رفتار خودآسیبی در میان افراد مبتلا به اختلال انفجاری متناوب و اختلالات شخصیت

Abstract Self-harm behaviors are a major public health concern across the lifespan, particularly among individuals with psychiatric disorders. Little research, however, has examined these behaviors among individuals with a diagnosis characterized by recurrent acts of impulsive aggression, Intermittent Explosive Disorder (IED). Furthermore, extant research has not examined variables that might mediate the relationship between IED and self-harm. The current study examined the rates of non-suicidal self-injury (NSSI) and suicide attempts among individuals with IED as compared to healthy controls, individuals with personality disorders (PDs; which are highly comorbid with IED), and individuals with comorbid IED and PD. The study also examined the indirect effects of aggression, impulsivity, and affective lability in the relationship between diagnosis and self-harm. Participants were 1079 community individuals and prevalence rates among the total sample were 18% for NSSI and 13.2% for suicide attempts. Scores on measures aggression, impulsivity, and affect lability showed significant indirect effects on the relationships between IED + PD and NSSI; scores on aggression showed a significant indirect effect on the relationship between PD and NSSI; scores on impulsivity showed a significant indirect effect on the relationship between IED + PD and suicide attempt. These results suggest that individuals with PDs, and particularly those with comorbid IED and PD, are at increased risk for engagement in self-harm behaviors. Furthermore, traits of aggression, impulsivity, and affect lability significantly accounted for the relationship between diagnostic status and self-harm, particularly in regards to NSSI.

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3. Results 3.1. Preliminary analyses Pearson correlations between self-report measures of aggression (BPAQ), impulsivity (BIS), and affect lability (ALS) were all significant (see Table 1). Comorbid psychopathology and demographic variables differed as a function of diagnostic group (see Table 2). Diagnostic groups differed with respect to both race [χ2(6) = 70.79, p < .001] and education [χ2(3) = 26.82, p < .001]. All three clinical groups had a higher proportion of African Americans to Caucasians than the Control group, with the IED + PD group also having a higher proportion of African Americans to Caucasians than the other clinical groups. The IED and IED + PD groups were also less likely to be college educated than the PD or Control groups. Age also differed as a function of diagnostic group [F(3,1076) = 4.42, p = .004], with the individuals in the IED + PD group being older than those in the Control group. Table 1. Pearson correlations between study self-report measures. 1 2 3 1. Affect Lability Scale – 2. Barratt Impulsivity Scale .54** – 3. Buss Perry Aggression Questionnaire .57** .50** – Note. **p < .01. Table options Table 2. Demographic and study variables as a function of diagnostic group. Control IED only PD only IED + PD % Female 54.4% 58.1% 52.8% 58.1% Race % Caucasian 72.1% 64.9%a 62.5%a 45.8%a,b,c % African-American 12.7% 23.0%a 24.5%a 25.3%a,b,c % Other 15.2% 12.1% 13.0% 18.4%b,c Level of education % No college 8.4% 21.9%a,c 9.9% 19.6%a,c Mean age (SD) 33.92 (10.51) 35.88 (10.12) 34.16 (9.62) 36.31 (10.33)a Psychopathology Major Depressive Disorder 0% 32.4%a 43.5%a 49.3%a,b,c Any other Mood Disorder 0% 5.4%a 9.3%a 15.9%a,b,c Any Anxiety Disorder 0% 16.2%a 42.1%a,b 42.2%a,b Any Substance Use Disorder 0% 36.5%a 36.1%a 48.9%a,b,c Any Eating Disorder 0% 1.4% 10.6%a,b 12.2%a,b Cluster A PD 0% 0% 6.5%a 17.0%a,c Borderline PD 0% 0% 9.7%a 36.5%a,c Any other Cluster B PD 0% 0% 10.6%a 33.8%a,c Cluster C PD 0% 0% 41.7%a 26.8%a,c Associated variables Aggression (BPAQ) 56.30 (17.01) 69.57 (17.62)a 69.41 (17.56)a 92.28 (23.36)a,b,c Impulsivity (BIS) 57.17 (9.13) 62.98 (9.84)a 64.45 (10.01)a 69.13 (11.09)a,b,c Affect Lability (ALS) 73.32 (21.11) 86.43 (27.85)a,c 101.97 (29.10)a,b 121.18 (30.94)a,b,c Note. IED = intermittent explosive disorder; PD = personality disorder; IED + PD = comorbid intermittent explosive disorder and personality disorder; BPAQ = Buss Perry Aggression Questionnaire, BIS = Barratt Impulsivity Scale, ALS = Affect Lability Scale. a Significantly different from Controls. b Significantly different from the IED group. c Significantly different from PD group; all p-values <.05. Table options Among the three clinical groups, there were significant differences in the lifetime prevalence of several types of psychopathology, including major depressive disorder, any other mood disorder, any anxiety disorder, any