Study participants
psychiatric, a mental disorder
Participants comprised adults (20 years of age or older) who met all of the following criteria: (1) diagnosed with a mental disorder and currently undergoing psychiatric outpatient treatment; (2) psychiatrist’s determination that the patients’ psychiatric symptoms were stable enough to allow participation in the study; (3) psychiatrist’s determination that participation in this study was not expected to interfere with psychiatric treatment; (4) able to communicate well enough to understand the explanation of the study and to make a decision on their own regarding study cooperation; and (5) able to participate in group discussion activities without difficulty using Japanese.The sample size was determined based on the effect size obtained from the results of a pilot randomized controlled trial (RCT) conducted prior to this study. An effect size of 0.5, α = 0.05, and β = 0.20, revealed the required sample size to be 33. The sample size was set to 40, considering dropouts. As the program was implemented on a group basis, the program implementation was planned and participants were recruited until more than 40 were enrolled. The final sample size was 45.