Abstract

Objective
In process-outcome research, there is a growing body of literature investigating the therapeutic mechanisms underlying the promotion of positive change. This study investigated the between- and within-patient effects of problem mastery and motivational clarification on outcome in patients receiving two variations of cognitive therapies for depression.

Methods
This study drew on data of a randomized controlled trial conducted at an outpatient clinic and included 140 patients randomly assigned to 22 sessions of either cognitive-behavioral therapy or exposure-based cognitive therapy. To address the nested structure of the data and analyze mechanism effects, we used multilevel dynamic structural equations models.

Results
We found significant within-patient effects of both problem mastery and motivational clarification on subsequent outcome.

Conclusion
The results suggest that changes in problem mastery and motivational clarification precede symptom improvement during cognitive therapy for depressed patients and thus there may be benefit in fostering these putative mechanisms during psychotherapy.

Introduction

     Several evidence-based treatments have shown to effectively treat major depressive disorders (MDD) (Barkham & Lambert, 2021; Cuijpers et al., 2014, 2020). Each of these therapies is assumed to work according to specific change mechanisms.

     For instance, it has been hypothesized that cognitive-behavioral therapy’s (CBT) effects on depression can be explained by several putative change mechanisms with partial empirical evidence supporting them (for an extensive review see Crits-Christoph & Connolly Gibbons, 2021). A systematic review showed that cognitive change in CBT for depressive disorders was associated with changes in depressive symptoms, although the specificity of cognitive change as a mediator of CBT effects was not supported (Garratt & Ingram, 2007). Similarly, a meta-analysis found that patients participating in CBT differed significantly in post-treatment dysfunctional thinking from patients of control groups but not from patients in other forms of therapy (Cristea et al., 2015). Additionally, some studies have shown that in the treatment of depression improvements in compensatory skills were related to CBT outcome (Barber & DeRubeis, 2001; Connolly Gibbons et al., 2009; Strunk et al., 2007). Furthermore, a study supported the specificity of this mechanism for CBT (i.e., in terms of mediation effects) when compared with psychodynamic therapy (Crits-Christoph et al., 2017). Finally, studies have shown that in CBT for depression enhancing behavioral activation (Christopher et al., 2009) and environmental rewards (Gawrysiak et al., 2009) were associated with changes in depressive symptoms, with one study supporting them as mediators of CBT effects when compared to treatment-as-usual (Dimidjian et al., 2017).

Results

     At session 1, patients’ mean level of WHO-5 was 1.35 (SD = 0.76). In the BPSR-T, at session 1 the therapist had an average mastery score of 2.03 (SD = 0.85) and an average clarification score of 2.68 (SD = 0.89). Across all sessions of treatment, the average level of WHO-5 was 2.07 (SD = 1.04). Additionally, during the whole therapy, the average level of mastery was 3.43 (SD = 1.10), while the average level of clarification was 3.62 (SD = 0.85). During treatment, the correlation between mastery and clarification was r = 0.42 (p < .001). Furthermore, the correlation between mastery and the WHO-5 was r = 0.19 (p < .001) and between clarification and the WHO-5 was r = 0.11 (p < .001).