Causes
Several theories addressing the causes of self-mutilation have been championed. A few, with particular attention to impulse-control dysfunction, are described here.
Biological contributions. Support for a biological mechanism is beginning to emerge. Dysregulation in neurotransmission or neurobiological function may predispose a person to self-mutilate through the expression of impulsive traits such as motor disinhibition and a tendency to physical aggression.6 Decreased serotonergic functioning or a central deficit in serotonergic functioning—as measured by platelet imipramine binding levels and serotonin metabolites in the CSF—are seen in self-mutilators and persons with other impulsive behaviors, such as completed suicide, physical aggression, and pathologic gambling.11,12
CASE REPORT ‘PAIN FROM CUTTING MAKES ME FEEL ALIVE’
Mrs. K, age 39, is being treated for depression. She reports an onset of cutting behavior in college after she broke up with a boyfriend. She recalls being so agitated at the time that she instinctively grabbed a knife and began scraping her forearm. Since then, she has been cutting about three to four times a year and always in the context of an overwhelming stressful situation. So far, no serious medical consequences have resulted; she usually draws blood, then cleans and bandages the wound.
She is facing a divorce and is in a tumultuous battle with her estranged husband over custody of their children. As a result, her cutting behavior has increased in frequency to once or twice a week. These behaviors bother her, but she also reports that cutting allows her to “feel pain that makes me feel alive.” She denies suicidal intent. She wishes she could use another way to deal with emotional pain but finds herself yielding to cutting behaviors. Mrs. K has tried alcohol on some occasions and thought about using illicit drugs but did not know how to get them.
One of the reasons she sought treatment was to reduce her cutting behaviors. She feels that she can’t control her behavior and wants to understand why she repetitively chooses to engage in it.
Self-mutilators also respond abnormally to infusions of the adrenergic agent fenfluramine—they show decreased release of prolactin, which signals reduced serotonergic function.11,12 Reports of a blunted serotonergic response in patients who attempt suicide and in those who complete a self-mutilation act strengthen this theory of a biological contribution.12
Finally, in examining the relationship of impulsivity and serotonergic function, Herpertz found a link between trait impulsivity—as measured by a deficit in problem-solving ability and affective hyperreactivity—and low serotonergic function.6 What remains unclear, however, is cause and effect: do impulsivity traits cause serotonergic dysfunction, or do serotonin function deficits manifest as impulsivity?
Table 2
PROFILE OF PATHOLOGIC SELF-MUTILATORS
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In one fascinating study, self-mutilators whose primary diagnosis was borderline personality disorder tolerated more physical pain than did healthy controls.7 When they were tested during a distressed state of mind, self-mutilators’ pain thresholds were even more elevated. This finding suggests alterations in the opiate systems and stress-response pathways.
Further work—including genetic studies and functional neuroimaging—is needed to better understand the neurobiological locus of pathologic self-mutilation.
Psychological contributions. Self-mutilation may represent a compromise between choosing life or death. Some analysts have viewed self-mutilation as a coping mechanism to avoid suicide.1,13 In other words, self-mutilation is the expression of psychic pain turned outward but without the intent to end life. Self-mutilation may then be viewed as a way to concretely demonstrate negative affective states to the self and to the world. It also may serve as a tool to regulate and cope with these negative affective states.
Unfortunately, this coping behavior can become irresistible and psychologically tempting. One self-mutilator writes, “It’s like a relief; I do it [cutting on her wrists] every couple of weeks, just to get relief…from pressure that builds up inside…you feel like you’re going to explode if you don’t cut.”1 The described rise in tension is reminiscent of other impulse control disorders.
Hyperreactivity of decision-making also is correlated with self-mutilation, as it is with impulse-control disorders. Impulsive people tend to respond very quickly to environmental stimuli, rather than suppressing physical and emotional responses.6 One behavioral definition of impulsivity is the tendency to choose smaller, more immediate rewards instead of larger, delayed rewards. In the case report presented earlier, Mrs. K chose to cut her wrists instead of waiting for the negative affective state to pass. Waiting—which would have taken more time—would have offered the obvious benefit of avoiding physical harm.