Rate of Weight Gain of Inpatients with Anorexia Nervosa Under Two Behavioral Contracts

Abstract

Objective. To ascertain the rate of weight gain of inpatients with anorexia nervosa under two behavioral contracts, differing in criterion weight gain required to earn increasing privileges. Design. Follow-up comparison of cohorts receiving different interventions. Setting. Eating disorders service, operating on a general adolescent medicine unit. Patients. Patients admitted consecutively who met the following criteria: (1) weight at least 15% less than that expected for age, sex, and height; (2) female gender; (3) absence of chronic medical illness; (4) hospital stay of at least 28 days. Twenty-two patients meeting these criteria were treated between July 1987 and October 1988, when contract 1 was in effect. This cohort of patients was compared with a group of 31 patients, also meeting the these criteria, who were treated between November 1988 and December 1991, when contract 2 was in effect. Interventions. The behavioral contract, signed by the patient on admission, specifies the minimum 4-day weight gain necessary to earn increasing ward privileges, such as use of phone, frequency of visits, etc. Contracts 1 and 2 differed only in the 4-day weight gain criterion: 0.8 lb (0.36 kg) and 1.2 lb (0.55 kg), respectively. Results. The results of analysis of covariance, with admission weight as the covariate, revealed a significant interaction between contract and day, such that patients receiving contract 2 gained weight more rapidly (0.36 lb/d) than those receiving contract 1 (0.20 lb/d). There was no confounding difference between groups in the use of psychotropic medication, and no complications of refeeding in either group. Conclusion. Increasing the 4-day criterion weight gain from 0.8 to 12 lb in a behavioral contracting intervention was associated with a significant increase in the rate of weight gain, without an accompanying increase in complications of refeeding. This result simultaneously: (a) provides support for the efficacy of behavioral contracting and (b) reveals malleability in the rate of gain based on the targeted gain specified in the contract.