Self-harm (SH) or deliberate self-harm (DSH) includes self-injury (SI) and self-poisoning and is defined as the intentional, direct injuring of body tissue most often done without suicidal intentions. These terms are used in the more recent literature in an attempt to reach a more neutral terminology. The older literature, especially that which predates the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV-TR), almost exclusively refers to self-mutilation. The term is synonymous with "self-injury".The most common form of self-harm is skin-cutting but self-harm also covers a wide range of behaviors including, but not limited to, burning, scratching, banging or hitting body parts, interfering with wound healing, hair-pulling (trichotillomania) and the ingestion of toxic substances or objects.Behaviours associated with substance abuse and eating disorders are usually not considered self-harm because the resulting tissue damage is ordinarily an unintentional side effect. However, the boundaries are not always clearly defined and in some cases behaviours that usually fall outside the boundaries of self-harm may indeed represent self-harm if performed with explicit intent to cause tissue damage. Although suicide is not the intention of self-harm, the relationship between self-harm and suicide is complex, as self-harming behaviour may be potentially life-threatening. There is also an increased risk of suicide in individuals who self-harm to the extent that self-harm is found in 40–60% of suicides. However, generalising self-harmers to be suicidal is, in the majority of cases, inaccurate.
Self-harm is listed in the DSM-IV-TR as a symptom of borderline personality disorder. However patients with other diagnoses may also self-harm, including those with depression, anxiety disorders, substance abuse, eating disorders, post-traumatic stress disorder, schizophrenia, and several personality disorders. Self-harm is also apparent in high-functioning individuals who have no underlying clinical diagnosis. The motivations for self-harm vary and it may be used to fulfill a number of different functions. These functions include self-harm being used as a coping mechanism which provides temporary relief of intense feelings such as anxiety, depression, stress, emotional numbness or a sense of failure or self-loathing and other mental traits including low self-esteem or perfectionism. Self-harm is often associated with a history of trauma and abuse, including emotional and sexual abuse. There are a number of different methods that can be used to treat self-harm and which concentrate on either treating the underlying causes or on treating the behaviour itself. When self-harm is associated with depression, antidepressant drugs and treatments may be effective. Other approaches involve avoidance techniques, which focus on keeping the individual occupied with other activities, or replacing the act of self-harm with safer methods that do not lead to permanent damage.
Self-harm is most common in adolescence and young adulthood, usually first appearing between the ages of 12 and 24. Self-harm in childhood is relatively rare but the rate has been increasing since the 1980s. However, self-harm behaviour can nevertheless occur at any age, including in the elderly population. The risk of serious injury and suicide is higher in older people who self-harm. Self-harm is not limited to humans. Captive non-human animals, such as birds and monkeys, are also known to participate in self-harming behaviour.
Classification
Intentional drug abuse or overdose is a form of self-harm often committed with suicidal undertones.
Self-harm (SH), also referred to as self-injury (SI), self-inflicted violence (SIV), Non-Suicidal Self Injury (NSSI) or self-injurious behavior (SIB), refers to a spectrum of behaviors where demonstrable injury is self-inflicted. The most common form of self-harm involves cutting of the skin using a sharp object, e. g. a knife or razor blade. The term self-mutilation is also sometimes used, although this phrase evokes connotations that some find worrisome, inaccurate, or offensive. Self-inflicted wounds is a specific term associated with soldiers to describe non-lethal injuries inflicted in order to obtain early dismissal from combat. This differs from the common definition of self-harm, as damage is inflicted for a specific secondary purpose. A broader definition of self-harm might also include those who inflict harm on their bodies by means of disordered eating.
A common belief regarding self-harm is that it is an attention-seeking behavior; however, in most cases, this is inaccurate. Many self-harmers are very self-conscious of their wounds and scars and feel guilty about their behavior leading them to go to great lengths to conceal their behavior from others. They may offer alternative explanations for their injuries, or conceal their scars with clothing.Self-harm in such individuals is not associated with suicidal or para-suicidal behavior. People who self-harm are not usually seeking to end their own life; it has been suggested instead that they are using self-harm as a coping mechanism to relieve emotional pain or discomfort or as an attempt to communicate distress. Studies of individuals with developmental disabilities (such as mental retardation) have shown self-harm being dependent on environmental factors such as obtaining attention or escape from demands. Some individuals may suffer from dissociation harboring a desire to feel real or to fit in to society's rules.
