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Overweight and obesity are epidemic among persons with serious mental illness, yet weight-loss trials systematically exclude this vulnerable population. Lifestyle interventions require adaptation in this group because psychiatric symptoms and cognitive impairment are highly prevalent. Our objective was to determine the effectiveness of an 18-month tailored behavioral weight-loss intervention in adults with serious mental illness.
We recruited overweight or obese adults from 10 community psychiatric rehabilitation outpatient programs and randomly assigned them to an intervention or a control group. Participants in the intervention group received tailored group and individual weight-management sessions and group exercise sessions. Weight change was assessed at 6, 12, and 18 months.
Of 291 participants who underwent randomization, 58.1% had schizophrenia or a schizoaffective disorder, 22.0% had bipolar disorder, and 12.0% had major depression. At baseline, the mean body-mass index (the weight in kilograms divided by the square of the height in meters) was 36.3, and the mean weight was 102.7 kg (225.9 lb). Data on weight at 18 months were obtained from 279 participants. Weight loss in the intervention group increased progressively over the 18-month study period and differed significantly from the control group at each follow-up visit. At 18 months, the mean between-group difference in weight (change in intervention group minus change in control group) was −3.2 kg (−7.0 lb, P = 0.002); 37.8% of the participants in the intervention group lost 5% or more of their initial weight, as compared with 22.7% of those in the control group (P = 0.009). There were no significant between-group differences in adverse events.
A behavioral weight-loss intervention significantly reduced weight over a period of 18 months in overweight and obese adults with serious mental illness. Given the epidemic of obesity and weight-related disease among persons with serious mental illness, our findings support implementation of targeted behavioral weight-loss interventions in this high-risk population.
Persons with serious mental illness, such as schizophrenia, bipolar disorder, and major depression, have mortality rates that are two to more than three times as high as the rate in the overall population, and the primary cause of death in such persons is cardiovascular disease.1–4 Concomitantly, this vulnerable population has an extremely high prevalence of obesity, nearly twice that of the overall population.5–9 Therefore, it is not surprising that persons with serious mental illness have an increased burden of weight-related conditions, including heightened risk of diabetes mellitus, hypertension, dyslipidemia, and certain cancers.10–15
Obesity is multifactorial in persons with serious mental illness. Physical inactivity and unhealthy diets are commonplace.16–18 In addition, many psychotropic medications, often required for long-term symptom control, cause weight gain, in part through increased appetite and the resultant high caloric intake.19–22 Hence, lifestyle interventions to modify diet and activity should have a central role in stemming the epidemic of obesity and obesity-related conditions23–25 in this group.
Yet persons with serious mental illness, particularly schizophrenia, often have impairments in memory and executive function, as well as residual psychiatric symptoms, that impede learning and adoption of new behaviors.26 Furthermore, low socioeconomic status probably contributes to reduced access to healthy foods and lack of affordable, safe places to exercise.17,27,28 Stigma associated with mental illness may also contribute to low levels of participation in mainstream leisure-time physical activities.29,30
Lifestyle interventions for overweight or obese persons with serious mental illness must address these special needs. Owing to concerns about adherence and ability to participate in groups, lifestyle-intervention trials in the general population typically exclude persons with serious mental illness.24,31–36 The few behavioral weight-loss trials targeting persons with serious mental illness have had short study periods, small samples, and other limitations.37,38 The purpose of our trial was to determine the effectiveness of an 18-month tailored behavioral weight-loss intervention in adults with serious mental illness who were attending community outpatient psychiatric rehabilitation programs.
Institutional review boards at Johns Hopkins University and Sheppard Pratt Health System and an independent data and safety monitoring board approved the protocol for the Randomized Trial of Achieving Healthy Lifestyles in Psychiatric Rehabilitation (ACHIEVE). All participants provided written informed consent. The first author designed the study, wrote the manuscript, and vouches for the accuracy of the data and analyses. The study was conducted according to the study protocol (available with the full text of this article at NEJM.org). No commercial weight-loss entity was associated with this study.
We placed the trial in outpatient psychiatric rehabilitation programs, settings that provide potentially unrealized opportunities to deliver lifestyle interventions. These programs serve large numbers of persons with serious mental illness and offer vocational and skills training, case management, and other services. Programs typically have commercial kitchens and communal space that can be used for multiple functions, including group exercise. Program enrollees often attend these programs multiple times each week, which facilitates the delivery of lifestyle interventions that involve frequent contact.
