by Michael D. Anestis, M.S.
Non-suicidal self-injury (NSSI) - the intentional infliction of harm upon one's own body in the absence of suicidal intent - is a troubling phenomenon we have discussed at great length on PBB. The entirety of that discussion, however, has focused on adult and older adolescent populations. Our focus on these age groups has been a function of the available data, as NSSI is understudied in younger populations; however, a recent study published in the Journal of Early Adolescence by Lori Hilt, Matt Nock, Elizabeth Lloyd-Richardson, and Mitch Prinstein (2008) provided a glimpse into the nature of NSSI in middle-school aged adolescents. In this case, not only was the study itself strong and the topic inherently interesting and of great importance, but the authors of the study were essentially a "who's who" list of the NSSI research field, so if you find yourself interested in this topic, I would highly recommend seeking out the work of these authors to further your understanding of NSSI (see our references page for specific citations).
The authors had three central aims in this study. First, they wanted to present preliminary data on the frequency of NSSI in middle school aged children, while simultaneously examining whether these rates differ by sex, grade level, or race/ethnicity. Second, they wanted to examine to what degree NSSI co-occurs with other dysregulated behaviors (e.g., drug use, eating disordered behaviors) in this age group. Finally, they wanted to examine the manner in which NSSI related to changes in the adolescents' perceptions of their relationships with their parents. The participants in this study were 508 (51% female) middle school students initially in grades six (35%), seven (30%), and eight (35%) in a northeastern, middle-class community. The sample was predominantly (87%) white. 11 months after the initial assessment, these same students were assessed again, allowing the authors to examine changes in the participants' perceived relationship quality with their parents.
With respect to the first goal - providing preliminary data on the frequency of NSSI in middle school aged adolescents - the authors noted that the prevalence rates of NSSI in adult and older (high school) adolescent age groups, both in non-clinical and clinical samples (Briere & Gil, 1998; Darche, 1990; Klonsky et al., 2003; Lloyd-Richardson, Perrine, Dierker, & Kelley, in press; Ross & Heath, 2003).
| Non-clinical | Clinical | |
| Adults | 1-4% | 21% |
| Adolescents | 8.8-16.6% | 40-60% |
As you can see, NSSI is substantially more common in adolescent samples than it is in adult samples. As such, the importance of understanding NSSI in younger adolescents is quite clear. In total, the authors reported that 7.5% (n = 49) of the participants in this study endorsed having engaged in NSSI at some point during their lifetime. Additionally, of those who reported a lifetime history of NSSI, 36% endorsed having engaged in NSSI at least once per month. This rate is higher than the rate of adult non-clinical populations and, as such, the importance of this study is already quite clear. Hilt and colleagues (2008) also found that there were no differences between sex, grade levels, or race/ethnicity in rates of NSSI. In other words, boys were as likely as girls and all grade levels, ethnic, and racial groups were equally likely to engage in NSSI. Importantly, specific methods of NSSI were not measured and the ethnic composition of the sample was fairly homogeneous, so it is unclear if boys and girls may differ in the frequency of particular forms of NSSI and the ethnicity/racial findings must be interpreted with some caution.
With respect to the second goal - examining the degree to which NSSI co-occurs with other problematic behaviors - the authors pointed towards several studies in adult and adolescent samples linking NSSI to a variety of additional problematic behaviors, including substance use, eating disordered behaviors, and risky sexual behaviors (Favaro & Santonastaso, 2000; Gupta &Trzepacz, 1997; Putnins, 1995; Sansone & Levitt, 2002). In this study, Hilt, Nock, Lloyd-Richardson, and Prinstein (2008) found that individuals who engaged in NSSI were more likely than those who did not engage in NSSI to use hard drugs or nicotine. Additionally, although individuals who engaged in NSSI were no more likely to have engaged in sexual intercourse than were those who did not engage in NSSI, they were significantly more likely to have used drugs or consumed alcohol prior to and during sexual intercourse than were those who did not self-injure. Finally, although there were no differences in height or weight between those with and without a history of NSSI, individuals with a history of NSSI were significantly more likely to describe themselves as overweight, to report having fasted to lose weight, and to report having engaged in binge eating in the past year.
