A comparison of methods of self-harm without intent to die: Cutting versus self-poisoning.

BACKGROUND: Non-suicidal self-injury (NSSI) in DSM-5 Section 3 is restricted to damaging the skin, while self-poisoning is not considered NSSI even if there was no suicidal intent. The objective of this study was to compare correlates of people who self-cut and those who self-poison without suicidal intent, to determine whether people who harm themselves by cutting are a distinct subgroup.

METHODS: There were 12,435 presentations to adult psychiatric services in the emergency departments of tertiary care hospitals in Manitoba between January 2009 and December 2013. Chart reviews were conducted for all presentations with self-harm without suicidal intent (n=219; 1.8% of the total sample). People presenting with cutting (n=47) were compared to those presenting with self-poisoning (n=116).

RESULTS: There were no differences between the groups on most demographic measures, except for age, where the people who cut were younger. Mental disorders were common in both groups. 31.9% of the cutting group had an alcohol use disorder, as did 25% of the self-poisoning group. Cluster B personality traits/disorder was diagnosed more frequently in the cutting group (51.1%) than the self-poisoning group (37.9%), but this difference was non-significant. Previous non-suicidal self-harm was more common among people cutting.

LIMITATIONS: We were unable to draw conclusions about the risk of suicide.

CONCLUSIONS: People who engage in non-suicidal self-harm have high rates of mental disorders. The method that people use to harm themselves does not appear to distinguish these groups; they appear to be similar on most demographic and diagnostic correlates. Further study is required to determine the validity of NSSI, including studies that compare those who self-harm with and without suicidal intent.