Effects of a behavioural weight loss intervention in people with serious mental illness: Subgroup analyses from the ACHIEVE trial

BACKGROUND

Persons with serious mental illnesses (SMI) such as schizophrenia and bipolar disorder have an increased risk of obesity and related chronic diseases and die 10-20years earlier than the overall population, primarily due to cardiovascular disease. In the ACHIEVE trial, a behavioural weight loss intervention led to clinically significant weight loss in persons with SMI. As the field turns its attention to intervention scale-up, it is important to understand whether the effectiveness of behavioural weight loss interventions for people with SMI, like ACHIEVE, differ for specific subgroups.

METHODS

This study examined whether the effectiveness of the ACHIEVE intervention differed by participant characteristics (e.g. age, sex, race, psychiatric diagnosis, body mass index) and/or their weight-related attitudes and behaviours (e.g. eating, food preparation, and shopping habits). We used likelihood-based mixed effects models to examine whether the baseline to 18 month effects of the ACHIEVE intervention differed across subgroups.

RESULTS

No statistically significant differences were found in the effectiveness of the ACHIEVE intervention across any of the subgroups examined.

CONCLUSIONS

These findings suggest that the ACHIEVE behavioural weight loss intervention is broadly applicable to the diverse population of individuals with SMI.

A pilot randomized controlled trial testing the effects of a routine-based intervention on outcomes in a behavioural weight loss programme

Background

Structured routines aimed at eating and sleep have been successfully employed in weight loss interventions for children. Although such routines are discussed in lifestyle modification programmes for adults, they are not a primary focus.

Purpose

The purpose of this study is to determine if establishing healthy eating and sleep routines may improve outcomes in a behavioural weight loss (BWL) intervention.

Methods

Twenty‐five overweight/obese participants (age = 52.4 ± 9.8; body mass index = 33.5 ± 4.1) were randomly assigned to either a 4‐week routine‐based intervention (ROU) targeting regular eating and sleep or an education control before beginning an 18‐week BWL intervention.

Results

Routine‐based intervention participants reported adhering to eating routines, with increased ‘on‐schedule’ eating (p = 0.007) and decreased ‘off‐schedule’ eating (p = 0.002) but showed no change in ‘on‐schedule’ sleep (p = 0.74). However, contrary to our hypothesis, ROU participants lost less weight than controls after 6 weeks of BWL (2.3 ± 2.5 vs. 4.6 ± 2.6 kg, p = 0.04) and achieved only modest weight loss over the full 18 weeks (ROU: 3.2 ± 4.6 vs. education control: 5.8 ± 5.7 kg, p = 0.23).

Conclusions

Focusing initially on establishing healthy sleep and eating routines led to poorer, rather than better, subsequent weight loss outcomes. Further studies using a longer initial intervention period or focusing on only sleep or eating behaviour are needed to determine whether establishing routines for eating and sleep behaviours can enhance weight loss in adults.