What Most People Don't Know About Self-Harm: The Evolutionary Basis for Injury

Monday, March 02, 2015 by Meg   •   Filed under General

"I just want the pain to go away. The blade....it helps. I just don't know how else to make the feelings stop."

The woman in my office was not alone. Self-harm is an issue that is notoriously difficult to cope with, for individuals and families alike. There are several models that explain why these issues may come about, some of which have adaptive significance. Though it is unlikely that only one of these is triggering the behavior on its own, understanding them in combination may help those who engage in self-harm, those who love someone who does, and those who treat them. 

This blog is for informational purposes only. If you or someone you love is engaging in self-harm, please seek professional help and check out the books at the bottom of this post.

Intentional self-harm is generally impulsive and may include the following: 

1. Cutting self
2. Biting self
3. Burning skin
4. Breaking bones
5. Picking at skin or wounds
6. Hair pulling
7. Head-banging (more common with developmental disabilities)
8. Self surgery including castration or eye enucleation (removal of eye) These are rare and self abuse is often accompanied by psychosis

Most commonly reported reasons for self-harm:

1. To reduce unwanted emotions
2. To provide distraction from emotions, including anxiety, depression, racing/obsessive thoughts, guilt/shame, rejection, sexual preoccupation, eating disordered thoughts or activities 
3. To increase feelings of control
4. To self-punish
5. To ward off numbness/to feel something (this is common in trauma victims and in those who report lack of feelings or "emptiness".)
6. As a cry for help/to express feelings to others

At fist glance, these behaviors might seem maladaptive, regardless of the reason. But they may come about as the result of several different systems at work inside all of us.

Theories On The Cause Of Self-Harm:

Pharmacological Model: Can Chemical Imbalances Cause Self-Harm? 

Okay, so first there are the guys who think it's just about the biology as opposed to the psychology. In this case, they may be onto something. 
Though trouble with the regulation of neurotransmitters probably comes from somewhere (discussed below), there does seem to be some chemical basis for self-harm. According to researchers Winchal and Stanley out of Columbia University, those who engage in self-injury tend to have trouble regulating serotonin, dopamine and opiate systems1. These systems influence mental health issues including anxiety and depression, and over time create changes in the brain that trigger the release of additional chemicals, which lead to further brain changes in a self-sustaining cycle.

Obviously, those with chemical imbalances may feel very out of control, because in a sense they are. All emotional responses have a chemical base, and when faced with feelings triggered by internal systems, one may feel little ability to stop it. Cutting may help people to deal with those internal triggers because increases in endorphins from pain may help adjust chemical reactions.

But what leads to changes in chemical makeup in the first place?

Evolutionary Model: Belief of Hinderance to Group Fitness

There are those who believe that self-harm comes about from misreading the surrounding environment; essentially that an internal mechanism for self destruction starts if someone believes their lives are a cost rather than a benefit to their families.  This model is most relevant to cases where harming behaviors have escalated into suicidal attempts. It is critical to note that these cases are the minority and that most who harm are not trying to commit suicide. However, due to the overall belief that this is the case, we might as well talk about it and get it over with.    

Bear with me, because this one is a little dark. 

The hindrance to group fitness model sees self harm as a mechanism that would serve to weed out individuals of lower inherent worth to the group.  Essentially, the theory is that individuals who pose a burden for close kin, and have lower reproductive value, should be expected to respond with hormonal changes resulting in depression, hopelessness, suicidal thoughts or self harming behaviors2. This theory is consistant with the fact that suicidal thoughts and compulsive self injury usually occur in those with low self worth.

While these thoughts often become part of a scary thought pattern as opposed to an actual drive to commit suicide, researchers believe that those who go on to attempt suicide may be responding to this drive. In one recent study, researchers collected data about suicidal ideation and self harming behaviors along with fitness measures in order to determine how much the students thought they were costing their families. They found significant relationships between perceived cost to kin and lower reproductive value and higher rates of suicidal thoughts and behaviors2. The biggest predictor of depression and hopelessness was the belief that they were costing their families more than they were worth. 

