F. The behavior does not occur exclusively during psychotic episodes, delirium, sub- stance intoxication, or substance withdrawal. In individuals with a neurodevelopmental disorder, the behavior is not part of a pattern of repetitive stereotypies. The behavior is not better explained by another mental disorder or medical condition (e.g., psychotic disorder, autism spectrum disorder. intellectual disability, Lesch-Nyhan syndrome, ste- reotypic movement disorder with seIf-injury, trichotillomania [hair-pulling disorder]. ex- coriation [skin-picking] disorder).
The essential feature of nonsuicidal self-injury is that the individual repeatedly inﬂicts shallow, yet painful injuries to the surface of his or her body. Most commonly, the purpose is to reduce negative emotions, such as tension, anxiety, and self—reproach, and / or to re- solve an interpersonal difficulty. In some cases, the injury is conceived of as a deserved self—punishment. The individual will often report an immediate sensation of relief that oc- curs during the process. When the behavior occurs frequently, it might be associated with a sense of urgency and craving, the resultant behavioral pattern resembling an addiction.
The inﬂicted wounds can become deeper and more numerous.
The injury is most often inﬂicted with a knife, needle, razor, or other sharp object. Com- mon areas for injury include the frontal area of the thighs and the dorsal side of the forearm.
A single session of injury might involve a series of superficial, parallel cuts—separated by 1 or 2 centimeters—on a visible or accessible location. The resulting cuts will often bleed and will eventually leave a characteristic pattern of scars.
Other methods used include stabbing an area, most often the upper arm, with a needle or sharp, pointed knife; inﬂicting a superficial burn with a lit cigarette end; or burning the skin by repeated rubbing with an eraser. Engagement in nonsuicidal self—injury with mul- tiple methods is associated with more severe psychopathology, including engagement in suicide attempts.
The great majority of individuals Who engage in nonsuicidal self—injury do not seek clinical attention. It is not known if this reﬂects frequency of engagement in the disorder, because accurate reporting is seen as stigmatizing, or because the behaviors are experi- enced positively by the individual who engages in them, who is unmotivated to receive treatment. Young Children might experiment with these behaviors but not experience re- lief. In such cases, youths often report that the procedure is painful or distressing and might then discontinue the practice.
Nonsuicidal self—injury most often starts in the early teen years and can continue for many years. Admission to hospital for nonsuicidal self—injury reaches a peak at 20—29 years of age and then declines. However, research that has examined age at hospitalization did not provide information on age at onset of the behavior, and prospective research is needed to outline the natural history of nonsuicidal self—injury and the factors that promote or in- hibit its course. Individuals often learn of the behavior on the recommendation or observa- tion of another. Research has shown that when an individual who engages in nonsuicidal self—injury is admitted to an inpatient unit, other individuals may begin to engage in the behavior.
Male and female prevalence rates of nonsuicidal self—injury are closer to each other than in suicidal behavior disorder, in which the female-to-male ratio is about 3:1 or 4:1.