With respect to the third goal - examining the degree to which a history of NSSI relates to participants' perception of their relationships with their parents - the authors first discussed their theoretical understanding of NSSI. You will recall from our earlier discussion of Nock and Prinstein's (2004, 2005) functional model of NSSI, that data has indicated that self-injury can serve four different functions. Automatic or intrapersonal goals (within oneself) differ from social or interpersonal goals and NSSI can be positively (addition of a desired stimulus) or negatively (removal of an undesired stimulus) reinforced. In other words, NSSI can serve the functions of automatic positive reinforcement (e.g., to feel something, even if it is pain), automatic negative reinforcement (e.g., to diminish negative emotions), interpersonal positive reinforcement (e.g., to make somebody stay), or interpersonal negative reinforcement (e.g., to make somebody stop demanding something from you). Automatic functions have received the most empirical attention and have been shown to be the most common function of NSSI; however, the authors wanted to examine the interpersonal impact of NSSI by looking at the participants' perceptions of their relationships with their parents. Hilt and colleagues (2008) reported two important findings on this point. First, individuals with a history of NSSI reported a significantly poorer relationship with their parents than did individuals without a history of NSSI. Additionally, individuals with a history of NSSI reported an increase in the quality of their relationships with their fathers over the course of the 11 months between Time 1 and Time 2. Individuals without a history of NSSI reported no change in the quality of their relationships with their fathers and neither group reported any changes in the quality of their relationships with their mothers. This data thus indicate that the perceived quality of the relationship between younger adolescents and their fathers may be more event contingent and malleable than the perceived quality of the relationship between younger adolescents and their mothers. Additionally, the data indicate that one way in which NSSI might be reinforcing in this age group is through subsequent improvements in their relationships with their fathers and is thus supportive of the interpersonal functions of NSSI.
The authors noted several important limitations in their study that must be considered when interpreting the data. First, this is only one sample and, as such, the data represent a snap shot of one group of adolescents in one area of the country. Further replications in different areas of the country are needed before we can become more confident in the overall NSSI rates in middle school aged adolescents. Additionally, the authors did not assess the intended functions of NSSI in this sample. This is not a weakness, per se (in fact, two of the authors are the originators of the functional model of NSSI and they have explicitly measured functions in numerous other studies), but simply an important point to consider, as it is unclear whether any of the individuals in this sample who reported a history of NSSI engaged in such behaviors with any intention to impact their interpersonal relationships. Additionally, NSSI was measured at Time 1, but reflected an overall history of NSSI. In other words, it is possible that some of these individuals self-injured long before the study and that any subsequent improvements in their perceived relationship quality with their fathers was entirely unrelated to the behavior.
Despite these limitations, this study provides highly valuable insight into the nature of a troubling behavior in a young population. Simply assuming that a behavior does not occur in children or that it occurs at the same rates in the same manner as it does in older populations is a dangerous and likely entirely inaccurate approach. Hilt and colleagues (2008) addressed this by directly measuring NSSI in middle school aged children and testing assumptions about the nature of this behavior in such a young sample. Based on their data, it appears that middle school aged children in the community engage in NSSI more frequently than do adults, that boys are equally likely to engage in the behavior as girls, and that NSSI often co-occurs with a host of other problematic behaviors. The obvious implication from this data is that clinicians and parents need to be aware of NSSI as a possibility in middle school aged adolescents and to assess for the presence of such behaviors in order to help reduce the risk of a variety of problematic outcomes.
If you would like to learn more about non-suicidal self-injury, we recommend the following products, all of which are available through our online store:
Understanding Nonsuicidal Self-Injury: Origins, Assessment, and Treatment
Freedom from Selfharm: Overcoming Self-Injury with Skills from DBT and Other Treatments
Mike Anestis is a doctoral candidate in the clinical psychology department at Florida State University.
Subscribe in a reader