eating disorder, and any substance use disorder [χ2(2) = 7.82–31.72, all p < .02] (see Table 2). The IED + PD group were more likely endorse the presence of major depressive disorder, other mood disorder, and substance use disorder than either the IED or PD group. The IED + PD group was also more likely than the IED group (but not the PD group) to endorse a history of an anxiety disorder and an eating disorder. The PD group had a higher prevalence of any anxiety disorder and any eating disorder than the IED group. The IED + PD group also endorsed higher rates of all PDs assessed than those in the PD group [χ2(1) = 15.01–40.54, all p < .001]. There was also a significant effect of diagnostic group on measures of aggression [BPAQ total F(3,696) = 147.30, p < .001], impulsivity [BIS total F(3,720) = 63.73, p < .001], and affect lability [ALS total F(3,743) = 150.60, p < .001]. As Table 2 shows, for both impulsivity and aggression, Control participants had the lowest scores, the IED and PD group did not differ from each other, and the IED + PD participants showed the highest levels of aggression and impulsivity. For affect lability there was a monotonic trend with the IED + PD group showing the greatest level of affect lability, followed by the PD group, then the IED group, and finally the Control group with the lowest affect lability score. Another series of χ2 tests revealed that several demographic and other study variables were associated with NSSI and suicide attempts (see Table 3). First, race was significantly associated with both NSSI [χ2(2) = 7.63, p = .02] and suicide attempts [χ2(2) = 33.14, p < .001]. Individuals of “Other” races endorsed higher rates of NSSI and suicide than expected, African Americans endorsed higher rates of suicide than expected, and Caucasians endorsed lower rates of suicide than expected. Level of education was also significantly associated with suicide attempts [χ2(1) = 21.68, p < .001] but not NSSI, with individuals who did not attend college reporting greater incidence of suicide attempts. Neither age nor sex was significantly associated with NSSI or suicide attempts (all p > .34). NSSI and suicide attempts were also significantly associated with all forms of comorbid psychopathology assessed [χ2 = 7.66–159.39, all p ≤ .006]. Table 3. Demographic and study variables as a function of NSSI and suicide attempt history. No NSSI NSSI No suicide attempt Suicide attempt % Female 52.9% 57.1% 52.6% 60.0% Race % Caucasian 60.0% 55.6% 61.8% 43.4%*** % African-American 26.1% 22.7% 24.2% 33.1%** % Other 13.9% 21.7%* 13.9% 23.4%*** Level of education % No college 13.6% 16.8% 12.1% 27.8%*** Mean age (SD) 35.52 (10.50) 34.43 (9.32) 35.11 (10.36) 35.32 (9.81) Psychopathology Major Depressive Disorder 26.4% 63.6%*** 27.9% 69.7%*** Any other Mood Disorder 7.7% 14.1%** 7.2% 20.0%*** Any Anxiety Disorder 24.3% 46.5%*** 23.7% 60.7%*** Any Substance Use Disorder 29.0% 50.5%*** 29.3% 57.2%*** Any Eating Disorder 4.5% 18.2%*** 5.6% 17.2%*** Cluster A PD 7.1% 13.1%** 6.4% 20.0%*** Borderline PD 11.5% 40.9%*** 11.4% 53.8%*** Any other Cluster B PD 13.6% 27.8%*** 13.5% 33.1%*** Cluster C PD 15.7% 32.8%*** 16.3% 35.2%*** Associated variables Aggression (BPAQ) 68.67 (23.95) 89.80 (22.60)*** 70.34 (24.45) 89.28 (23.62)*** Impulsivity (BIS) 61.71 (10.82) 69.95 (11.07)*** 62.11 (10.91) 71.35 (10.94)*** Affect Lability (ALS) 91.46 (31.68) 119.94 (34.98)*** 92.85 (32.76) 125.16 (30.26)*** Note. NSSI = non-suicidal self-injury; *p < .05; **p < .01; ***p < .001. BPAQ = Buss Perry Aggression Questionnaire, BIS = Barratt Impulsivity Scale, ALS = Affect Lability Scale. Table options With respect to potential intervening variables, NSSI + participants reported greater levels of aggression [BPAQ t (695) = 9.14, p < .001], impulsivity [BIS t (719) = 7.88, p < .001], and affect lability [ALS t (742) = 9.24, p < .001] than individuals with no history of NSSI. Likewise, individuals with a history of suicide attempts reported greater levels of aggression [BPAQ t (695) = 6.58, p < .001], impulsivity [BIS (719) t = 9.23, p < .001], and affect lability [ALS t (742) = 8.72, p < .001] relative to those with no suicide attempt history. 3.2. Prevalence of self-harm Prevalence rates among the total sample were 18% (n = 194) for NSSI and 13.2% (n = 142) for suicide attempts. In addition, 41% of the sample who reported a history of NSSI also endorsed a past suicide attempt. Within the Control group, 3.7% (n = 13) endorsed any type of self-harm, 3.5% (n = 12) endorsed NSSI, and .3% (n = 1) endorsed a suicide attempt. In the IED group, 17.6% (n = 12) endorsed any type of self-harm, 12.3% (n = 9) endorsed NSSI, and 8.1% (n = 6) endorsed a suicide attempt. In the PD group, 21.8% (n = 47) endorsed any self-harm, 20.1% (n = 42) endorsed NSSI, and 11.1% (n = 24) endorsed a suicide attempt. Finally, in the IED + PD group, 41.8% (n = 189) endorsed any type of self-harm, 30.7% (n = 135) endorsed NSSI, and 25.4% (n = 114) endorsed a suicide attempt. 