Measuring Participant Effort in a Depression Prevention Trial: Who Engages in Problem-Solving Therapy?

To determine the acceptability of clinical interventions for depression prevention, identification of clinical characteristics associated with intervention engagement is needed. The purpose of this study is to describe levels and correlates of participant engagement in Problem Solving Therapy (PST) in adults 60 and older with subthreshold depression.

As part of a clinical trial to prevent depression among older adults with subthreshold depression, participants who were randomized to receive PST completed 6-8 sessions in which they learned skills to solve self-selected problems that were contributing to stress and reduced quality of life. To measure participants' engagement with PST, interventionists completed 3 scales that rated participants' level of participation in problem solving activities, understanding of the multistep process of PST, and between-session homework effort. Using logistic regression, we examined whether physical health, level of cognitive function, gait speed, and disability served as correlates of engagement in the PST intervention.

Gait speed, a measure of physical and cognitive health, was significantly associated with engagement in PST. Participants who walked faster were more likely to engage with PST compared to participants who walked more slowly. No other baseline variables were significant correlates.

Older adults who walk more slowly may need alternative delivery methods to fully engage in PST. Gait speed reflects physical and cognitive health, and predicts frailty, disability, and psychomotor speed slowing. For these reasons, gait speed may be a marker for factors that will serve to predict poorer engagement in psychosocial interventions like PST.