Signs and symptoms
Eighty percent of self-harm involves stabbing or cutting the skin with a sharp object. However, the number of self-harm methods are only limited by an individual's inventiveness and their determination to harm themself; this includes, but is not limited to burning, self-poisoning, alcohol abuse, self-embedding of objects and forms of self-harm related to anorexia and bulimia. The locations of self-harm are often areas of the body that are easily hidden and concealed from the detection of others. As well as defining self-harm in terms of the act of damaging the body, it may be more accurate to define self-harm in terms of the intent, and the emotional distress that the person is attempting to deal with. Neither the DSM-IV-TR nor the ICD-10 provide diagnostic criteria for self-harm. It is often seen as only a symptom of an underlying disorder, though many people who self-harm would like this to be addressed. A formal proposal is currently under review (2010) to include Non-Suicidal Self-Injury as a distinct diagnosis in the forthcoming 5th edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5).
Cause
Mental illness
Although some people who self-harm do not suffer from any forms of recognised mental illness, many people experiencing various forms of mental ill-health do have a higher risk of self-harm. The key areas of illness which exhibit an increased risk include borderline personality disorder, bipolar disorder, depression, phobias, and conduct disorders. Schizophrenia may also be a contributing factor for self-harm. Those diagnosed with Schizophrenia have a high risk of suicide, which is particularly greater in younger patients as they may have an insight into the serious effects that the illness can have on their lives. Substance abuse is also considered a risk factor as are some personal characteristics such as poor problem-solving skills and impulsivity. There are parallels between self-harm and Münchausen syndrome, a psychiatric disorder in which individuals feign illness or trauma. There may be a common ground of inner distress culminating in self-directed harm in a Münchausen patient. However, a desire to deceive medical personnel in order to gain treatment and attention is more important in Münchausen's than in self-harm.
Psychological factors
Abuse during childhood is accepted as a primary social factor increasing the incidence of self-harm, as is bereavement, and troubled parental or partner relationships. Factors such as war, poverty, and unemployment may also contribute. Self-harm is frequently described as an experience of depersonalisation or a dissociative state. An estimated 30% of individuals with autism spectrum disorders engage in self-harm at some point, including eye-poking, skin-picking, hand-biting, and head-banging.
Genetics
The most distinctive characteristic of the rare genetic condition Lesch-Nyhan syndrome is self-harm and may include biting and head-banging. Genetics may contribute to the risk of developing other psychological conditions, such as anxiety or depression, which could in turn lead to self-harming behaviour. However, the link between genetics and self-harm in otherwise healthy patients is largely inconclusive.
Drugs and alcohol
Substance misuse, dependence and withdrawal are associated with self-harm. Benzodiazepine dependence as well as benzodiazepine withdrawal is associated with self-harming behaviour in young people. Alcohol is a major risk factor for self-harm. A study which analysed self-harm presentations to emergency rooms in Northern Ireland found that alcohol was a major contributing factor and involved in 63.8% of self-harm presentations. A recent study in the relation between cannabis use and deliberate self-harm (DSH) in Norway and England, found that, in general, cannabis use may not be a specific risk factor for DSH in young adolescents.
Functions of self-injury
Self-injury is considered to be a maladaptive behavior. That is, it can serve the same function as less damaging behaviors (e. g. to manage or reduce stress) but has negative health consequences (e. g. physical damage to the body) compared to other responses (e. g. meditating, taking a walk). There are many functions that self-injury can serve and they roughly fall into the broad categories of interpersonal (relating to other people) and intrapersonal (related to internal thoughts and emotions) functioning. Interpersonal influences can include nonverbal communication of desiring help from others or one’s inability to deal with a stressful situation. Intrapersonal functions can include affect regulation (i. e. regulating overwhelming emotions) and anti-dissociation (i. e. to generate feelings when experiencing emotional numbness).
Reinforcement of self-injury
Some people who have a history of self-injury have been found to have a higher threshold for physical pain. Similar to how some people have a naturally higher tolerance to alcohol and need to drink more to feel “buzzed,” this can mean that people who self-injure may need to do so more severely in order to get the same calming effect which can lead to chronicity (e. g. skin picking may escalate into finger pricking, cutting, and burning). Opponent-process theory, developed in the 1970s by Richard Solomon, gives an account of how aversive states such as physiological stress or pain can be rewarding in itself and has been proposed as an explanatory model for self-harm.
