Substance use disorders and eating disorders are common cohorts: eating disorders can occur in 20% to 30% patients with substance abuse disorders (Int J Eat Disord 1994; 16:1). A third comorbidity can be personality disorders, which have been reported in from 11% to 26% of patients with concurrent eating disorders and substance use disorders (Addict Behav 2006; 31:1761).

Two University of Toronto clinicians, Christine Courbasson and Jacqueline M. Brunshaw, recently designed a pilot study to investigate whether treatment for patients with concurrent substance use disorders and eating disorders might also improve borderline personality disorders (In J Environ Res Public Health 2009; 6:2076). The study was stimulated by reports that patients with the triad of personality, substance use, and eating disorders no longer met the criteria for personality disorders when they were successfully treated for the other two disorders.

The pilot study

Twenty outpatients (17 females and 3 males) who had completed a concurrent treatment program for substance use and eating disorders at a large metropolitan mental health center made up the study group. The candidates for the study completed a series of questionnaires, and then participated in a treatment plan that included weekly individual and group therapy sessions, as well as meetings with dietitians and psychiatrists as needed. Six patients received psychotropic medication. The participants were free to accept, reject, or withdraw from the study at any time.

The emphasis in the therapy sessions was on identifying and reducing vulnerability to personal triggers. Motivational interviewing, mindfulness training and behavioral and cognitive therapy were used. Study participants also learned about healthier eating and sleeping, and new ways to monitor and adapt to emotions.

What the results showed

At the end of the study, patients had attended an average of 68 individual sessions, 50 two-hour group sessions, 3 appointments with a dietitian, and had 11 phone coaching sessions. Six individuals also attended 8 appointments with psychiatrists.

After undergoing concurrent treatment of substance use and eating disorders for an average of almost 2 years, most patients had a statistically and clinically significant reduction in symptoms of substance, eating, and personality disorders. The authors theorize that there were four reasons for this. First, treatment may have affected the symptoms of substance use, eating disorders and personality disorders simultaneously, because treatment designed to decrease problematic substance use and eating behavior often involves changing the way a person manages emotions, copes with stress, solves problems, and relates to others.

Next, the reduction in eating disorder and personality disorders may reduce personality disorder symptoms that underly an eating disorder and a substance use disorder. Both may require significant behavioral and personality changes, including avoiding people, due to shame about the disordered behavior, and disgust about appearance, for example. Patients with eating disorders may become rigid and compulsive in adhering to a strict routine to avoid gaining weight, symptoms also associated with obsessive-compulsive personality disorder.

A third possibility is that reducing symptoms of personality disorder might in reality precede reduction in eating disorders and substance use disorders, in that treatment works to reduce problematic personality and behavioral tendencies that maintain these two disorders. Last, the reduction in eating, substance use, and personality disorders symptoms might reflect a problem with diagnostic assessments. According to the authors, many symptoms that are characteristic of personality disorders may be attributable to eating disorders and substance use disorders. For example, one of the symptoms of BPD is self-damaging impulsivity, such as substance abuse or binge eating. Because of comorbidities, the criteria used to diagnose personality disorders may not apply to cases with concurrent substance use and eating disorders and it is important to evaluate the true source of shared symptoms.

Further research will help clinicians better understand this triad and could help lessen the stigma of these patients as difficult and untreatable. This was only a pilot study; however, the authors feel their preliminary results do offer hope to clinicians and patients who are dealing with this difficult combination of interrelated symptoms.