic – nail-biters, pickers, extreme hair removal and unnecessary cosmetic surgery. religious – self-flagellants and others. puberty rites – hymen removal, circumcision or clitoral alteration. psychotic – eye or ear removal, genital self-mutilation and extreme amputation
organic brain diseases – which allow repetitive head-banging, hand-biting, finger-fracturing or eye removal. conventional – nail-clipping, trimming of hair and shaving beards.Pao (1969) differentiated between delicate (low lethality) and coarse (high lethality) self-mutilators who cut. The "delicate" cutters were young, multiple episodic of superficial cuts and generally had borderline personality disorder diagnosis. The "coarse" cutters were older and generally psychotic.