Self-injury is also thought to become chronic through operant conditioning. That is to say that it is habit forming because of its consequences. One relevant type of conditioning is positive reinforcement (i. e. additive) where a behavior becomes more frequent because of an increase in a rewarding or desirable consequence. The other relevant form of operant conditioning is through negative reinforcement (i. e. subtracting) in which the behavior decreases an undesirable event or experience. Each of the examples described above can be classified as positively or negatively reinforcing. Nonverbal communication of desiring help from others is positively reinforcing because it can elicit a response from the environment. Other times, someone may feel as though other people are being too demanding, e. g. engaging in a very long stressful conversation with a significant other. Self-injuring in this context with the intent of decreasing the demands (e. g. stopping the difficult conversation) becomes negatively reinforcing because it removes an unwanted environment condition. Someone may feel overwhelmed with their anxiety may self-injure to get rid of the anxiety.
Although the physiological mechanisms are unclear, engaging in painful behaviors can decrease arousal or emotional pain, which makes it negatively reinforcing. Someone may feel numb or as though they don’t have any emotions. This can also be very unpleasant so self-injury can make someone feel physical pain and may also stimulate an emotional response, which makes it positively reinforcing.
Pathophysiology
A flow chart of two theories of self-harm.
Self-harm is not typically suicidal behaviour, although there is the possibility that a self-inflicted injury may result in life-threatening damage. Although the person may not recognise the connection, self-harm often becomes a response to profound and overwhelming emotional pain that cannot be resolved in a more functional way.
The motivations for self-harm vary as it may be used to fulfill a number of different functions. These functions include self-harm being used as a coping mechanism which provides temporary relief of intense feelings such as anxiety, depression, stress, emotional numbness and a sense of failure or self-loathing. There is also a positive statistical correlation between self-harm and emotional abuse. Self-harm may become a means of managing and controlling pain, in contrast to the pain experienced earlier in the sufferers life of which they had no control over (e. g. through abuse).
Other motives for self-harm do not fit into medicalised models of behaviour and may seem incomprehensible to others, as demonstrated by this quotation: "My motivations for self-harming were diverse, but included examining the interior of my arms for hydraulic lines. This may sound strange."
Assessment of motives in a medical setting is usually based on precursors to the incident, circumstances and information from the patient. However, limited studies show that professional assessments tend to suggest more manipulative or punitive motives than personal assessments.
The UK ONS study reported only two motives: "to draw attention" and "because of anger". For some people harming themselves can be a means of drawing attention to the need for help and to ask for assistance in an indirect way. It may also be an attempt to affect others and to manipulate them in some way emotionally. However, those with chronic, repetitive self-harm often do not want attention and hide their scars carefully.
Many people who self-harm state that it allows them to "go away" or dissociate, separating the mind from feelings that are causing anguish. This may be achieved by tricking the mind into believing that the present suffering being felt is caused by the self-harm instead of the issues they were facing previously: the physical pain therefore acts as a distraction from the original emotional pain. To complement this theory, one can consider the need to "stop" feeling emotional pain and mental agitation. "A person may be hyper-sensitive and overwhelmed; a great many thoughts may be revolving within their mind, and they may either become triggered or could make a decision to stop the overwhelming feelings. "The sexual organs may be deliberately hurt as a way to deal with unwanted feelings of sexuality, or as a means of punishing sexual organs that may be perceived as having responded in contravention to the person's wellbeing (e. g., responses to childhood sexual abuse).
Those who engage in self-harm face the contradictory reality of harming themselves while at the same time obtaining relief from this act. It may even be hard for some to actually initiate cutting, but they often do because they know the relief that will follow. For some self-harmers this relief is primarily psychological while for others this feeling of relief comes from the beta endorphins released in the brain. Endorphins are endogenous opioids that are released in response to physical injury, act as natural painkillers, and induce pleasant feelings and would act to reduce tension and emotional distress. Many self-harmers report feeling very little to no pain while self-harming and, for some, deliberate self-harm may become a means of seeking pleasure.
Alternatively, self-harm may be a means of feeling something, even if the sensation is unpleasant and painful. Those who self-harm sometimes describe feelings of emptiness or numbness (anhedonia), and physical pain may be a relief from these feelings. "A person may be detached from himself or herself, detached from life, numb and unfeeling. They may then recognise the need to function more, or have a desire to feel real again, and a decision is made to create sensation and 'wake up'. "
As a coping mechanism, self-harm can become psychologically addictive because, to the self-harmer, it works; it enables him or her to deal with intense stress in the current moment. The patterns sometimes created by it, such as specific time intervals between acts of self-harm, can also create a behavioural pattern that can result in a wanting or craving to fulfill thoughts of self-harm.