The study population consisted of overweight or obese adults (≥18 years of age) who attended 1 of 10 community psychiatric rehabilitation programs in central Maryland or their affiliated out-patient mental health clinics. The eligibility criteria were minimal; we aimed to enroll a broad population that would be representative of persons with serious mental illness attending community mental health programs.39 We excluded persons with a medical contraindication to weight loss, a cardiovascular event within the previous 6 months, an inability to walk, or an active alcohol-use or substance-use disorder (see the Supplementary Appendix, available at NEJM.org).
Participants were enrolled between January 2009 and February 2011. Study staff recruited participants by means of presentations at study sites and received referrals from rehabilitation-program staff.
Individual participants were randomly assigned to the intervention or control group. Randomization was stratified according to sex and study site; assignments were generated in blocks of two and four. Data collectors were unaware of the study assignments.
Rehabilitation programs routinely provided breakfast and lunch to all program attendees. To facilitate the availability of reduced-calorie food choices for participants in the intervention group, we advised kitchen staff on offering healthier meals at the programs (see the Supplementary Appendix).
The conceptual framework of the intervention incorporated social cognitive and behavioral self-management theories and was congruent with psychiatric rehabilitation principles of skill building and environmental supports.40–42 The intervention built on lifestyle interventions that studies have shown to be effective in the general population.32,36 In addition, it was tailored to address deficits in memory and executive function (e.g., by dividing information into small components and targeting skills repeatedly).43,44
The intervention was composed of three contact types: group weight-management sessions, individual weight-management sessions, and group exercise sessions. The goals for the intervention group included the following: reducing caloric intake by avoiding sugar-sweetened beverages and junk food (e.g., candy and high-fat snacks), eating five total servings of fruits and vegetables daily, choosing smaller portions and healthy snacks, and participating in moderate-intensity aerobic exercise (see the Supplementary Appendix).
Group exercise started at a level appropriate for sedentary persons, with gradual increases in duration and intensity.45 Trained members of the study staff led all exercise classes for the first 6 months. Subsequently, a trained member of the rehabilitation-program staff offered some exercise sessions using a video specifically prepared for this trial.
To reinforce the intervention goals, we asked participants to monitor key behaviors with the use of a simplified tracking tool and to meet with intervention staff to monitor their weight. Session attendance was incentivized with points that participants traded for small reward items.
Standardized procedures and materials promoted fidelity of the study staff to the intervention. Ongoing training and quality assurance included regular observation of intervention staff.
Participants in the control group received standard nutrition and physical-activity information at baseline. Health classes were offered quarterly, with content unrelated to weight (e.g., cancer screening).
Data collectors visited the rehabilitation programs to determine study eligibility, to collect baseline data, and to perform follow-up assessments at 6, 12, and 18 months. Height was measured at study entry. At each visit, weight was measured with the use of a high-quality, calibrated digital scale, with the participant wearing indoor clothing and no shoes. Measurements of blood pressure, waist circumference, and fasting blood chemical levels were obtained at baseline and at 6 and 18 months. Information on sociodemographic characteristics and medications were obtained from participant self-reports and program records; psychiatric diagnoses were abstracted from program records.
Analyses were conducted according to the intention-to-treat principle. Primary outcomes were changes in weight from randomization to 6 months and 18 months. Other weight-related outcomes included percentage of weight change from baseline, percentage of participants at or below baseline weight, percentages of participants who lost at least 5% of their initial weight and those who lost at least 10%, and change from baseline in body-mass index (BMI; the weight in kilograms divided by square of height in meters). Weight data obtained within a 45-day window before or after the data-collection points and data obtained before a protocol-defined censoring event (e.g., pregnancy) were included in the primary analysis, which was conducted with the use of a likelihood-based mixed-effects model, with weight as a function of study-group assignment and study visit (at baseline and at 6, 12, and 18 months) and with missing data treated as missing at random. The model was adjusted for study site and sex. An unstructured covariance structure was used to relate repeated measures, with the use of robust standard errors for statistical inferences.
The same modeling approach was applied to the change in BMI and to the percentage of weight change, with log-transformed weights used as outcome values. Percentages of participants in the two groups who met various weight-loss criteria were compared with the use of chi-square tests. Sensitivity analyses were performed by including weight data collected outside the data-collection window and were also conducted with adjustment for number of psychotropic medications.
The original enrollment target was 320 participants. The initial study design assumed a 20% loss to follow-up, resulting in an effective sample size of 256. This study design provided 86% power to detect a between-group difference in weight change of 2.0 kg (4.5 lb) at 18 months.
