Prior suicide attempts were common in patients seeking treatment for alcohol use disorders in Poland, and the majority of these attempts were impulsive. Individuals with higher severity of alcohol use, prior sexual or physical abuse, a family history of suicidal behaviors, and self-reported impulsivity were more likely to make a suicide attempt. Those individuals with non-impulsive suicide attempts had a similar set of correlates. Of the features examined, only the behavioral measure of impulsivity could readily distinguish those with impulsive suicide attempts from those without. Thus, although impulsive suicide attempts are common in individuals with alcohol use disorders, the characteristics of those who make impulsive attempts are not well elucidated. Prevention efforts designed around more traditional sets of suicide risk factors (e.g., individuals with a family history of suicide) could potentially miss individuals at risk for an impulsive attempt.
The rates of impulsive suicide attempts in the present sample are somewhat higher than those that have been reported previously. In part, this is likely due to the use of 30 minutes to define an impulsive attempt as compared to the shorter interval of five minutes used in other research (e.g., Simon et al. and Williams et al. (Simon et al., 2001
; Williams et al., 1980
). However, Conner and colleagues (Conner et al., 2006
) defined impulsive attempts based on an interval of one week and found rates of approximately 50%. Thus, differences in the ways in which impulsive suicide attempt are operationalized do not fully explain the higher rates in this sample. It is possible that our rate of 62% reflects a more severe pattern of alcohol dependence in the present sample. In addition, this is the only study of impulsive suicide attempts in a Polish sample that we know of, so it is possible that cultural factors may have accounted for this difference.
The factors that distinguished those with and without suicide attempts were broadly consistent with similar studies of alcohol-dependent individuals. Suicide attempts were more common in those who were younger, had more severe alcohol dependence, higher rates of childhood sexual or physical abuse, higher prevalence of suicidal behaviors in a parent, and higher self-reports of impulsivity. This pattern of findings is generally consistent with what has been described previously in the literature (Hesselbrock et al., 1988
; Kingree et al., 1999
; Koller et al., 2002
; Preuss et al., 2002
; Roy, 2000
; Roy, 2001
; Roy, 2003
; Roy et al., 1990
; Swann et al., 2005
; Whitters et al., 1985
There were no differences between alcohol-dependent patients who made an impulsive and non-impulsive attempt on general scores of self-report impulsivity (Barratt Impulsiveness Scale and Impulsiveness facet of the NEO-PI-R Inventory). Moreover, when compared to individuals with no history of suicide attempts, only those with non-impulsive attempts showed higher levels of impulsiveness using self-assessment instruments. Although seemingly counterintuitive, this pattern of findings is consistent with two additional studies that failed to find higher levels of self-reported impulsivity in those with an impulsive attempt (Witte et al., 2008
; Wyder and De Leo, 2007
). The present study also included a laboratory measure of behavioral impulsivity. On this measure, individuals with a prior impulsive suicide attempt reported greater difficulty with response inhibition, suggesting a higher level of behavioral impulsiveness. These findings reinforce the idea that impulsiveness is a complex concept, which likely entails different aspects of personality and behavior (Evenden, 1999
; Reynolds et al., 2006
; Rubio et al., 2007
Previously, Simon et al. (Simon et al., 2001
) found that individuals with impulsive suicide attempts reported higher rates of aggressive behaviors than those who made a non-impulsive suicide attempt. They hypothesized that poor behavioral control was an important indicator of risk for impulsive suicide attempts. It is possible that unplanned attempts are uniquely related to a lack of behavior inhibition, but unrelated to the other aspects of impulsivity such as lack of reflection, poor planning or premeditation, or impaired attention processes.
In the present study, a subset of analyses was only possible in those who reported a suicide attempt. In these bivariate comparisons, the methods of attempt and potential lethality of these methods were similar between those with an impulsive and a non-impulsive attempt. These findings are consistent with those of Simon et al. (Simon et al., 2001
), and highlight the fact that non-planned attempts still have the significant potential to be lethal. However, a higher proportion of those with an impulsive suicide attempt reported using alcohol at the time of attempt (78%) than those with a non-impulsive attempt (52%). Others have reported that impulsive and non-impulsive attempters did not differ in their use of alcohol at the time of attempt (Conner et al., 2006
; Simon et al., 2001
; Williams et al., 1980
). However, the present findings may reflect the overall higher rate of impulsive attempts in this sample, and the high level of severity of alcohol problems at baseline.
When compared to impulsive suicide attempts, the identification of non-impulsive attempts was based on greater number of variables during multivariate analyses. The pattern of findings related to non-impulsive attempts indicates that these individuals reported many of the same factors that previously distinguished suicidal from non-suicidal individuals. In particular, compared to non-suicidal individuals, those with a non-impulsive attempt were more likely to report childhood sexual abuse, a parent who engaged in suicidal behavior, and higher trait-level measures of impulsivity. Thus, existing research on suicide and alcohol use is likely to accurately reflect a set of important risk factors for non-impulsive attempts. However, these correlates may not apply to the examination of impulsive attempts.
The results of the present study should be interpreted with caution for several reasons. First, all analyses are cross sectional and the measures of suicidal behaviors are based on self-report of lifetime suicidality. These measures are likely to be influenced by recall bias. Furthermore, no additional data are available to validate the self-report of suicidal behavior, or the length of time spent planning this behavior. Future studies of impulsive suicide attempts should measure the association between such attempts and concurrent hopelessness and/or suicidal intent using well-validated measures.
The present study did not have a strong measure for lifetime diagnosis of depression. Previous research has identified negative affect as an import factor for distinguishing between those with, and those without an impulsive attempt (e.g., Conner et al., 2006
). Self-reported history of depression did not differentiate between any of the groups of interest. The inclusion of a stronger measure for negative affect and/or depression at the time of a suicide attempt may have influenced results in regard to the multivariate models used. More broadly, future work should include structured clinical diagnostic interviews to yield more detailed data about the nature and timing of co-occurring psychiatric disorders. In addition, sample size may have impacted results, as there may have been insufficient power to detect differences between impulsive and non-impulsive suicide attempters. Finally, the extent to which the results generalize to other Polish samples, or individuals in other countries, is unknown.
Despite these limitations, to our knowledge this is the first study to compare how self-report and behavioral measures of impulsivity relate to lifetime impulsive and non-impulsive suicide attempts in individuals seeking alcohol treatment. Although impulsive suicide attempts are common, they are difficult to identify and do not necessarily fit the pattern of established risk factors for suicide. Individuals at risk for an impulsive attempt are likely to be missed by existing suicide prevention interventions aimed at those who report these more traditional characteristics. More research is needed to identify and intervene in those at risk for impulsive suicide attempts. The present findings indicate that behavioral measures of impulsivity may be one potential way to identify these individuals, and to assist in predicting future “unpredictable” impulsive attempts.