The Autonomic Nervous System and Self-Injury
Everyone has a natural set point for their ability to experience stress. For some people this is a very high threshold whereas other people can become overwhelmed very quickly. Emotional pain activates the same regions of the brain as physical pain so this can be a very intolerable state for some people. Some of this is environmental and some of this is due to physiological differences in responding. One area of interest is the autonomic nervous system, which is composed of two components: the sympathetic nervous system controls arousal and physical activation (i. e. the fight-or-flight response) and the parasympathetic nervous system controls physical processes that are automatic (e. g. saliva production). The sympathetic nervous system innervates (i. e. is physically connected to and regulates) many parts of the body involved in stress responses. For instance, the eyes, heart, and palms are innervated. This is why when we are faced with a stressful stimulus such as a hungry lion or having to give a speech in public our pupils dilate (to take in more information), the heart rate speeds up (to pump blood to muscles needed for fight or flight), and our palms get sweaty. One common measure of sympathetic activity is skin conductance, which measures how sweaty our palms are and how well they conduct electricity. The parasympathetic nervous system controls more automatic processes such as digestion, slowing down heartbeat, and constricting bronchioles in the lungs. When faced with fearful stimuli it is important to be able to reallocate energy from automatic and non-vital processes to the fight-or-flight response. One way to measure an individual’s flexibility to do this is to measure heart rate variability with higher heart rate variability reflecting an ability to deal with stress quickly and efficiently. Studies of adolescents have shown that adolescents who self-injure have greater physiological reactivity (i. e. skin conductance) to stress than adolescent’s who don’t self-injure. Also, it is important to note that this stress response persists over time, staying constant or even increasing in self-injuring adolescents but gradually decreases in adolescents who don’t self-injure.
Prevention
The orange ribbon of self-harm awareness.
Awareness
There are many movements among the general self-harm community to make self-harm itself and treatment better known to mental health professionals as well as the general public. For example, March 1 is designated as Self-injury Awareness Day (SIAD) around the world. On this day, some people choose to be more open about their own self-harm, and awareness organisations make special efforts to raise awareness about self-harm. Some people wear an orange awareness ribbon or wristband to encourage awareness of self-harm.
Treatment
There is considerable uncertainty about which forms of psychosocial and physical treatments of patients who harm themselves are most effective and as such further clinical studies are required. Psychiatric and personality disorders are common in individuals who self-harm and as a result self-harm may be an indicator of depression and/or other psychological problems. Many people who self-harm suffer from moderate or severe clinical depression and therefore treatment with antidepressant drugs may often be effective in treating these patients. Cognitive behavioural therapy may also be used (where the resources are available) to assist those with Axis I diagnoses, such as depression, schizophrenia, and bipolar disorder. Dialectical behaviour therapy (DBT) can be very successful for those individuals exhibiting a personality disorder, and could potentially be used for those with other mental illnesses who exhibit self-harming behaviour. Diagnosis and treatment of the causes of self-harm is thought by many to be the best approach to treating self-harm. But in some cases, particularly in clients with a personality disorder, this is not very effective, so more clinicians are starting to take a DBT approach in order to reduce the behaviour itself. People who rely on habitual self-harm are sometimes psychiatrically hospitalised, based on their stability, their ability and especially their willingness to get help.
In individuals with developmental disabilities, occurrence of self-harm is often demonstrated to be related to its effects on the environment, such as obtaining attention or desired materials or escaping demands. As developmentally disabled individuals often have communication or social deficits, self-harm may be their way of obtaining these things which they are otherwise unable to obtain in a socially appropriate way (such as by asking). One approach for treating self-harm thus is to teach an alternative, appropriate response which obtains the same result as the self-harm. Additionally, the use of positive punishment apparatus such as the Self-Injurious Behavior Inhibiting System (SIBIS) can reduce the rate at which children with developmental disabilities engage in self-injurious behavior.
