Substance Abuse Is Increased in Patients with AN and BN

A person with an eating disorder is nearly 5 times more likely to abuse alcohol and drugs than is someone from the general population. Further, in previous research, the prevalence of substance abuse has been reported to be as high as 50% in individuals with eating disorders, compared with 9% in the general population.

A recent study explored substance abuse disorders among patients with different subtypes of anorexia nervosa (AN). Dr. Tammy L. Root, from the University of North Carolina, Chapel Hill, and a group of international researchers recently sought to determine the prevalence of coexisting eating disorders and substance abuse disorders among AN patients with different types of AN. The groups included women with AN, restricting type (RAN); AN with purging only (PAN); AN with binge-eating only (BAN); and those with a lifetime history of AN and bulimia nervosa (ANBN). The 731 women in the study were drawn from the International Price Foundation Genetic Studies (Int J Eat Disord 2010; 43:14).

The researchers particularly wanted to learn more about the effects of binge-eating and purging upon substance abuse among patients with AN, citing discrepancies in the literature about the frequency with which lifetime substance abuse co-occurs with AN, a lack of studies of substance abuse across well-defined subtypes of AN, and how this is affected by binge-eating in a low-weight state. They also wanted to explore the purging-only subtype of AN (PAN).

Demographic information collected included age at the time of the interview, duration of the eating disorder, and the highest and lowest self-reported lifetime body mass index (BMI, kg/m²). Eating disorder diagnoses were established by using the structured Inventory of Anorexia Nervosa and Bulimic Syndromes, a semi-structured clinical interview designed to establish DSM-IV and ICD-10 eating disorders diagnoses, and an expanded version of Module H of the Structured Clinical Interview of DSM-IV (SCID). Lifetime alcohol abuse and dependence and lifetime drug abuse and dependence were assessed using the SCID.

Results

Substance abuse disorders were most common among women with the ANBN subtype; those who endorsed purging behavior had higher rates of substance use disorders compared with those who did not report purging; and the prevalence of drug use differed according to binge eating status.

Across the sample, 19.8% of the women met criteria for lifetime history of alcohol abuse/dependence; the prevalence was highest among those with ANBN (35.5%) and lowest in those with restrictive-type AN, or RAN (13.7%). The risk for alcohol abuse/dependence was 3.20 times greater in the ANBN group and 1.85 times greater in the BAN group than among the RAN group. Among all the study participants, cannabis was the most frequently reported drug abused. Risk for abuse of all types of substances was highest in the ANBN group and lowest in the RAN group. Those in the ANBN group were 6.55 times more likely to report stimulant use, 5.89 times more likely to report cocaine use, 4.75 times more likely to report sedative use and 5.44 times more likely to report “other” drug use compared with those in the RAN group.

The authors note that the finding that greater substance use occurred in the purging group suggests that there may be meaningful characteristics associated with classification based on the presence or absence of purging. Also, their discovery that substance abuse occurred among individuals with RAN challenges the commonly held belief that individuals with the restrictive form of AN rarely report using drugs of alcohol. The study results also suggested that binge-eating was related to substance use under certain conditions. Risk of alcohol abuse/dependence and drug abuse/dependence were higher in those who reported binge-eating at low weight in relation to those who did not binge-eat; however, no differences emerged between those who binge-ate at low weight versus those who binge-ate only after weight was restored.

According to the authors, the results of this study are a reminder of the need to carefully assess alcohol and drug use behavior when screening and treating individuals with AN, particularly those who also have bulimic symptoms. Such patients may be at increased risk for physical complications, including elevated risk of death, as well as psychological comorbidities.