by Michael D. Anestis, M.S.
Self-injury, with or without suicidal intent, is a distressing phenomenon. Fortunately, if you or somebody you know struggles with such thoughts and behaviors, you have many effective resources available to help. We have discussed empirically supported treatments such as dialectical behavior therapy (DBT) in the past and I highly recommend that you consider reading those articles to learn more about treatments that have been shown in scientific studies to reduce the frequency and severity of self-injurious behaviors. In addition to what we have learned about therapeutic techniques that work, a mountain of research has been conducted to help us understand why people engage in these behaviors in the first place and, if you would like to learn more about this side of things, I hope you will consider reading further.
In prior PBB articles, we have discussed Matt Nock and Mitch Prinstein's (2004, 2005) functional model of non-suicidal self-injury (NSSI). Today, I would like to discuss a study published in Behaviour Research and Therapy by Sadia Najmi, Daniel Wegner, and Matt Nock (2007) of Harvard University in which the authors examined the relationship between thought suppression and self-injurious thoughts and behaviors (SITB), including NSSI, suicidal ideation, and suicide attempts. In this study, as you will see, Najmi and colleagues illustrated why certain individuals prone to high emotional reactivity frequently decide to engage in SITB.
If you read our earlier articles on the functional model, you might remember that the authors proposed individuals engage in NSSI for four reasons:
- Intrapersonal negative reinforcement (to reduce negative emotions)
- Intrapersonal positive reinforcement (to feel something, even if it is pain)
- Interpersonal negative reinforcement (to reduce or remove expectations of others)
- Interpersonal positive reinforcement (to cause another individual to feel something or behave in a particular manner)
Data indicates that intrapersonal negative reinforcement is the most common function of NSSI - a point that contradicts the harmful myth that self-injury is generally an attempt to manipulate others. In the Najmi et al (2007) study, the authors wanted to take a closer look at this phenomenon in an effort to help elucidate how individuals end up making the decision to self-injure. Their investigation centered on the idea of thought suppression - defined as an intentional effort to avoid thinking about a particular topic - which is a cognitive strategy often utilized by individuals seeking to regulate negative emotions (Wegner, 1989). Najmi and colleagues (2007) focused on thought suppression because research has shown it to be unsustainable when an individual is faced with multiple cognitive demands and, perhaps even more importantly, has demonstrated that after thought suppression efforts end, unwanted thoughts tend to re-emerge with even greater intensity. In other words, thought suppression is typically a counterproductive activity.
Thought suppression is not always unsuccessful, however. Najmi et al (2007) pointed out that generally speaking, thought suppression is most likely to fail when an individual attempts to suppress thoughts by focusing on a variety of different distracters (Wegner, Schneider, Knutson, & McMahon, 1991). When a focused distracter is used, meaning thought suppression is achieved through deliberate focus on one particular stimulus or activity, an individual is more likely to be successful in reducing his or her negative emotions. Unfortunately, however, some individuals turn to SITB as their focused distracter and this is where the authors focused their attention in this particular study. The authors' vision of the path to SITB was as follows:
Certain individuals are highly reactive to emotional stimuli and, as a result, experience more frequent unpleasant thoughts and emotions. These individuals are motivated to use some form of coping mechanism to change what they are thinking and feeling and, for some, thought suppression is a commonly used tool. Unfortunately, some of the individuals who turn to thought suppression use SITB as their focused distracter, thereby enabling them to achieve immediate and reinforcing reductions in negative emotions and an escape from unwanted thoughts but also causing them to experience the negative long term consequences of frequent SITB.
The authors hypothesized that the tendency to suppress unwanted thoughts would predict a higher frequency and range of SITB. Additionally, they anticipated that thought suppression would partially statistically explain (mediate) the relationship between emotional reactivity and SITB. Finally, Najmi et al (2007) hypothesized that individuals who engage in thought suppression would be more likely to engage in NSSI in an effort to reduce negative emotions (intrapersonal negative reinforcement) than to communicate with others (interpersonal positive reinforcement).
To test these hypotheses, the authors utilized a sample of 94 adolescents and young adults who were recruited both from the community and from local psychiatric clinics. Participants were administered a series of self-report questionnaires as well as the self-injurious thoughts and behaviors interview (SITBI; Nock, Holmberg, Photos, & Michel, 2006). The sample and methodology in this study were both extremely strong and the findings were very compelling.
Najmi et al (2007) found that the tendency to engage in thought suppression predicted the presence and frequency of NSSI, suicidal ideation, and suicide attempts. In other words, people who attempt to suppress their thoughts are more likely to self-injure with or without suicidal intent and to think about suicide. Additionally, the authors found that thought suppression mediated the link between emotional reactivity and SITB. In other words, the authors were able to show that being highly emotional is related to self-injurious thoughts and behaviors in part because high levels of emotional reactivity leads to thought suppression, which in turn directly influences the decision to engage in SITB. Finally, the authors found that individuals who engage in thought suppression are significantly more likely to use NSSI in an effort to reduce negative emotions than to manipulate others.
For a number of reasons, these findings are extremely important. First of all, as anyone who has been told to simply stop thinking about something upsetting can attest, doing so rarely works. These data provide objective evidence that attempting to suppress thoughts not only does not work, but in fact predicts horrific behavioral and cognitive consequences. As such, the utility of therapeutic interventions like cognitive behavioral therapy (CBT) that focus on challenging and altering thoughts rather than simply avoiding them, is quite clear. These findings are also important because they help us to understand why being highly emotional is linked to SITB. Simply knowing that those two variables are related to one another does not help us address the problem, but an understanding of why the connection is there helps us target harmful mechanisms of action and effectively reduce the frequency of the unwanted behavior. Finally, these findings are important because they yet again shine a light on the fact that individuals who self-injure are rarely doing so to manipulate others. As aversive as it is for us when somebody we know self-injures, far more often than not, it is worse for them and they are doing it because they are struggling to regulate their own emotions, not because they want to harm or manipulate us. Manipulation certainly occurs, but it is not the norm.
If you would like to learn more about non-suicidal self-injury, suicide, or empirically supported treatments aimed at addressing these outcomes, we recommend the following resources, all of which are available through our online store:
- Understanding Nonsuicidal Self-Injury: Origins, Assessment, and Treatment
by Matt Nock
- Why People Die by Suicide
by Thomas Joiner
- Treating Suicidal Behavior: An Effective, Time-Limited Approach
by David Rudd, Thomas Joiner, and Hasan Rajab
- The Interpersonal Theory of Suicide: Guidance for Working With Suicidal Clients
by Thomas Joiner, Kim Van Orden, Tracy Witte, and David Rudd.
- Cognitive-Behavioral Treatment of Borderline Personality Disorder
by Marsha Linehan
- Skills Training Manual for Treating Borderline Personality Disorder
by Marsha Linehan
Mike Anestis is a doctoral candidate in the clinical psychology department at Florida State University.
