Components of Behavioral Activation Therapy for Depression Engage Specific Reinforcement Learning Mechanisms in a Pilot Study

Abstract

Background: Behavioral activation is an evidence-based treatment for depression. Theoretical considerations suggest that treatment response depends on reinforcement learning mechanisms. However, which reinforcement learning mechanisms are engaged by and mediate the therapeutic effect of behavioral activation remains only partially understood, and there are no procedures to measure such mechanisms.Objective: To perform a pilot study to examine whether reinforcement learning processes measured through tasks or self-report are related to treatment response to behavioral activation. Method:The pilot study enrolled 13 outpatients (12 completers) with major depressive disorder, from July of 2018 through February of 2019, into a nine-week trial with BA. Psychiatric evaluations, decision-making tests and self-reported reward experience and anticipations were acquired before, during and after the treatment. Task and self-report data were analysed by using reinforcement-learning models. Inferred parameters were related to measures of depression severity through linear mixed effects models.Results: Treatment effects during different phases of the therapy were captured by specific decision-making processes in the task. During the weeks focusing on the active pursuit of reward, treatment effects were more pronounced amongst those individuals who showed an increase in Pavlovian appetitive influence. During the weeks focusing on the avoidance of punishments, treatment responses were more pronounced in those individuals who showed an increase in Pavlovian avoidance. Self-reported anticipation of reinforcement changed according to formal RL rules. Individual differences in the extent to which learning followed RL rules related to changes in anhedonia.*Author affiliations can be found in the back matter of this article 239 Huys et al.

Different components of cognitive-behavioral therapy affect specific cognitive mechanisms

“…In theory, acting according to a predetermined plan could boost activity levels either by making potential rewards more salient (increasing reward sensitivity) or by lowering the perceived level of effort required (decreasing effort sensitivity), when deciding if a particular action is worth taking ( Fig. 1C ) ( 9 , 10 ).…”

“…3 ). Significantly, this change in decision-making was accompanied by an increased sense of achievement for actions and experienced pleasure for rewards, suggesting not only that goal setting decreased subjective weighting of effort but also that the resulting energizing of overall action levels may be sufficient to kick-start a positive reinforcement cycle through which behavioral activation therapy is thought to improve mood ( 10 , 33 ). This implies that a focus on setting achievable goals (which are gradually increased over time) and active monitoring of completion of activities (e.g., via monitoring forms) may be key active ingredients of behavioral activation therapy.…”

Different components of cognitive-behavioural therapy affect specific cognitive mechanisms

“…Model-based analysis revealed that this was due a selective reduction in sensitivity to required effort levels (but not sensitivity to potential rewards), when deciding how to act (Figure 4). Significantly, this change in decisionmaking was was accompanied by an increased sense of achievement for actions and experienced pleasure for rewards -suggesting not only that goal-setting decreased subjective weighting of effort but that the resulting energizing of overall action levels may be sufficient to kick-start a positive reinforcement cycle through which behavioural activation therapy is thought to improve mood (Quigley and Dobson, 2017;Huys et al, 2022). This implies that a focus on setting achievable rewards (which are gradually increased over time), and active monitoring of completion of activities (e.g., via monitoring forms) may be key active ingredients of behavioural activation therapy.…”

“…Acting according to a plan, rather than relying on internal state or mood, is thought to increase the likelihood of both acting and subsequently experiencing natural rewards, resulting in a positive reinforcement loop that serves to promote further activity and reward experience (Quigley and Dobson, 2017). In theory, acting according to a predetermined plan could boost activity levels either by making potential rewards more salient (increasing reward sensitivity), or by lowering the perceived level of effort required (decreasing effort sensitivity), when deciding if a particular action is worth taking (Reiter et al, 2021;Huys et al, 2022) (Figure 1c).…”

“…Such insight is vital, as understanding the mechanisms underlying treatment response is one of the most promising routes to achieving many of the goals of mental health research -including increasing efficacy, engagement, and, ideally, theoretically-information treatment personalization (Huibers et al, 2021). Here, we argue that developments in the cognitive sciences concerning how to use robustlydesigned behavioural tasks, in combination with rigorous modelling procedures that generate precise and reliable measures of cognitive processes, can accelerate progress towards these goals (Reiter et al, 2021;Huys et al, 2022).…”