Impulsivity, a frequently misunderstood aspect of suicide risk, has long been considered important to the etiology and prediction of suicide. In particular, impulsivity is highlighted for its role in facilitating suicidal actions among those with suicidal ideation. Mann and colleagues1 developed a clinical model of suicidal behavior which suggests that impulsivity makes individuals “more likely to act on suicidal feelings.” Similarly, Bryan and Rudd2 state that impulsivity “may actually be a more significant indicator of suicide attempt than the presence of a specific suicide plan.”
Impulsivity has been adopted as a risk factor or warning sign for suicide. The American Association of Suicidology3 includes impulsivity as both a chronic and an acute suicide risk factor. Impulsivity is also highlighted by the American Foundation for Suicide Prevention and the Substance Abuse and Mental Health Services Administration.4,5 However, as discussed below, these widely held perceptions about impulsivity do not appear to be supported by research.
The claim that impulsivity facilitates transition from suicidal thoughts to suicide attempts suggests a clear and testable prediction: trait impulsivity should be higher among those who attempt suicide than among those who only consider suicide. However, to the surprise of many, research on the role of impulsivity has routinely failed to support this claim. For example, a 2007 study of young adults by Brezo and colleagues6 found that attempters scored no higher on the Barratt Impulsiveness Scale than patients with suicidal ideation who had never attempted suicide.
More recently, my colleagues and I examined a military population and found that while both suicide attempters and patients with suicidal ideation scored higher on a measure of impulsivity than those who had never been suicidal, impulsivity scores were equivalent between attempters and patients with suicidal ideation who had never attempted suicide.7 In other words, impulsivity was moderately elevated in anyone with a history of suicidality (thoughts or behavior), but the study failed to show any further elevation among those who acted on their ideation and progressed to suicide attempts.
On the basis of these surprising findings, we conducted a subsequent analysis using the UPPS Impulsive Behavior Scale. The UPPS developers, Whiteside and Lynam,8 suggest that impulsivity is a heterogeneous construct. They used a series of factor and psychometric analyses to identify 4 distinct impulsivity-related traits: Urgency (responding rashly to negative emotions), poor Premeditation (difficulties in foreseeing consequences of actions), poor Perseverance (tendency to give up easily), and Sensation seeking (preference for excitement and stimulation).
Using a brief version of the UPPS in a large sample of adolescents and young adults, we found that attempters and individuals with suicidal ideation exhibited equivalent scores on 3 of the dimensions (Urgency, Perseverance, and Sensation seeking) and that attempters scored only very slightly higher on the fourth (Premeditation). Taken together, the findings suggest that suicide attempters and individuals with suicidal ideation exhibit similar levels of trait impulsivity, a pattern that is contrary to clinical beliefs and guidelines.
The studies described above examined impulsivity as a personality trait that could occur at higher or lower levels within an individual. However, there is a second body of research that is also relevant to the role of impulsivity in suicide.
This research examines the impulsive nature of the suicide attempt itself. Many different definitions of attempt impulsivity have been used, including degree of forethought, amount of time between the decision to choose suicide and the actual suicide attempt, time spent contemplating the attempt before making the attempt, presence of a suicide plan, and amount of time spent making a plan, among many others. Given the many ways to define or identify an impulsive attempt, it is not surprising that studies on attempt impulsivity produce widely divergent results. For example, the percentage of suicide attempts estimated to be impulsive has ranged from a low of 20% to a high of 85%.9,10
Dr Klonsky is Associate Professor and Ms May is a Doctoral Candidate in the department of psychology at the University of British Columbia in Vancouver. The authors report no conflicts of interest concerning the subject matter of this article.
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