However, this DOES NOT mean that the perceived cost and benefit was accurate.

What it does mean is that as long as individuals believe that they have less inherent worth, they may believe that their lives have less value, despite the fact that these perceptions are not based in truth. The hindrance to fitness model may be an internal system that triggers depression or self destruction based on less than ideal social cues, or the suicidal thoughts may result from the culmination of negative thought patterns, low self-worth, depression and anxiety that precede the drive to self-harm. 

However, again, this particular model seems most relevant once depression escalates into suicidal attempts. Before that, most who self harm are trying to cope with emotional pain, not attempting to extinguish life.  

The Evolutionary Cry For Help

According to prominent anthropologist Edward Hagen, self-harming behaviors may be a biologically supported cry for help. In a study focused on the biological benefits of deliberate self harm, Hagan found that this type of behavior may have served a purpose, both now and in our ancestral lineage3. The short and dirty is as follows: 

1. Due to the evolution of reasons to lie, people became more sensitive to untruths. 
2. Due to increased sensitivity to lying, individuals had to prove real need to get assistance, usually by cost to themselves. (Like a peacock growing a huge tail: He must be fit, because only a fit bird could afford the cost of growing the tail.)
3. In order to prove need for assistance, humans developed a model which expressed real need because it included real fitness costs (such as cutting or self injury).

Unlike situations of depressive suicide, Hagan argues that those engaging in self-injury show relief following such exercises, possibly related to the internal assumption that help will now be forthcoming. Particularly in those with social partners whose own fitness may depend on them, investment from other parties may increase in response to self harm. For example, a parent or a spouse has a lot riding on the health of the individual and they would be expected to respond strongly with assistance when faced with self-injurious behavior. 

The hypothetical increases in help and support that would be expected based on this model are generally what occurs today. However, it may be debatable exactly how others are weighing costs and benefits to the cutting and the helping behaviors.

Evolutionary Model: Primate Chemical Responses to Stress

According to researchers, rhesus monkeys also engage in self-harming behaviors, giving credence to some type of evolutionarily-relevant link to human self harm. This study found that risk factors in monkeys included higher numbers of painful procedures, nursery-rearing (away from mother) and higher rates of isolation4

So, pain, lack of attachment and isolation. We might be on to something. 

In the book Primate Models of Children's Health and Developmental Disabilities, Burbacher, Grant and Sackett note that in monkeys, spontaneous self-injurious behaviors arise from negative early experiences, coupled with stressful events in later life. At these junctures, individuals may experience difficulties with regulating bodily systems including neuroendicrine and neurochemical pathways5. These systems regulate serotonin, dopamine and other stress hormones (mentioned above) and are critical in controlling body responses, including the high anxiety often reported in those who self harm.

The neurochemical model is supported in other obsessive or compulsive types of disorders, such as anorexia and bulimia (discussed in future posts). Due to the high overlap between the two, some believe that they are part of the same underlying process. 

While Burbacher, Grant and Sackett note that genetic predisposition may play a role, primatologist Robert Sapolsky found that what were once thought to be genetic predispositions may actually the result of a less than ideal gestational environment6. In Why Zebras Don't Get Ulcers, Sapolsky argues that higher levels of stress hormones in mothers can lead to infants who learn to secrete extra stress hormones in preparation for life outside the womb. After all, if the world out there is scary, you better get ready for it. 

Essentially, this model builds on the initial chemical-only model by further explaining how the chemical systems come to shoot out excessive hormones in the first place, namely through stressed-out pregnant mothers followed by high levels of later stress in childhood and adulthood. Once the chemicals are too high to deal with, self injury comes in to regain control of the system.

Experiential Avoidance Model ("I don't want to feel like this anymore.")

