The moderating effect of age on the association between change language and change in alcohol use

To investigate whether participants' age plays a role in how change language measured during a brief motivational intervention (BMI) relates to change in weekly drinking consumption.

Secondary analysis of a randomized controlled trial carried out in an emergency room. The sample (N = 97, mean age: 38.7y, range: 18-83y; 80 % men) was divided in four age groups: late adolescents (18-21y, 19.6 %), young adults (22-29y, 22.7 %), adults (30-49y, 34.0 %) and older adults (≥50y, 23.7 %). BMI sessions were coded using the MI Skill Code 2.0, and four measures of change language were derived: frequency of change talk (CT, toward change), frequency of sustain talk (ST, against change), percentage of CT, and mean of strength. Weekly drinking consumption (i.e., number of standard drinks per week) was measured at baseline and at 12-month follow-up. To examine whether change language measures varied according to age, one-way ANOVA and linear regressions were used. Then, a moderation analysis studied the moderating effect of age group.

The 30-49y and ≥ 50y groups displayed a lower mean of strength when compared to 18-21y. The relationship between two change language measures (frequency of CT and mean of strength) and alcohol outcome was moderated by age. Specifically, higher levels of the two measures were related to greater decreases in weekly drinking only among late adolescents (18-21y) when compared to the other age groups.

This exploratory study suggests that age is an aspect to consider in BMI. Our results might partly explain the inconsistent findings in the literature examining the association between client language and behavior change.