Non suicidal self injury (NSSI= deliberate, self-inflicted destruction of body tissue resulting in immediate damage, with- out suicidal intent, not culturally sanctioned) is a risk factor for future suicide though there is no intent to end life in NSSI.
Life time prevalence in reported studies vary widely ( 50% to 10%) among secondary school students. This meta analysis and meta regression by Swannell et al from Australia looked at various methodological factors contributing to such variations and provide a better understanding of the prevalence.
They included 128 prevalence assessments. Life time prevalence varied from 1.5% to 54.8%.NSSI was measured with 76 different tools, most common being Deliberate Self- Harm Inventory (DSHI; Gratz, 2001). Many methodological factors were identified as explaining the variance.( e.g. incentive given to participate, features of measurement tool like number of questions specifying methods & self administered questionnaire, anonymity etc). When adjusted for these factors, there was no increase in NSSI over time.( without adjustment, there was a trend of increasing prevalence over the years).
The overall pooled NSSI prevalence ( non clinical samples) was 17.2% among adolescents, 13.4% among young adults, and 5.5% among adults.
Authors provide some directions to future research. Participants need to understand the concept of NSSI. They should be provided with a check list covering all methods.Frequency and intensity data need to be captured. Most studies were conducted among university students and other samples would be of interest.
Comment: Self injury disorder (DSM5) is diagnosable after 5 NSSI incidents in one year. The fact that nearly one in five of the adolescents have resorted to inflict self injury is pointing towards the need for wider population based mental health interventions.
Summary of the article:
Prevalence of nonsuicidal self-injury in nonclinical samples: systematic review, meta-analysis and meta-regression. Swannell SV, Martin GE, Page A, Hasking P, St John NJ.
Suicide Life Threat Behav. 2014 Jun;44(3):273-303