So, animals self injure as a response to stress, to gain control of a runaway system. But lots of people are stressed and not everyone cuts. Why can't everyone deal with stress other ways? Let's check out the whole "seeking control of emotions" thing.

Many don't regulate stress well, either due to hormonal imbalances or because of early attachment experiences that did not teach them appropriate coping skills. Studies indicate that the most common trigger to self harm is some type of unwanted emotion, which leads individuals to escape it through cutting or some other type of pain7.

And make no mistake about it: the pain--and the endorphins it releases--can serve to decrease emotional response (as happened with Hannah in Famished). The sight (and perhaps smell) of blood in particular triggers a primitive defense mechanism which lowers blood pressure and corresponding anxiety symptoms. After all, if you were injured and bleeding on the savannah, it would have been in your best interest to slow your heart rate and avoid bleeding out. 

While some individuals do report that self punishment is a goal of self-harm behaviors, the majority use it as a means of stress relief, or to feel anything at all, as in cases of post-traumatic numbness. Researchers have found that the better self harm works to control emotional upset from either cause, the more likely it is to continue8

So, the relief from an unwanted emotion is the reward, and the cutting itself is merely the thing done in order to get that reward. 

We all do things we don't want to in order to accomplish an end goal, and once we find ways that work, we stick to them. This type of behavior may not be so different in terms of reward and punishments, but it is more taboo, therefore more shameful and more anxiety producing. Unfortunately, this shame response can lead to just one more set of emotions for one to try to resolve, and indeed, the guilt over the behavior is often reported as a trigger for cutting as well. 

Shame can also lead to increases in isolation, another trigger for anxiety, depression and self harm. But this solitary element of self injury provides yet another complication. Lack of socialization, in a species who evolved to be highly social, has the potential to trigger all kinds of psychological distress. As these disorders evolve, many find themselves alone more and more of the time, as they replace support with self harm to calm emotions.

So, what do we do? How can we help those who want to stop self-harm behaviors?

There continues to be a great deal of confusion in resolving this issue due to its complexity. Research indicates that even in large-scale reviews of data, it is difficult to tell which treatments are most effective in decreasing self harm behaviors9. The fact that any one model is sporadic at best--and ineffective at worst--supports a multi-faceted approach to treatment.

So what are those general categories? 

Early priming for stress responses: 

  • Chemical changes from gestational or childhood environments: Okay, we can't change that one after the fact, but it should give us pause in assessing and treating anxiety or depression in pregnant women and children.

Chemical model:

  • Blood, sweat and tears purge stress hormones, but it can be done without the blood. Physically improving the body's ability to process and eliminate these chemicals may be beneficial. In other words, get enough rest, eat right, avoid things you may be sensitive to (like caffeine), exercise and let your body try to get rid of some of those extra stress hormones. 
  • Drug treatment is a possibility to address badly battered regulation or adrenal systems as healing begins. Many need medication assistance as they learn to cope in other ways, particularly if changes in the brain make it difficult to short circuit the system. A psychiatrist who specializes in this area is beneficial.

Hindrance to group fitness/self-worth assessment:

  • Address social contributors to self-worth, particularly responses from family and partners that may be contributing to lower self-esteem. Seeking help from trusted loved ones or professionals may help if trying to decide whether some connections are severely detrimental.
  • Cognitive Behavioral Therapy may help to challenge negative thought patterns and improve self-worth.

Cry for help:

  • Psychodynamic therapies (listening therapies) may help to increase perceptions of support.
  • Identifying specific needs that one desires from others (more support, increased understanding, decreased shaming, improved signs of love or caring) can help. If possible, find ways to allow others to meet those needs.
  • Find ways to increase social support, both within families and outside. This may include family or group therapy and support groups for acceptance and camaraderie.

