Lack of Differential Symptom Change with Cognitive-Behavioral versus Light Therapy for Winter Depression: A Network Intervention Analysis

Background This study is a network intervention analysis comparing the symptomatic response of two first-line treatments for winter seasonal affective disorder (SAD): light therapy (LT) and group cognitive-behavioral therapy for SAD (CBT-SAD). Methods Scores on the Beck Depression Inventory-II at mid- and post-treatment on individual items and on four previously-identified symptom clusters were examined in SAD patients randomly assigned to receive LT ( n = 85) or CBT-SAD ( n = 74). Results No treatment differences in either individual symptoms or symptom cluster scores were observed. In both mid- and post-treatment networks, symptoms were primarily associated with each other within their respective, cognitive, vegetative, and affective domains (regardless of treatment). Results suggest that symptom network connections may weaken across treatment. Conclusions The lack of treatment differences indicates that these two mechanistically different treatments do not differ in effect on symptoms or symptom clusters. Future work should examine the association of treatment with symptom types over shorter time intervals.