The goal of this study was to examine the correlates of nonsuicidal self-injury in a sample potentially at-risk for the development of a mood disorder. The prevalence of nonsuicidal self-injury in offspring of patients with mood disorders was 7.7%. We hypothesized that those with a history of nonsuicidal self-injury would be more likely to have a mood disorder and to show greater severity of mood-related symptoms and higher levels of impulsivity and aggression and to come from more adverse family backgrounds, as manifested by higher rates of physical or sexual abuse, and lower perceived care in their families. Also, as hypothesized, a family history of a suicide attempt did not predict offspring nonsuicidal self-injury, but counter to our hypothesis, nonsuicidal self-injury did not show familial transmission. We place these findings in the context of the extant literature and limitations of this study.
Consistent with previous work and the stated hypotheses, nonsuicidal self-injury was associated with a diagnosis of a DSM-IV
mood disorder as well as with greater levels of negative affect, including depressive symptoms, hopelessness, and lifetime suicidal ideation.7,16,47
The finding of increased rates of mood disorders and greater severity of mood-related symptoms in individuals with nonsuicidal self-injury is consistent with the most frequently cited function of nonsuicidal self-injury, which is to reduce tension or to interrupt negative emotional states.4,14,48
Impulsivity and impulsive aggression were additional indicators of the behavioral disturbances found with nonsuicidal self-injury, consistent with our hypotheses. Though at least 1 laboratory study found an inconclusive relationship between behavioral measures of impulsivity and nonsuicidal self-injury,49
self-reported impulsivity has a well-established association to this behavior.6,8
Impulsive aggression, defined as “a tendency to respond with hostility or aggression to frustration or provocation,”50
has been shown to aggregate in families and to serve as a predictor of suicidal behavior.20
These relationships, as well as the one found in this study between nonsuicidal self-injury and aggression, may represent an underlying tendency to behavioral manifestations of the emotional dysregulation found with this behavior11,51–53
and may help to explain the co-occurrence of nonsuicidal self-injury and suicide attempts reported here and in other studies.14,16
We hypothesized that more adverse family environment would be associated with nonsuicidal self-injury, and did find, in fact, that youths with nonsuicidal self-injury reported lower scores on the care subscale of the Parental Bonding Instrument (PBI). Higher scores on the care subscale indicate a parent-child relationship characterized by empathy and affection, while lower scores are indicative of coldness or indifference. It has been suggested that parental indifference or neglect can lead to the development of emotional dysregulation in children,51
and previous work has found lower PBI-care scores in adolescents with nonsuicidal self-injury.9
Nonsuicidal self-injury was also associated with a history of physical or sexual abuse in offspring, as per our original hypothesis. Previous work has found relationships between childhood abuse, emotional dysregulation, and nonsuicidal self-injury.1,52
One potential explanation for this finding is that physical abuse also leads to difficulty with emotion regulation and to a view of the body as an object for self-punishment. This hypothesis is consistent with one of the most frequently described functions of nonsuicidal self-injury.9,10
As hypothesized, parental suicide attempt was not associated with child nonsuicidal self-injury, supporting the view that suicide attempts and nonsuicidal self-injury are distinct behaviors. However, contrary to our hypotheses, we were not able to demonstrate that nonsuicidal self-injury ran in families.
These findings show both convergence with and divergence from previous reports examining the correlates and predictors of suicidal behavior in this sample. Both nonsuicidal self-injury and suicide attempt have been found to be associated with high levels of suicidal ideation, the diagnosis of depression, and increased impulsive aggression. However, familial characteristics, specifically parental history of suicide attempt and of sexual abuse, are much stronger correlates and predictors of suicide attempt than of nonsuicidal self-injury.18,19
Nonsuicidal self-injury, on the other hand, does not appear to display a pattern of familial transmission. Taken together, the extant findings about nonsuicidal self-injury support the view that both nonsuicidal self-injury and suicide attempt share an underlying problem with negative affect and its regulation. These commonalities may explain both their co-occurrence and the most frequently cited motivations for each behavior. Individuals with nonsuicidal self-injury often engage in the behavior in order to manage their negative affect,4,14
whereas suicide attempters may seek a permanent end to the experience of distressing emotions.53,54
However, familial characteristics play a much greater role in the development of suicide attempt; in particular, the familial transmission of suicide attempt above and beyond the transmission of mood disorder was evident,20
while no familial transmission of nonsuicidal self-injury was noted, and family history of a suicide attempt did not increase the risk for nonsuicidal self-injury.
This study has several limitations. First, the number of individuals with nonsuicidal self-injury was relatively small, precluding analyses of the relationships between clinical correlates and the severity or number of episodes of self-injury. Second, these analyses are cross-sectional and cannot provide information about the relationship of risk factors to the development of nonsuicidal self-injury over time or the longitudinal relationship between nonsuicidal self-injury and suicide attempt. Third, there are a number of domains that may assist in differentiating between these 2 behaviors, such as motivation and pain tolerance, which were not assessed in this study. And finally, the correlates of nonsuicidal self-injury found in an at-risk sample may not be generalizable to other samples, such as those found in the community.
However, this sample, one at high risk for the development of depression and self-injurious behaviors, is also a source of one of the study’s strengths. One difficulty in interpreting the literature on nonsuicidal self-injury is that the results of community and clinical studies diverge due to the differing prevalence and severity of psychopathology in the samples. This sample falls between clinical and community, as the offspring were not clinically referred but had much higher loading for psychopathology than a community sample, since all participants were the offspring of mood-disordered parents. Another strength is that precise, consistent, and widely accepted definitions of nonsuicidal self-injury and suicide attempt were used, allowing for clear differentiation between the 2 behaviors. The use of assessment by interview rather than by self-report might explain why these participants’ reported prevalence of nonsuicidal self-injury is lower than in some community studies. This is also one of the very first multigenerational studies of nonsuicidal self-injury.
In these cross-sectional analyses, nonsuicidal self-injury was most closely associated with the presence and severity of mood disorder, along with increased impulsivity and impulsive aggression and high levels of lifetime suicidal ideation. No familial transmission of nonsuicidal self-injury was evident, and a family history of suicide attempt was not related to an increased risk of nonsuicidal self-injury. On multivariate analyses, only individual-level predictors remained significant. This outcome is in contrast to previous findings in this sample, which demonstrated familial transmission of suicide attempt along with significant relationships between offspring attempt and multiple familial variables. Therefore, these 2 behaviors appear to be distinct. However, their shared diathesis of mood and behavioral dysregulation may explain why, in some studies, nonsuicidal self-injury co-occurs with and predicts suicidal behavior. These hypotheses about the interrelationships between nonsuicidal self-injury and suicide attempt will be further examined in the longitudinal follow-up of this sample.55