Predicting nonsuicidal self-injury episodes over a discrete period of time in a sample of women diagnosed with bulimia nervosa: An analysis of self-reported trait and ecological momentary assessment based affective lability and previous suicide attempts




To examine the moderating effect of trait affective lability on the relationship between past suicidal behavior and future nonsuicidal self-injury (NSSI).


A total of 127 adult females diagnosed with bulimia nervosa took part in this study. We hypothesized that individuals with greater levels of self-reported trait affective lability and a greater number of past suicide attempts would engage in a greater number of NSSI episodes over the course of 2 weeks than would individuals lacking elevations in one or both of those variables, controlling for average level of negative affect and affective lability as measured through ecological momentary assessment (EMA).


The two-way interaction of trait affective lability and past suicidal behavior predicted participants' number of NSSI episodes during the course of the study.


Interaction of self-reported trait affective lability and past suicidal behavior may exhibit clinical utility in the prediction of patients' imminent risk of engaging in NSSI. © 2011 by Wiley Periodicals, Inc. (Int J Eat Disord 2012; 45:808–811)


Rates of nonsuicidal self-injury (NSSI) are high among individuals diagnosed with eating disorders (EDs),1, 2 particularly in the bingeing-purging subtype of anorexia nervosa and bulimia nervosa (BN; for a review see the study by Svirko and Hawton3). The high co-occurrence between NSSI and EDs may be explained by shared etiological and maintenance factors.3 For example, both behaviors have been posited to serve as emotion regulation strategies. Indeed, intrapersonal negative reinforcement is one of the most commonly endorsed reasons for engaging in NSSI in general4 and this pattern remains true for ED patients who engage in NSSI, who most frequently endorse the affect regulation function.1 With this in mind, it is important to recognize that a tendency to experience frequent shifts in emotional intensity and valence (i.e., affective lability) may be an important factor in dysregulated behaviors (e.g., NSSI) in patients with BN. Anestis et al.,5 for instance, found that affective lability predicted impulsive behaviors (e.g., self-injury, risky sexual behavior) in a sample of women with BN. Research therefore suggests that individuals diagnosed with BN who experience frequently shifting moods are more likely to engage in a broad array of dysregulated behaviors.

Other stable tendencies, such as past suicide attempts, are also associated with NSSI. Individuals with a history of NSSI are more likely to report past suicide attempts6 and attempt suicide in the future7 relative to individuals with no history of NSSI. A longer history of NSSI is also associated with increased suicide attempts in adolescents,6 and individuals with a history of both suicide attempts and NSSI (as compared with suicide attempts alone) exhibit more severe psychopathology and suicidal ideation.8 This is of particular concern in BN, given that 25–35% of patients with BN attempt suicide (for a review see the study by Franko and Keel9).

Although the above referenced research supports the independent role of suicidal behavior and affective lability in the prediction of NSSI, to our knowledge, no past research has tested the interactive effect of these two variables and, as such, it is unclear to what extent the strength of the relationship between on predictor and NSSI depends upon the presence of the other predictor. The aim of this study was to determine whether levels of affective lability impact the strength of the relationship between prior suicidal behavior and NSSI episodes over a discrete period of time. Specifically, we hypothesized that, in a sample of women diagnosed with BN, the interaction of self-reported trait affective lability and lifetime number of suicide attempts would predict participants' number of NSSI episodes during the course of the study.


Participants and Procedure

The sample consisted of 127 female participants aged 18–55 (mean = 25.34, standard deviation = 7.71), all of whom met criteria for BN. The ethnic composition of this sample was 96.9% Caucasian, 1.5% Native American, 0.8% Asian, and 0.8% other. For a thorough description of the procedure utilized in this study, please see the study by Anestis et al.10


Axis I Psychopathology

The structured clinical interview for DSM-IV axis I diagnoses (SCID-I/P)11 is a semi-structured diagnostic interview used to assess DSM-IV-TR axis I psychopathology. Based on a random selection of 25 interviews, kappa ratings of inter-rater reliability for this sample were 1.00.

Predictor Variables

The dimensional assessment of personality pathology-basic questionnaire (DAPP-BQ)12 is a self-report measure comprised of 290 items used to assess several components of personality. Only the affective lability (I often feel like I am on an emotional roller coaster) subscale (α = 0.89) was utilized in the subsequent analyses.

The diagnostic interview for borderlines-revised (DIB-R)13 is a semi-structured diagnostic interview that measures borderline personality disorder symptoms. In this study, an item assessing the number of “suicidal gestures or attempts” participants had experienced during their lifetimes was used. Individuals who reported more than one gesture were given a score of 2; one attempt or gesture was scored as a 1; and not endorsing any suicidal gesture or attempt resulted in a score of 0. In a sample of 25 randomly selected cases, the interclass correlation coefficients (ICC) ranged from 0.75 to 1.0 for subscales and 0.98 for the global score.

Outcome Variables

ED and self-destructive behavior checklist. Several items from various questionnaires14, 15 were consolidated into a measure of behavioral dysregulation. In this study, a composite NSSI variable was created by summing the total number of times each participant endorsed any of the following behaviors: cutting, burning, repeated hitting, and head banging.


The eating disorder examination (EDE)16 is a semi-structured interview that assesses ED symptomatology. In this sample, a random selection of 25 cases resulted in interclass coefficients ranging from 0.65 to 0.98, indicating sufficient inter-rater reliability. Only the global score was utilized.