Avoidance techniques
Generating alternative behaviours that the sufferer can engage in instead of self-harm is one successful behavioural method that is employed to avoid self-harm. Techniques, aimed at keeping busy, may include journaling, taking a walk, participating in sports or exercise or being around friends when the sufferer has the urge to harm themselves. The removal of objects used for self-harm from easy reach is also helpful for resisting self-harming urges. The provision of a card that allows sufferers to make emergency contact with counselling services should the urge to self-harm arise may also help prevent the act of self-harm. Alternative and safer methods of self-harm that do not lead to permanent damage, for example the snapping of a rubber band on the wrist, may also help calm the urge to self-harm. Using biofeedback may help raise self-awareness in the sufferer of certain pre-occupations or particular mental state or mood that precede bouts of self-harming behaviour, and help the sufferer identify techniques to avoid those pre-occupations before they lead to self-harm. Any avoidance or coping strategy must be appropriate to the individual's motivation and reason for harming.
Epidemiology
World-map showing the disability-adjusted life year, which is a measure of each country's disease burden, for self-inflicted injuries per 100,000 inhabitants in 2004.
World-map showing the disability-adjusted life year, which is a measure of each country's disease burden, for self-inflicted injuries per 100,000 inhabitants in 2004.
In red we have more than 850 people.
It is difficult to gain an accurate picture of incidence and prevalence of self-harm. This is due in a part to a lack of sufficient numbers of dedicated research centres to provide a continuous monitoring system. However, even with sufficient resources, statistical estimates are crude since most incidences of self-harm are undisclosed to the medical profession as acts of self-harm are frequently carried out in secret, and wounds may be superficial and easily treated by the individual. Recorded figures can be based on three sources: psychiatric samples, hospital admissions and general population surveys. About 10% of admissions to medical wards in the UK are as a result of self-harm, the majority of which are drug overdoses. However, studies based only on hospital admissions may hide the larger group of self-harmers who do not need or seek hospital treatment for their injuries, instead treating themselves. Many adolescents who present to general hospitals with deliberate self-harm report previous episodes for which they did not receive medical attention.
The best available research indicates that in the United States up to 4% of adults self-harm with approximately 1% of the population engaging in chronic or severe self-harm. Current research suggests that the rates of self-harm are much higher among young people with the average age of onset between 14 and 24. The earliest reported incidents of self-harm are in children between 5 and 7 years old. In the UK in 2008 rates of self-harm in young people could be as high as 33%. In addition there appears to be an increased risk of self-harm in college students than among the general population. In a study of undergraduate students in the US, 9.8% of the students surveyed indicated that they had purposefully cut or burned themselves on at least one occasion in the past. When the definition of self-harm was expanded to include head-banging, scratching oneself, and hitting oneself along with cutting and burning, 32% of the sample said they had done this. In Ireland, a study found that instances of hospital-treated self-harm were much higher in City and Urban Districts, than in Rural settings. The CASE (Child & Adolescent Self-harm in Europe) study suggests that the life-time risk of self-injury is ~1:7 for women and ~1:25 for men.
Gender differences
In general, the latest aggregated research has found no difference in the prevalence of self-harm between men and women. This is in contrast to past research which indicated that up to four times as many females as males have direct experience of self-harm. However, caution is needed in seeing self-harm as a greater problem for females, since males may engage in different forms of self-harm (e. g. hitting themselves) which could be easier to hide or explained as the result of different circumstances. Hence, there remain widely opposing views as to whether the gender paradox is a real phenomenon, or merely the artifact of bias in data collection.
The WHO/EURO Multicentre Study of Suicide, established in 1989, demonstrated that, for each age group, the female rate of self-harm exceeded that of the males, with the highest rate among females in the 13–24 age group and the highest rate among males in the 12–34 age group. However, this discrepancy has been known to vary significantly depending upon population and methodological criteria, consistent with wide-ranging uncertainties in gathering and interpreting data regarding rates of self-harm in general. Such problems have sometimes been the focus of criticism in the context of broader psychosocial interpretation. For example, feminist author Barbara Brickman has speculated that reported gender differences in rates of self-harm are due to deliberate socially-biased methodological and sampling errors, directly blaming medical discourse for pathologising the female.
This gender discrepancy is often distorted in specific populations where rates of self-harm are inordinately high, which may have implications on the significance and interpretation of psychosocial factors other than gender. A study in 2003 found an extremely high prevalence of self-harm among 428 homeless and runaway youth (age 16 to 19) with 72% of males and 66% of females reporting a past history of self-harm. However, in 2008, a study of young people and self-harm saw the gender gap close, with 32% of young females, and 22% of young males admitting to self-harm. Studies also indicate that males who self-harm may also be at a greater risk of completing suicide.
