Behavioral Intervention May Promote Weight Loss in Overweight and Obese Adults with Serious Mental Illness

EBM Focus - Volume 8, Issue 18

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Reference: N Engl J Med 2013 Apr 25;368(17):1594, (level 2 [mid-level] evidence)

Obesity is highly prevalent in patients with serious mental illness, a population in which physical activity tends to be low and unhealthy diets are common. The need for psychotropic medications can compound the problem, since many of these drugs induce weight gain by increasing appetite. Short-term behavioral interventions have previously shown some efficacy for limiting weight gain in this population in small trials (Cochrane Library 2007 Issue 1:CD005148), but large scale trials have been lacking. A recent trial evaluated an 18-month targeted behavioral program for weight loss in 291 adults with serious mental illness.

Patients receiving outpatient psychiatric rehabilitation at 10 centers (mean age 45 years) were randomized to 1 of 2 interventions. In the behavioral weight loss group, patients received tailored group and individual weight management sessions, and group exercise sessions, with goals of improved diet and increased aerobic activity. The control group received standard nutritional and exercise information at baseline and was given the option of general health classes on topics unrelated to weight. Healthy, reduced-calorie foods were available to all participants at breakfast and lunch at the rehabilitation centers. At baseline, the mean body mass index was 36.3 kg/m2 and mean weight was 102.7 kg (225.9 lbs). Diagnoses included schizophrenia or schizoaffective disorder in 58%, bipolar disorder in 22%, and major depression in 12%. About 90% were taking antipsychotic drugs, and 22% were taking clozapine or olanzapine, the 2 atypical antipsychotics associated with the most weight gain.

Follow-up data at 18 months were available for 96% of the participants. The median number of sessions attended in the behavioral intervention group was 2.5 per month. The rates of absenteeism for at least 30 consecutive days were about 25% over the first 6 months and about 50% during months 7-18. The behavioral intervention was associated with greater rates of achieving ≥ 5% weight loss (37.8% vs. 22.7%, p = 0.009, NNT 7), and ≥ 10% weight loss (18.5% vs. 7%, p = 0.007, NNT 9). At 18 months, the mean weight loss was 3.4 kg (7.5 lbs) in the intervention group vs. 0.2 kg (0.4 lbs) in controls (p = 0.002).

For more information, see the Schizophrenia, Bipolar disorder, and Obesity in adults topics in DynaMed.