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Etiology of self injury
© Deb Martinson
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 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
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.
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. This in turn can
lead 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.
Serotonin
Coccaro and colleagues have done much to advance the hypothesis that a
deficit in the serotonin system is implicated in self-injurious
behavior. They found (1997c) that irritability is the core behavioral
correlate of serotonin function, and the exact type of aggressive
behavior shown in response to irritation seems to be dependent on
levels of serotonin -- if they are normal, irritability may be
expressed by screaming, throwing things, etc. If serotonin levels are
low, aggression increases and responses to irritation escalate into
self-injury, suicide, and/or attacks on others.
Simeon et al. (1992) found that self-injurious behavior was
significantly negatively correlated with number of platelet imipramine
binding sites (self-injurers have fewer platelet imipramine binding
sites, a level of serotonin activity) and note that this "may reflect
central serotonergic dysfunction with reduced presynaptic serotonin
release. . . . Serotonergic dysfunction may facilitate
self-mutilation."
When these results are considered in light of work such as that by
Stoff et al. (1987) and Birmaher et al. (1990), which links reduced
numbers of platelet imipramine binding sites to impulsivity and
aggression, it appears that the most appropriate classification for
self-injurious behavior might be as an impulse-control disorder
similar to trichotillomania, kleptomania, or compulsive gambling.
When these results are considered in light of work such as that by
Stoff et al. (1987) and Birmaher et al. (1990), which links reduced
numbers of platelet imipramine binding sites to impulsivity and
aggression, it appears that the most appropriate classification for
self-injurious behavior might be as an impulse-control disorder
similar to trichotillomania, kleptomania, or compulsive gambling.
It is not clear whether these abnormalities are caused by the
trauma/abuse/invalidating experiences or whether some individuals
with these kinds of brain abnormalities have traumatic life
experiences that prevent their learning effective ways to cope with
distress and that cause them to feel they have little control over
what happens in their lives and subsequently resort to self-injury as
a way of coping.
Knowing when to stop - pain doesn't seem to be a factor
Most of those who self-mutilate can't quite explain it, but
they know when to stop a session. After a certain amount of injury,
the need is somehow satisfied and the abuser feels peaceful, calm,
soothed. Only 10% of respondents to Conterio and Favazza's 1986 survey
reported feeling "great pain"; 23 percent reported moderate pain and
67% reported feeling little or no pain at all. Naloxone, a drug that
reverses the effects of opiods (including endorphins, the body's
natural painkillers), was given to self-mutilators in one study but
did not prove effective (see Richardson and Zaleski, 1986). These
findings are intriguing in light of Haines et al. (1995), a study that
found that reduction of psychophysiological tension may be the primary
purpose of self-injury. It may be that when a certain level of
physiological calm is reached, the self-injurer no longer feels an
urgent need to inflict harm on his/her body. The lack of pain may be
due to dissociation in some self-injurers, and to the way in which
self-injury serves as a focusing behavior for others.
Behavioralist explanations
NOTE: most of this applies mainly to stereotypical self-injury, such
as that seen in retarded and autistic clients.
Much work has been done in behavioral psychology in an attempt to
explain the etiology of self-injurious behavior. In a 1990 review,
Belfiore and Dattilio examine three possible explanations. They quote
Phillips and Muzaffer (1961) in describing self-injury as "measures
carried out by an individual upon him/herself which tend to 'cut off,
to remove, to maim, to destroy, to render imperfect' some part of the
body." This study also found that frequency of self-injury was higher
in females but severity tended to be more extreme in males. Belfiore
and Dattilio also point out that the terms "self-injury" and
"self-mutilation" are deceiving; the description given above does not
speak to the intent of the behavior.
Operant Conditioning
It should be noted that explanations involving operant conditioning
are generally more useful when dealing with stereotypic self-injury
and less useful with episodic/repetitive behavior.
Two paradigms are put forth by those who wish to explain self-injury
in terms of operant conditioning. One is that individuals who
self-injure are positively reinforced by getting attention and thus
tend to repeat the self-harming acts. Another implication of this
theory is that the sensory stimulation associated with self-harm could
serve as a positive reinforcer and thus a stimulus for further
self-abuse.
The other posits that individuals self-injure in order to remove
some aversive stimulus or unpleasant condition (emotional, physical,
whatever). This negative reinforcement paradigm is supported by
research showing that intensity of self-injury can be increased by
increasing the "demand" of a situation. In effect, self-harm is a
way to escape otherwise intolerable emotional pain.
Sensory Contingencies
One hypothesis long held has been that self-injurers are attempting
to mediate levels of sensory arousal. Self-injury can increase
sensory arousal (many respondents to the internet survey said it
made them feel more real) or decrease it by masking sensory input
that is even more distressing than the self-harm. This seems related
to what Haines and Williams (1997) found: self-injury provides a quick
and dramatic release of physiological tension/arousal. Cataldo and
Harris (1982) concluded that theories of arousal, though satisfying in
their parsimony, need to take into consideration biological bases
of these factors.
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