Occurrence and co-occurrence of nonsuicidal self-injury and disordered eating in a daily diary study: Which behavior, when?

Abstract

Although research has explored between-person traits that may account for the high rates of cooccurrence between non-suicidal self-injury (NSSI) and disordered eating (DE), little is known about within-person processes that predict which behavior occurs and when. This study describes the socioemotional contexts of NSSI and DE behaviors during a naturalistic, two-week daily diary period. Young adults (aged 18-35) who reported ≥ 1 episode of NSSI and ≥ 1 episode of DE (binge eating, purging, or fasting) during the two-week monitoring period were included (N = 25). NSSI and DE co-occurred approximately one third of the time. NSSI occurred following a greater number of interpersonal stressors and specific negative emotions, compared to DE.Participants were more likely to act on NSSI thoughts following arguments and feelings of rejection. They were more likely to act on binge eating/purging thoughts after eating or watching television, and when they felt self-hatred. They were more likely to act on fasting thoughts after discussing upsetting memories, and when they were in a public setting. NSSI days were also marked by more intense negative mood in the evenings relative to fasting days, and greater fatigue in the morning relative to binge eating/purging days. This study underscores the utility of using experience sampling methods to develop and test within-person models to advance our understanding of co-occurring behaviors.

Putative Risk Factors for Non‐Suicidal Self‐Injury in Eating Disorders

“…Gonçalves et al, 2016b; Islam et al, ). According to evidence that suggests that a higher likely of NSSI engagement acts on binge eating/purging thoughts or behaviours (Turner, Yiu, Claes, Muehlenkamp, & Chapman, ), in our study, patients engaging in NSSI reported more objective bulimic episodes and binge eating behaviours. Therefore, patients with ED types that include binge and/or purge behaviours may face increased risk of NSSI.…”

Behavioral functions underlying NSSI and eating disorder behaviors

“…MI analyses indicated that the same item‐factor structure was supported across NSSI and ED for 9 out of 13 ISAS scales, suggesting that similar functions are relevant to understanding why people engage in both these behaviors. The finding that both behaviors are equally multidetermined and motivated by similar functions may underlie why NSSI and ED co‐occur and are sometimes used as interchangeable coping strategies (Turner et al, ). The data also suggest that some functions, specifically self‐care, sensation seeking, and antisuicide, were not equally relevant to the behaviors.…”

“…The high comorbidity and numerous shared risk factors between these behaviors suggest that they may share similar pathogenesis (see Claes & Muehlenkamp, for a review). ED and NSSI behaviors are often concurrent (Turner et al, ), and may share similar thoughts and emotions preceding the symptomatic behavior (Shingleton et al, ; Turner, Yiu, Claes, Muehlenkamp, & Chapman, ). For example, high arousal negative affect states are consistently found to precede acts of NSSI (Hamza & Willoughby, ; Muehlenkamp et al, ), which is congruent with the emotional states antecedent to disordered eating behavior (Crosby et al, ; Vieira, Ramalho, Brandão, Saraiva, & Gonçalves, ).…”

Comparing self‐harming intentions underlying eating disordered behaviors and NSSI: Evidence that distinctions are less clear than assumed

“…When separating ED behaviors from other indirect forms of self‐harm, NSSI and ED behaviors show similarly strong associations with self‐criticism (Zelkowitz & Cole, ). Moreover, substantial comorbidity between NSSI and ED behaviors, alongside evidence that ED behaviors can co‐occur with NSSI (i.e., within an episode; Shingleton et al, ; Turner, Yiu, Claes, Muehlenkamp, & Chapman, ), suggests that there may be some shared intent to harm oneself via NSSI and ED behaviors. Indeed, ED behaviors can be painful (Selby et al, ; Smith et al, ), can result in substantial physical damage over both the short‐ and longer‐term (e.g., Claes & Muehlenkamp, ; Møhl et al, ; St. Germain & Hooley, ), and there is preliminary evidence that some people spontaneously categorize ED behaviors as a form of self‐harm (e.g., Laye‐Gindhu & Schonert‐Reichl, ).…”