Data analysis
Composite scores with appropriate reverse coding of the responses in the outcome measures
were computed for analysis. Descriptive statistics were used to summarize participants’
characteristics, and the Shapiro–Wilk test was used to test the normality of data. The
chi-squared test (χWe compared the change scores of the outcome measures at posttest and at 1-month F/U from
pretest between the ACT and control groups and used nonparametric statistical tests
because these change scores did not meet the assumptions of normality. Specifically, the
Mann–Whitney We used intention-to-treat analysis (i.e. data from all participants are analyzed as
randomized); one participant in the control group, who did not complete the posttest and
the 1-month F/U evaluation, was included for analysis. The last observation carried
forward strategy was used to impute these missing values by considering that this
participant did not have any changes in outcome measures at each subsequent evaluation.
Statistical significance was set at 