Longitudinal associations between perceived stress and anhedonia during psychotherapy

Background Chronic stress alters reward sensitivity and contributes to the emergence of anhedonia. In clinical samples, the perception of stress is a strong predictor of anhedonia. While there is substantial evidence demonstrating psychotherapy reduces perceived stress, little is known regarding the effects of treatment-related decreases in perceived stress on anhedonia. Methods The current study investigated reciprocal relations between perceived stress and anhedonia using a cross-lagged panel model approach in a 15-week clinical trial examining the effects of Behavioral Activation Treatment for Anhedonia (BATA), a novel psychotherapy to treat anhedonia, compared to a Mindfulness-Based Cognitive Therapy (MBCT) comparison intervention ( ClinicalTrials.gov Identifiers NCT02874534 and NCT04036136 ). Results Treatment completers ( n =72) experienced significant reductions in anhedonia ( M =-8.94, SD =5.66) on the Snaith-Hamilton Pleasure Scale ( t (71)=13.39, p <.0001), and significant reductions in perceived stress ( M =-3.71, SD =3.88) on the Perceived Stress Scale ( t (71)=8.11, p <.0001) following treatment. Across all treatment-seeking participants ( n =87), a longitudinal autoregressive cross-lagged model revealed significant paths showing that higher levels of perceived stress at treatment Week 1 predicted reductions in anhedonia at treatment Week 4. Conclusions Longitudinal models illustrated that individuals with relatively high perceived stress at the start of treatment were likely to report relatively lower anhedonia a few weeks into treatment. At mid-treatment, individuals with low perceived stress were more likely to report lower anhedonia towards the end of treatment. Early treatment components are thought to reduce perceived stress, allowing for mid-to-late treatment components to exert their direct effects on anhedonia. The findings presented here demonstrate the importance of including stress-reducing components in cognitive-behavioral-based anhedonia treatments.