The positive affect–negative affect scale (PANAS)17 is a 20-item self-report questionnaire utilized to assess the degree to which an individual is currently experiencing positive and negative affect. Items utilize a Likert-type scale ranging from 1 (“Very slightly or not at all”) to 5 (“Extremely”). In this study, the PANAS was filled out several times per day over a period of 2 weeks. Only the negative affect subscale was utilized.

The mean square successive difference (MSSD) was used to create a single affective lability coefficient. In the context of this study, this variable represented the degree to which, on average, each participant's level of negative affect differed from the level that preceded it. The formula for this procedure, which consists of nelements, the ith of which is denoted as xi is as follows:

equation image

In addition to calculating affective lability using the PANAS negative affect subscale, we also calculated the mean level of negative affect experienced by each participant during the course of the study. The purpose of this calculation was to differentiate between mood variability and intensity.

The Hamilton depression rating scale (HAM-D)18 is a 21-item semi-structured interview that assesses symptoms of major depressive disorder (MDD). Questions measure the degree to which specific symptoms of MDD (e.g., difficulty with sleep, depressed mood, psychomotor retardation) are present in the interviewee.


Means, standard deviations, and intercorrelations for the variables utilized in these analyses can be found in Table 1.

Table 1. Means, standard deviations, and intercorrelations for all variables utilized in the analyses
  1. *p < .05.

  2.  **p < .01.

1. Average negative affect      
2. EMA affective lability0.16     
3. Depression0.11**0.30    
4. Global EDE score0.13**0.28**0.46   
5. Previous suicide attempts0.050.14**0.270.08  
6. DAPP affective lability**0.29**0.27**0.26**0.34**0.24 
7. Self-injury episodes0.**0.40*0.19

Interaction of DAPP Affective Lability and Previous Suicide Attempts predicting NSSI Episodes

To test our hypothesis, a hierarchical linear model based on ordinary least squares regression was conducted. All variables utilized in this analysis were centered at their mean. In Step 1, the covariates were entered. In Step 2, the main effects were entered. In Step 3, the product of DAPP affective lability and suicide attempts was entered. Number of self-reported NSSI episodes during the study served as the dependent variable. Results indicated that the interaction between DAPP affective lability and previous suicide attempts was significantly related to participants' number of NSSI episodes during the course of the study (t = 4.01, p < 0.001, sr = 0.31, f2 = 0.48; See Table 2 and Figure 1).

Figure 1..

Interaction of trait affective lability and lifetime number of suicide attempts predicting nonsuicidal self-injury episodes during the course of the study. Values in graph represent variables centered at their respective means.

Table 2. The interaction of DAPP affective lability and previous suicide attempts predicting number of NSSI episodes, controlling for average levels of negative affect, EMA affective lability, depression, and global EDE scores
 R2 for SetT-Valuep-ValueCorrelations
  1. Dependent variable: Number of self-injury episodes.

Average negative affect 0.077.939.035.007.007
EMA affective lability 0.816.416.116.075.075
Depression 0.290.773.099.027.026
Global EDE score 0.890.375.130.082.081
Average negative affect 0.000.999.035.000.000
EMA affective lability 0.367.715.116.034.030
Depression −1.040.301.099−.096−.084
Global EDE Score
Suicide attempts 5.665.000.481.467.458
DAPP affective lability 0.507.613.170.047.041
Average negative affect 0.207.836.035.019.016
EMA affective lability 0.129.897.116.012.010
Depression −−.108−.088
Global EDE score
Suicide attempts
DAPP affective lability 0.951.344.170.089.072
Suicide attempts × DAPP affective lability


The central aim of this study was to examine whether trait affective lability and lifetime number of suicide attempts would interact to predict the number of episodes of NSSI that occurred over a two week period in a sample of women diagnosed with BN. Results supported the hypothesis that higher levels of self-reported affective lability and previous suicidal behavior would be associated with a greater amount of self-injury. Specifically, in the present sample of women diagnosed with BN, the strength of the relationship between prior suicidal behavior and future NSSI was dependent upon an individual's level of affective lability. These results are consistent with past research indicating that trait affective lability is associated with a greater number of dysregulated behaviors in women diagnosed with BN,5 as well as research indicating that a past history of suicidal behavior is predictive of NSSI,6 while extending the existing literature by exploring the interactive effect of these two constructs.

It is important to note a number of limitations to these findings. First, our entire sample was comprised of women diagnosed with BN and, as such, the generalizability of the findings is unclear. In addition, our item measuring past suicidal behavior asked participants to indicate their past number of “suicide gestures or attempts,” meaning that this variable was potentially comprised of somewhat varied behaviors. Future studies utilizing a suicidal behavior measure that more clearly defines suicidality is recommended. Finally, our EMA data were analyzed in an aggregate fashion, and, as such, statistical methods that capitalize on the full potential of the data were not available options.

Despite these limitations, we believe that this study offers significant insights into an important topic. These findings indicate that risk for NSSI can be effectively evaluated utilizing self-report measures of stable traits and that such measures offer incremental predictive utility above and beyond that of more complex EMA methodology within a sample of women diagnosed with BN. Clinically, these findings speak to the importance of considering multiple variables simultaneously when assessing risk for NSSI in the immediate future. Although the associations between both affective lability and past suicidal behavior with future NSSI are well established and make intuitive sense, empirical evaluations of the interactive effect of these variables provide a stronger foundation upon which to base risk assessments and allow for a more precise understanding of vulnerabilities. In this sense, although these findings do not represent a paradigm shift that counters previous findings, they represent a step toward adding specificity to the conceptualization of the associations between well-established risk factors for NSSI and actual NSSI episodes in discrete periods of time.

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