NEURAL REACTIVITY TO REWARD AS A PREDICTOR OF COGNITIVE BEHAVIORAL THERAPY RESPONSE IN ANXIETY AND DEPRESSION

Abstract

Background: Cognitive behavioral therapy (CBT) is a well-established treatment for anxiety and depression; however, response to CBT is heterogeneous across patients and many remain symptomatic after therapy, raising the need to identify prospective predictors for treatment planning. Altered neural processing of reward has been implicated in both depression and anxiety, and improving hedonic capacity is a goal of CBT. However, little is known about how neural response to reward relates to CBT outcomes in depression and anxiety. The current study used the reward positivity (RewP) event-related potential (ERP) component to examine whether neural reactivity to reward would predict CBT response in a sample of patients with anxiety without depression (n = 30) and comorbid anxiety and depression (CAD, n = 22).

Methods: Participants completed a guessing reward ERP paradigm before completing 12 weeks of standard CBT.

Results: The majority of the sample (68%; 35 out of 52 patients) responded to treatment, and those with a reduced RewP at baseline were more likely to respond to treatment. A reduced RewP was also associated with a greater pre-to-post CBT reduction in depressive symptoms among individuals with CAD, but not among individuals with pure anxiety.

Conclusions: CBT may be most beneficial in reducing depressive symptoms for individuals who demonstrate decreased reward reactivity prior to treatment. CBT may target reward brain function, leading to greater improvement in symptoms. These effects may be strongest, and therefore most meaningful, for individuals with reward-processing deficits prior to treatment.

Keywords: anxiety; cognitive behavioral therapy; depression; event-related potentials; reward.

Figure 1

Design of the guessing reward task. The task comprised 60 trials (15 win, 15 loss, 15 no-win and 15 no-loss), each consisting of a decision period, anticipation period, and outcome period, separated by an inter-trial interval ranging between 4–7 sec.

Figure 2

ERPs (negative up) across frontal electrode sites (AF3, AF4, Fz) in response to wins and breaking even, and scalp distributions depicting the win minus even difference (reward positivity, RewP) from 230–300ms.

Figure 3

Scalp distributions depicting the win minus even difference (reward positivity, RewP) from 230–300ms among CBT Responders and Non-Responders. Patients were considered to be ‘Responders’ if they received a 1 or 2 on the Clinical Global Impression Rating Scale, and ‘Non-Responders’ if their score was greater than 2. Responders to CBT exhibited less activation in response to reward, relative to the non-responders.

Figure 4

Scatter plot depicting the association between depressive symptoms, measured via the BDI (controlling for pre-treatment BDI), following CBT and the RewP among individuals with comorbid anxiety and depression. A smaller RewP at baseline was associated with lower depressive symptoms following CBT.