A total of 417 persons provided written informed consent for screening in the trial; of these, 291 underwent randomization (Fig. 1). The mean age was 45.3 years; 49.8% of the participants were men, and 38.1% were black (Table 1). More than half the participants lived in supported housing, and almost 80% were unable to work. A total of 58.1% of the participants had schizophrenia or a schizoaffective disorder, 22.0% had bipolar disorder, and 12.0% had major depression. The mean number of psychotropic medications was 3.1. On average, there were 29 participants per study site (range, 18 to 45). Follow-up weights were obtained from 279 participants, out of 280 for whom data were not censored at 18 months. At follow-up visits, 93.3% of the participants had their weight measured within the data-collection windows.
As compared with the control group, the mean net weight loss in the intervention group increased progressively over the 18-month study period. At 6 months, the mean change in weight from baseline was −0.3 kg (95% confidence interval [CI], −1.0 to 0.5 [−0.6 lb; 95% CI, −2.3 to 1.1]) in the control group and −1.8 kg (95% CI, −2.5 to −1.0 [−4.0 lb; 95% CI, −5.6 to −2.3]) in the intervention group. At 18 months, the mean change in weight from baseline was −0.2 kg (95% CI, −1.7 to 1.3 [−0.5 lb; 95% CI, −3.7 to 2.8]) in the control group and −3.4 kg (95% CI, −4.7 to −2.1 [−7.5 lb; 95% CI, −10.3 to −4.7]) in the intervention group (Fig. 2, and Table S2 in the Supplementary Appendix).
The mean net weight change (change in weight in the intervention group minus change in weight in the control group) at 6 months was −1.5 kg (95% CI, −2.6 to −0.4 [−3.3 lb; 95% CI, −5.7 to −0.9]). At 18 months, the net change was −3.2 kg (95% CI, −5.1 to −1.2 [−7.0 lb; 95% CI, −11.3 to −2.7]). These absolute differences in weight correspond to a percentage weight change of −1.7 percentage points (95% CI, −2.7 to −0.5) in favor of the intervention group at 6 months and −3.4 percentage points (95% CI, −5.4 to −1.4) at 18 months (see the Supplementary Appendix).
Table 2 displays the percentages of participants meeting certain weight-loss thresholds at 6, 12, and 18 months after randomization. Among participants in the intervention group, 63.9% had a weight at 18 months that was at or lower than their baseline weight, as compared with 49.2% of those in the control group. The percentage of participants who lost at least 5% of their baseline weight was 37.8% in the intervention group, as compared with 22.7% in the control group. At 18 months, the net difference in change in BMI for participants in the intervention group, as compared with those in the control group, was −1.1 (95% CI, −1.8 to −0.5) (see the Supplementary Appendix).
In sensitivity analyses, the findings were robust. An analysis that included weights obtained outside the data-collection windows had results that were consistent with those of the primary analysis (see the Supplementary Appendix), as did an analysis with adjustment for the number of psychotropic medications. Results for adiposity-related outcomes, including cardiovascular risk factors, are provided in the Supplementary Appendix.
Table 3 displays data on the numbers of group and individual weight-management sessions and group exercise sessions that were offered to and attended by participants in the intervention group. The median number of total attended sessions was 46 in the first 6 months and 31 in months 7 through 18. Attendance at the group exercise sessions contributed most to the total number of contacts.
Although the proportion of attended sessions, as compared with offered sessions, was lower after the first 6 months, the median number of contacts in the intervention group was approximately 2.5 per month. The percentage of participants in the intervention group who were absent from the rehabilitation program for 30 or more consecutive days was 27.3% during the first 6 months and 51.5% during months 7 through 18.
There were two deaths in the intervention group and three in the control group (see the Supplementary Appendix). A total of six cardiovascular events occurred in the intervention group, and eight occurred in the control group. No events were deemed to be probably or definitely study-related. At data-collection visits, 18.3% of the participants in the intervention group and 13.0% of those in the control group reported a medical hospitalization, and 14.8% of the participants in the intervention group and 20.6% of those in the control group reported a psychiatric hospitalization.
In overweight and obese adults with serious mental illness who were participating in psychiatric rehabilitation programs, a behavioral weight-loss intervention incorporating weight-management counseling and group exercise significantly reduced participant weight over a period of 18 months. In contrast to the findings in most studies of lifestyle intervention in the general population,24,32,34,36,49 weight loss did not peak early in the intervention group in this study population but instead progressed over the course of the trial. This finding suggests that despite substantial challenges, persons with serious mental illness are able to lose weight with a tailored intervention.
