The impact of personality disorders and personality traits on psychotherapy treatment outcome of eating disorders: A systematic review

Abstract

A significant proportion of those with eating disorders (EDs) do not respond to first‐line treatments. This systematic review was conducted to identify whether personality disorders (PDs)/traits predict or moderate ED treatment outcomes and whether these outcomes were differentially influenced by ED or PD diagnostic subtypes, or treatment approach. A comprehensive systematic literature search was conducted using the PRISMA guidelines. A total of seven randomised controlled trials (RCTs) plus four follow‐up studies were reviewed investigating the impact of PD and PD traits on treatment outcomes for EDs. The majority indicated that PD had some impact on treatment outcomes. Outcome measures and time‐point measurements varied across studies. Included studies suggested that bulimia nervosa treatment outcomes were not hindered by co‐morbidity of borderline PD; however, psychiatric impairment remained high at post‐treatment and follow‐up. Cluster C PDs were found to negatively impact treatment outcomes for binge ED and attrition rates for anorexia nervosa. Included studies suggested that interventions that addressed aspects of personality pathology showed greater main effects for ED treatment outcomes. There is an urgent need for future RCTs on ED treatments to include routine measures of core personality features to allow their impacts to be more thoroughly examined and for psychotherapies to be tailored accordingly.

Reciprocal relationships between personality disorders and eating disorders in a prospective 17‐year follow‐up study

“…This is a recurring methodological challenge when studying the relationship between PD and ED. Comorbid PD is associated with complications to clinical care and could possibly represent barriers to recovery that should be addressed in therapy (Simpson et al, 2021) in mind, BMI was controlled for in the MLM analyses, and it did not seem to significantly impact the ED-PD comorbidity. Regardless of this, we cannot exclude the possibility that the occurrence of PD would differ had the patients achieved normal weight.…”

“…Comorbid PD in patients with ED are associated with increased levels of general psychopathology despite high treatment utilization (Cassin & von Ranson, 2005 ; Keel et al, 2002 ; Voderholzer et al, 2021 ; Zeeck et al, 2007 ), making this a matter of clinical importance. A recent systematic review (Simpson et al, 2021 ) revealed mostly unfavorable treatment outcomes for ED, possibly because ED symptoms tend to become more severe and intractable when occurring alongside a PD. The comorbidity of PD and ED may initiate self‐reinforcing feedback, exacerbating the role of ED symptoms as dysfunctional affect regulating and coping strategies (Helverskov et al, 2010 ; Sansone & Sansone, 2010 ; Simpson et al, 2021 ).…”

“…A recent systematic review (Simpson et al, 2021 ) revealed mostly unfavorable treatment outcomes for ED, possibly because ED symptoms tend to become more severe and intractable when occurring alongside a PD. The comorbidity of PD and ED may initiate self‐reinforcing feedback, exacerbating the role of ED symptoms as dysfunctional affect regulating and coping strategies (Helverskov et al, 2010 ; Sansone & Sansone, 2010 ; Simpson et al, 2021 ). Similarly, PD traits like impulsivity, perfectionism, rigidity, and interpersonal problems may delay or compromise ED recovery by increasing the risk of reduced therapeutic alliance and premature drop‐out from treatment (Chen et al, 2011 ; Hessler et al, 2019 ; Pham‐Scottez et al, 2012 ).…”

An exploratory study of associations between the ICD-11 personality disorder model and eating pathology

“…Perhaps most prominently, the novel ICD-11 personality disorder model takes a dimensional and trait-based approach, comprising general personality dysfunction and five more specific personality trait domains [ 8 , 9 ]. Although the ICD-11 will be used in clinical practice worldwide and despite the importance of personality for case formulations and personalized treatment of eating disorders [ 4 , 10 ], the relation of the ICD-11 personality disorder with eating pathology is, to date, unclear.…”

“…Personality is crucial for the onset, course, and treatment of eating pathology (for reviews, see [1][2][3][4]. Much of the previous research into the personality-eating pathology association has used categorical conceptualizations (i.e., presence vs. absence of an eating or personality disorder; e.g., [5]).…”