There does not appear to be a difference in motivation for self-harm in adolescent males and females. For example, for both genders there is an incremental increase in deliberate self-harm associated with an increase in consumption of cigarettes, drugs and alcohol. Triggering factors such as low self-esteem and having friends and family members who self-harm are also common between both males and females. One limited study found that, among those young individuals who do self-harm, both genders are just as equally likely to use the method of skin-cutting. However, females who self-cut are more likely than males to explain their self-harm episode by saying that they had wanted to punish themselves. In New Zealand, more females are hospitalised for intentional self-harm than males. Females more commonly choose methods such as self-poisoning that generally are not fatal, but still serious enough to require hospitalisation.
Elderly
In a study of a district general hospital in the UK, 5.4% of all the hospital's self-harm cases were aged over 65. The male to female ratio was 2:3 although the self-harm rates for males and females over 65 in the local population were identical. Over 90% had depressive conditions, and 63% had significant physical illness. Under 10% of the patients gave a history of earlier self-harm, while both the repetition and suicide rates were very low, which could be explained by the absence of factors known to be associated with repetition, such as personality disorder and alcohol abuse. However, NICE Guidance on Self-harm in the UK suggests that older people who self-harm are at a greater risk of completing suicide, with 1 in 5 older people who self-harm going on to end their life. A study completed in Ireland showed that older Irish adults have high rates of deliberate self-harm, but comparatively low rates of suicide.
Developing world
Only recently have attempts to improve health in the developing world concentrated on not only physical illness but mental health also. Deliberate self-harm is common in the developing world. Research into self-harm in the developing world is however still very limited although an important case study is that of Sri Lanka, which is a country exhibiting a high incidence of suicide and self-poisoning with agricultural pesticides or natural poisons. Many people admitted for deliberate self-poisoning during a study by Eddleston et al. were young and few expressed a desire to die, but death was relatively common in the young in these cases. The improvement of medical management of acute poisoning in the developing world is poor and improvements are required in order to reduce mortality.
Some of the causes of deliberate self-poisoning in Sri Lankan adolescents included bereavement and harsh discipline by parents. The coping mechanisms are being spread in local communities as people are surrounded by others who have previously deliberately harmed themselves or attempted suicide. One way of reducing self-harm would be to limit access to poisons; however many cases involve pesticides or yellow oleander seeds, and the reduction of access to these agents would be difficult. Great potential for the reduction of self-harm lies in education and prevention, but limited resources in the developing world make these methods challenging.
Prison inmates
Deliberate self-harm is especially prevalent in prison populations. A proposed explanation for this is that prisons are often violent places, and prisoners who wish to avoid physical confrontations may resort to self-harm as a ruse, either to convince other prisoners that they are dangerously insane and resilient to pain or to obtain protection from the prison authorities.
Society and culture
Flagellants practiced self-flogging at the time of the Black Death
Self-harm is known to have been a regular ritual practice by cultures such as the ancient Maya civilization, in which the Maya priesthood performed auto-sacrifice by cutting and piercing their bodies in order to draw blood. A reference to the priests of Baal "cutting themselves with blades until blood flowed" can be found in the Hebrew Bible. However, in Judaism, such self-harm is forbidden under Mosaic law.
Self-harm is also practised by the sadhu or Hindu ascetic, in Catholic mortification of the flesh, in ancient Canaanite mourning rituals as described in the Ras Shamra tablets and in the Shi'ite annual ritual of self-flagellation, using chains and swords, that takes place during Ashura where the Shi'ite sect mourne the martyrdom of Imam Hussein.
In other animals
Self-harm in non-human mammals is a well-established, although not a widely-known phenomenon; its study under zoo or laboratory conditions could lead to a better understanding of self-harm in human patients. Zoo or laboratory rearing and isolation are important factors leading to increased susceptibility to self-harm in higher mammals, e. g. macaque monkeys. Lower mammals are also known to mutilate themselves under laboratory conditions after administration of drugs. For example pemoline, clonidine, amphetamine, and very high (toxic) doses of caffeine or theophylline are known to precipitate self-harm in lab animals. In dogs, canine obsessive-compulsive disorder can lead to self-inflicted injuries, for example canine lick granuloma. Captive birds are sometimes known to engage in feather-plucking, causing damage to feathers that can range from feather shredding to the removal of most or all feathers within the bird's reach, or even the mutilation of skin or muscle tissue.