The amount of weight loss achieved in our trial — namely, a mean of 3.2 kg (7.0 lb) at 18 months — compares favorably with weight loss in lifestyle-intervention trials in the general population. This extent of weight loss, albeit modest, has been shown to have beneficial effects, such as a reduced risk of cardiovascular disease among persons with an initially elevated risk.23–25 However, the pattern of weight loss over time was distinct. The net weight loss at 18 months was 2.7 kg (6.0 lb) in Trials of Hypertension Prevention Phase II and PREMIER and 3.6 kg (8.0 lb) in the Trial of Non-pharmacologic Interventions in the Elderly.24,32,36 In these trials and others,24,32,34,36,49 weight loss was typically maximal at 6 months, with weight regained thereafter. In contrast, participants in the intervention group in ACHIEVE continued to lose weight after 6 months and did not regain weight, even with a reduced frequency of weight-management contact sessions and with rehabilitation staff assuming responsibility for some exercise classes. One possible explanation is that persons with serious mental illness take longer than those without serious mental illness to engage in an intervention and make requisite behavioral changes.
To date, few randomized trials of behavioral weight-loss interventions in persons with serious mental illness have been published, and all were short-term.37,38,50–52 A 2007 Cochrane review on weight loss in patients with schizophrenia identified five nonpharmacologic studies, none with a study period of more than 4 months.38 A trial involving 53 Taiwanese psychiatric inpatients that controlled caloric intake and offered group physical activity showed a mean weight loss of 5.2 kg (11.5 lb) at 6 months.53 Another trial in China that involved persons with new-onset schizophrenia with weight gain after the initiation of antipsychotic medication showed a net mean weight loss of 4.5 kg (9.9 lb) with a 3-month intervention.54 Most of the other studies were uncontrolled, and many had small samples.37,50,52
An important feature of our trial is the setting — namely, psychiatric rehabilitation programs. Although not all persons with serious mental illness attend these types of programs, they are often affiliated with outpatient clinics and therefore could serve as a hub for this or similar lifestyle interventions. We recognize that incorporating lifestyle interventions into rehabilitation programs or placing such programs in other mental health settings would require financial and organizational resources.
This trial has several strengths. First, we enrolled a diverse population of patients with serious mental illnesses from multiple community-based programs. We enrolled persons with a range of psychiatric diagnoses and did not require that patients be receiving treatment with a specific psychotropic regimen. In fact, the use of psychotropic medications that lead to weight gain19–22 was commonplace. A large proportion of participants had substantial psychiatric symptoms, as evidenced by baseline scores on the Behavior and Symptom Identification Scale,46 the Center for Epidemiologic Studies Depression Scale,47 and the Repeatable Battery for the Assessment of Neuropsychological Status.48 Despite psychotropic-medication use and ongoing psychiatric symptoms, participants in the intervention group had significant weight loss. Second, throughout the trial, we attained high follow-up rates for outcome data. Very few missing data and high correlations between weight measures allowed for robust statistical inferences (see the Supplementary Appendix). Third, the intervention was offered over a period of 18 months, in contrast to the short-term interventions in previous randomized trials of behavioral weight-loss interventions in this population.
Our trial has limitations. Over the course of the study, attendance at the intervention sessions and rehabilitation programs decreased; reasons included hospitalizations and social issues. However, the large number of offered contact opportunities allowed for continued exposure to the intervention sessions, even for persons with infrequent attendance. Thus, the trial reflects actual attendance patterns of persons with serious mental illness, who often have competing intercurrent issues.26 Second, the trial was not designed or powered to determine the effects of weight reduction on cardiovascular risk factors in this population. Hence, nonsignificant changes in blood pressure and fasting lipid and glucose levels (see the Supplementary Appendix) should be interpreted cautiously. Third, the trial was not designed to influence the prescribing of medication. In clinical practice, the consideration of psychotropic medications with less obesogenic potential for appropriate patients may help them reach weight goals. Fourth, our efforts to provide healthy meal options were available to all participants in the rehabilitation programs. This may have influenced weight in the control group. If so, the trial results are conservative.
In conclusion, our results show that overweight and obese adults with serious mental illness can make substantial lifestyle changes despite the myriad challenges they face. Given the epidemic of obesity and weight-related disease among persons with serious mental illness, our findings support implementation of targeted behavioral weight-loss interventions in this high-risk population.
Funded by the National Institute of Mental Health; ACHIEVE ClinicalTrials.gov number, NCT00902694.
Supported by the National Institute of Mental Health. Disclosure forms provided by the authors are available with the full text of this article at NEJM.org.