Etiology (history and causes)

Past trauma/invalidation as an antecedent
Van der Kolk, Perry, and Herman (1991) conducted a study of patients who exhibited cutting behavior and suicidality. They found that exposure to physical abuse or sexual abuse, physical or emotional neglect, and chaotic family conditions during childhood, latency and adolescence were reliable predictors of the amount and severity of cutting. The earlier the abuse began, the more likely the subjects were to cut and the more severe their cutting was. Sexual abuse victims were most likely of all to cut. They summarize, ...

neglect [was] the most powerful predictor of self-destructive behavior. This implies that although childhood trauma contributes heavily to the initiation of self-destructive behavior, lack of secure attachments maintains it. Those ... who could not remember feeling special or loved by anyone as children were least able to ...control their self-destructive behavior.

In this same paper, van der Kolk et al. note that dissociation and frequency of dissociative experiences appear to be related to the presence of self-injurious behavior. Dissociation in adulthood has also been positively linked to abuse, neglect, or trauma as a child.

More support for the theory that physical or sexual abuse or trauma is an important antecedent to this behavior comes from a 1989 article in the American Journal of Psychiatry. Greenspan and Samuel present three cases in which women who seemed to have no prior psychopathology presented as self-cutters following a traumatic rape.

Invalidation independent of abuse
Although sexual and physical abuse and neglect can seemingly precipitate self-injurious behavior, the converse does not hold: many of those who hurt themselves have suffered no childhood abuse. A 1994 study by Zweig-Frank et al. showed no relationship at all between abuse, dissociation, and self-injury among patients diagnosed with borderline personality disorder. A followup study by Brodsky, et al. (1995) also showed that abuse as a child is not a marker for dissociation and self-injury as an adult. Because of these and other studies as well as personal observations, it's become obvious to me that there is some basic characteristic present in people who self-injure that is not present in those who don't, and that the factor is something more subtle than abuse as a child. Reading Linehan's work provides a good idea of what the factor is.

Linehan (1993a) talks about people who SI having grown up in "invalidating environments." While an abusive home certainly qualifies as invalidating, so do other, "normal," situations. She says:

An invalidating environment is one in which communication of private experiences is met by erratic, inappropriate, or extreme responses. In other words, the expression of private experiences is not validated; instead it is often punished and/or trivialized. the experience of painful emotions [is] disregarded. The individual's interpretations of her own behavior, including the experience of the intents and motivations of the behavior, are dismissed...

Invalidation has two primary characteristics. First, it tells the individual that she is wrong in both her description and her analyses of her own experiences, particularly in her views of what is causing her own emotions, beliefs, and actions. Second, it attributes her experiences to socially unacceptable characteristics or personality traits.

This invalidation can take many forms:

• "You're angry but you just won't admit it."
• "You say no but you mean yes, i know."
• "You really did do (something you in truth hadn't). Stop lying."
• "You're being hypersensitive."
• "You're just lazy." "
• I won't let you manipulate me like that."
• "Cheer up. Snap out of it. You can get over this."
• "If you'd just look on the bright side and stop being a pessimist..."
• "You're just not trying hard enough."
• "I'll give you something to cry about!"

Everyone experiences invalidations like these at some time or another, but for people brought up in invalidating environments, these messages are constantly received. Parents may mean well but be too uncomfortable with negative emotion to allow their children to express it, and the result is unintentional invalidation. Chronic invalidation can lead to almost subconscious self-invalidation and self-distrust, and to the "I never mattered" feelings van der Kolk et al. describe.

Biological Considerations and Neurochemistry
It has been demonstrated (Carlson, 1986) that reduced levels of serotonin lead to increased aggressive behavior in mice. In this study, serotonin inhibitors produced increased aggression and serotonin exciters decreased aggression in mice. Since serotonin levels have also been linked to depression, and depression has been positively identified as one of the long-term consequences of childhood physical abuse (Malinosky-Rummell and Hansen, 1993), this could explain why self-injurious behaviors are seen more frequently among those abused as children than among the general population (Malinosky-Rummel and Hansen, 1993). Apparently, the most promising line of investigation in this area is the hypothesis that self-harm may result from decreases in necessary brain neurotransmitters.

This view is supported by evidence presented in Winchel and Stanley (1991) that although the opiate and dopaminergic systems don't seem to be implicated in self-harm, the serotonin system does. Drugs that are serotonin precursors or that block the reuptake of serotonin (thus making more available to the brain) seem to have some effect on self-harming behavior. Winchel and Staley hypothesize a relationship between this fact and the clinical similarities between obsessive- compulsive disorder (known to be helped by serotonin-enhancing drugs) and self-injuring behavior. They also note that some mood-stabilizing drugs (such as Tegretol, Depakote) can stabilize this sort of behavior.