3.3. Association between diagnosis and self-harm Omnibus Pearson χ2 analyses revealed that diagnostic status was significantly associated with history of NSSI and suicide attempt [χ2(3) = 96.90–109.29, both p < .001]. Single degree of freedom Pearson χ2 analyses revealed that individuals with IED, PDs, and comorbid IED + PD were significantly more likely than Controls to have engaged in NSSI and attempted suicide. Furthermore, those with comorbid IED + PD were significantly more likely than those with PD or IED alone to endorse a history of NSSI or suicide attempt. Individuals with IED or PD alone were not significantly different from one another in regard to either NSSI or suicide attempts (see Table 4). Table 4. Pearson χ2 tests examining the likelihood of engaging in self-harm by diagnostic group. NSSI Suicide Attempt IED versus Controls 9.89** 22.74*** PD versus Controls 40.85*** 37.96*** IED + PD versus Controls 94.03*** 99.76*** IED versus PD 2.20 .66 IED + PD versus IED 10.45** 10.78*** IED + PD versus PD 8.01** 16.75*** Note. NSSI = non-suicidal self-injury; **p < .05; ***p < .001. Table options Hierarchical logistic regressions indicated that diagnostic status significantly predicted NSSI, after controlling for relevant diagnostic and demographic correlates. Diagnostic and demographic correlates were controlled for if they significantly predicted both study diagnostic group as well as NSSI or suicide attempt. First, compared to Controls, a diagnosis of IED significantly predicted a history of suicide attempt [OR = 17.72 (1.56–201.29), p = .02], but not NSSI (controlling for major depression, any other mood disorder, any substance use disorder, and any anxiety disorder). Similarly, having a PD significantly predicted a history of suicide attempt [OR = 10.09 (1.07–93.43), p = .04], but not NSSI (controlling for major depression, any other mood disorder, any substance use disorder, any anxiety disorder, and any eating disorder). Next, a diagnosis of IED + PD significantly predicted a history of NSSI [OR = 7.06 (3.39–14.72), p < .001] and suicide attempt [OR = 37.51 (4.89–287.51), p < .001] (controlling for major depression, any other mood disorder, any substance use disorder, any anxiety disorder, and any eating disorder in both analyses). Compared to individuals with IED alone, a diagnosis of IED + PD significantly predicted a history of NSSI [OR = 2.45 (1.15–5.20), p = .02] and suicide attempts [OR = 2.46 (1.01–6.00), p = .048] (controlling for major depression, any other mood disorder, any substance use disorder, any anxiety disorder, and any eating disorder in both analyses). Similarly, compared to individuals with PD alone, a diagnosis of IED + PD significantly predicted a history of NSSI [OR = 1.56 (1.03–2.35), p = .04] and suicide attempts [OR = 2.20 (1.34–3.61), p = .002] (controlling for major depression, any other mood disorder, and any substance use disorder in both analyses). 3.4. Intervening variables For each mediation result, the coefficient of the indirect effect (bootstrap standard error), Normal theory p-value (which should be interpreted with caution as it based on assumptions of normality), and bootstrap 95% confidence interval is reported. The indirect effect is considered significant at p < .05 if the 95% confidence interval does not contain zero. In each analysis, relevant diagnostic correlates were included (see above). 3.4.1. Aggression Scores on the BPAQ had a significant indirect effect on the relationship between PD and NSSI [effect = .35(.15), p = .002, CI = .12–.68], and IED + PD and NSSI [effect = .50(.19) p = .006, CI = .15–.88]. Scores on this scale did not significantly affect the relationship between IED and NSSI, IED and suicide attempts, PD and suicide attempts, or IED + PD and suicide attempts. 3.4.2. Impulsivity Scores on the BIS had a significant indirect effect on the relationship between IED + PD and NSSI [effect = .18(.10) p = .02, CI = .04–.41], and IED + PD and suicide attempts [effect = .19(.11) p = .04, CI = .004–.46]. Scores on this measure did not significantly affect the relationship between IED and NSSI or suicide attempts, nor PD and NSSI or suicide attempts. 3.4.3. Affect lability Scores on the ALS had a significant indirect effect on the relationship between IED + PD and NSSI [effect = .36(.15) p = .006, CI = .09–.68]. Scores did not significantly affect the relationship between any other diagnosis and NSSI or suicide attempt.