Need for Self-Control and Control of Emotions:

  • Finding control in other areas of life is critical. Everyone has control over something besides self-harm even if it doesn't feel like it. It is important to find out what that is for anyone seeking control.
  • Meditative or mindfulness practices promote self control and acceptance of difficult emotions. 
  • Identifying triggers to unwanted emotions is important, as is increasing coping skills for stress through cognitive behavioral therapy or relaxation techniques.
  • If necessary, decrease the severity or number of self-harm behaviors before stopping the behavior entirely. One may focus on charting the reduction of episodes or severity of harm in order to enhance feelings of accomplishment, control and mastery until other coping skills are in place. Someone who can decrease the number of times they engage in the behavior may be more likely to see that they have the control necessary to eventually stop. While this is a hot button topic in therapy circles, this reductionist approach may allow for treatment without overwhelming individuals with emotions they are still learning to deal with. Forcing immediate stopping of the harm in order to continue therapy may remove the control from the individual and contribute to the issue rather than resolving it.


  • Massage and other alternative therapies such as acupuncture, may increase social connectedness (think primate grooming) and possibly improve elimination pathways for stress hormones.

Ways to Reduce Stress and Cope With the Desire to Self Harm (Based on Reason): 

  • "I cut because I feel numb": Snapping a rubber band against the wrist, taking a cold shower, using ice in the area usually harmed or eating something spicy or sour may help.  
  • "I cut because I can't calm down": Identify things that are calming, such as reading a book, taking a hot bath, talking to a friend or listening to music. If it is difficult to calm down because you're holding things back, find ways to express yourself, like writing or drawing.  
  • "I harm because I am angry": Might as well fight or flee. Take a run, beat the shit out of a pillow or rip up cloth or paper. 

This issue is difficult, but it can be treated. It isn't easy--and it doesn't happen overnight--but individuals who self injure CAN take control and find additional ways to cope. 

Those who harm are just trying to find a way to deal with their feelings. Supporting those who injure can make a big difference, particularly if we erase the social stigma associated with self harm. 

Instead of encouraging shame, offer hope and compassion. Offer help. Stigma is for suckers.

Related Posts:


1. http://www.ncbi.nlm.nih.gov/pubmed/1847025
2. http://www.ncbi.nlm.nih.gov/pubmed/10322621
3. http://biology.unm.edu/Biology/pwatson/public_html/Selfharm.pdf
4. http://onlinelibrary.wiley.com/doi/10.1002/ajp.10075/abstract?deniedAccessCustomisedMessage=&userIsAuthenticated=false
5. http://www.amazon.com/Primate-Models-Childrens-Developmental-Disabilities/dp/0123737435
6. http://www.amazon.com/Why-Zebras-Dont-Ulcers-Third/dp/0805073698
7. http://www.sciencedirect.com/science/article/pii/S0005796705000525
8. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2723954/
9. http://www.ncbi.nlm.nih.gov/pubmed/10796818

Topic-Relevant Resources

Primate Models of Children's Health and Developmental Disabilities
Explores links between innate brain systems and current developmental issues

Why Zebras Don't Get Ulcers
Primatologist/biologist Robert Sapolsky on stress and your brain. Good stuff.

Cutting: Understanding and Overcoming Self-Mutilation
Great description of the causes of self mutilation and resources to cope with self harm (in yourself or in others).

Helping Teens Who Cut: Understanding and Ending Self-Injury
Great resource for parents trying to help children or for teens trying to stop cutting behaviors.

Freedom from Selfharm: Overcoming Self-Injury with Skills from DBT and Other Treatments
Great resource on dialectical behavioral and cognitive behavioral treatments specifically focused on alleviating self harm.

A Bright Red Scream: Self-Mutilation and the Language of Pain
Amazing insight into the nature of self harm (and what to do about it).

Dialectical Behavior Therapy for Binge Eating and Bulimia
A great guide for using DBT to challenge eating disordered behaviors and the thoughts that go with them.

Famished: An Ash Park Novel
Everyone's hungry for something. Some are more famished than others.