Self-mutilation has been acknowledged to be a clinically significant problem, particularly among adolescents. In this study, we found that opioid dependent cases and non-opioid dependent controls were equally likely to report self-mutilation. While previous research has suggested that opioid users are at an increased risk of suicide attempts compared to the general population (Darke & Ross, 2002
; Maloney, Degenhardt, Darke, Mattick, & Nelson, 2007
), our research highlights that self-mutilation and suicide attempts are distinct behaviors which need to be considered independently of each other.
Due to the lack of previous research in this area, it is difficult to comment further as to why no differences were identified among cases and controls in terms of self-mutilation. It is not surprising, however, that a high prevalence of self-mutilation was identified among controls (compared to general population samples) given the severe clinical profile identified among this group. A number of studies have identified an association between self-mutilation and a substance use or a psychological disorder (Cumming et al., 2006
; Evans & Lacey, 1992
; Evren & Evren, 2005
; Harned et al., 2006
; Langbehn & Pfohl, 1993
; Turell & Armsworth, 2000
; Zlotnick et al., 1999
; Zlotnick et al., 1997
); however, our findings suggest that it is not opioid dependence specifically that increases an individual's risk of self-mutilation, but the social disadvantage which can be associated with a drug dependent lifestyle. The same risk factors identified for self-mutilation are often seen at elevated levels among drug dependent individuals, which increases the risk of self-mutilation occurring.
The assessment of suicidal ideation, plans, and attempts are a routine aspect of clinical care; our findings suggest the need for self-mutilation to also be routinely assessed among individuals presenting with substance use or mental health problems. The reverse could also be suggested. If an individual discloses a history of self-mutilation it is important for clinicians to assess the possibility of co-occurring substance use or mental health disorders as these may be driving the self-harm, and could assist in the treatment of both disorders.
BPD was identified here as a unique predictor of self-mutilation. It could be argued that this association is a product of the self-harm criterion within the BPD diagnosis. When this criterion was removed from the analysis, BPD was still found to be highly predictive of self-mutilation. Other studies have found similar results after removing this criterion from the BPD diagnosis (Darke, Williamson, Ross, Teesson, & Lynskey, 2004
). Furthermore, many of the other symptom criteria within the BPD diagnosis have elements of the feelings identified within the literature as driving self-mutilation, such as escape from emotional pain and relief from unpleasant feelings (guilt, anger, loneliness, etc.) (Cumming et al., 2006
; Gratz, 2003
; Suyemoto, 1998
; Walsh & Rosen, 1988
). It has also been suggested that suicide attempts among individuals with a personality disorder and a history of self-mutilation are often viewed as manipulative and non-serious (Pattison & Kahan, 1983
; Stanley et al., 2001
); considering the high rates of completed suicide among this population (Stanley et al., 2001
) and the levels of psychological dysfunction identified in this study, this view is highly debatable.
Our findings suggest that all self-mutilation is deserving of clinical attention and that the co-occurrence of self-mutilation and suicide attempts is associated with substantial risk of comorbid psychopathology. The presence of comorbid psychiatric and substance use disorders and a history of traumatic childhood experiences greatly complicates clinical management. The need to address all of these problems, whether simultaneously or sequentially, is made more difficult since the presence of one disorder or problem may drive the occurrence of other disorders and self-harm behaviors. For example, childhood maltreatment is associated with risk for BPD, and both of these are associated with risk for poor coping and problematic adult relationships which often drive both self-mutilation and suicide attempts.
A number of limitations exist in the current study. The case and control groups were not balanced entirely in terms of age, sex, and employment status; however, these factors were controlled for statistically. The reliance on self-report and the amount of recall bias introduced in assessing lifetime prevalence could be highlighted as a limitation, yet these measures are commonly used in studies on illicit drug users and have been shown to be adequately valid and reliable (Darke, 1998
; Dougherty et al., 2004
). It has also been suggested that underreporting may exist when assessing sensitive issues such as childhood abuse, but studies have shown developmental outcomes are not affected by such underreporting (Fergusson et al., 2000
). Risk estimates obtained from opioid-dependent individuals receiving maintenance treatment are likely to be somewhat conservative versus those including individuals who are actively using opioids. The degree of psychopathology and adversity reported by our control group was surprising; the risk estimates we have presented here, may be conservative because we have overly controlled for life adversity. Because lifetime measures of psychopathology were used, it is difficult to determine whether self-harm preceded the occurrence of the risk factors assessed.