Motivation:

Biological Explanations:

Stereotypical self-mutilation has been seen in the Lesch-Nyhan, deLange, and Tourette's syndrome which has spurred interest in a biological model.

Biological Model 1:
Recent evidence suggests the role of the neurotransmitter dopamine in self-mutilation.

Biological Model 2:
In addition to dopamine, endogenous opioids have also been linked to self-mutilation. The biological reinforcement theory suggests that the pain from self-mutilation may cause the production of endorphins (endogenous opioids) that reduce dysphoria. A cycle is formed in which the habitual self-mutilator will hurt themselves in order to feel better.

Biological Model 3:
A third biological explanation suggests that individuals may mutilate themselves in order to supply sensory stimulation.

Social Explanations:

Social setting may greatly influence the onset of self-mutilation. Self-mutilation has been known to occur as an epidemic. For example, hundreds of cases of self-inflicted eye injuries have been reported among soldiers wishing to avoid duty. Furthermore, another study suggests the spread of self-mutilative behavior on the wards of psychiatric units. Self-mutilation has also been reported as a coping mechanism for inmates in repressive settings. In a Canadian correctional institution for adolescent girls, 86 percent of the inmates carved their skin. These individuals reported feeling a sense of satisfaction and control when performing self-mutilation. (Favazza)

Psychological Explanations:

Although a number of psychological theories attempt to explain self-mutilation, it is often best thought of as a purposeful act of self-help.

Pyschodynamic Theories:
Self-mutilation has been described by a number of psychodynamic theories. Some theorists suggest that self-mutilation is an attempt to differentiate between ego boundaries. Other theorists see self-mutilation as rage against the self. Self-mutilation has also been described as a mechanism to deal with sexual conflict.

Behavioral Theories:
Behavioral theories focus on the maintenance of self-mutilation rather than the cause. The positive reinforcement theory suggests that self-mutilation is maintained by positive social reinforcement. For example, some patients exhibit an increase in self-mutilation when comforting remarks are offered.
The negative reinforcement theory suggests that an individual self-mutilates in order to avoid another, more aversive stimulus. For example, a child may hit his head against the crib wall to avoid sleeping in the crib. In this situation, the head-banging behavior allows him to avoid sleeping in the crib.

Motivating factors have been linked to Major, Stereotypic, and Superficial/Moderate self-mutilation.

Cultural Explanations:

Culturally sanctioned mutilative practices are often associated with healing, spirituality, or social status. Many culturally sanctioned mutilative rituals are associated with establishment of group identity, control over sexuality, or rites of passage.