Aim: The aim of this study was to design and examine a program called the ‘pedometer walking plus motivational interviewing (PWMI) program’ in schizophrenic patients who are obese or overweight.

Methods: This was a 12-week, randomized, parallel, open-label, controlled trial in mildly ill schizophrenic patients with a body mass index (BMI) of 23.0 kg/m² or more. Each participant in the intervention or control group was given a leaflet entitled ‘What is a healthy lifestyle?’ The 1-week, PWMI program consisted of five 1-h sessions of individual motivational interviewing, group education, goal-setting, and practising of pedometer walking. The pedometers were given to the intervention group only. Weight, height, BMI and waist circumference were assessed at baseline, week 4, week 8, and week 12. The primary outcome of this trial was the changed bodyweight at week 4, week 8, and week 12.

Results: Of 64 participants, 32 each were randomly allocated to intervention and control groups. All participants completed the study. Only the means of changed bodyweight at week 12 were significantly different between groups (P = 0.03). At this week, the bodyweight of the intervention group decreased significantly more than that of the control group with a mean difference of 2.21 kg (95% confidence interval of 4.12–0.29).

Conclusion: Increased physical activity by pedometer walking plus individual motivational interviewing may be an effective program for the reduction of bodyweight and BMI in Thai schizophrenic patients who are obese or overweight. Its efficacy may be comparable to other cognitive/behavioral programs. Further studies in larger sample sizes are warranted.