Cognitive Change Across Cognitive-Behavioral and Light Therapy Treatments for Seasonal Affective Disorder: What Accounts for Clinical Status the Next Winter?

Abstract

Efficacious treatments for seasonal affective disorder include light therapy and a seasonal affective disorder-tailored form of cognitive-behavioral therapy. Using data from a parent clinical trial, these secondary analyses examined the relationship between cognitive change over treatment with cognitive-behavioral therapy, light therapy, or combination treatment and mood outcomes the next winter. Sixty-nine participants were randomly assigned to 6-weeks of cognitive-behavioral therapy, light therapy, or combination treatment. Cognitive constructs (i.e., dysfunctional attitudes, negative automatic thoughts, and rumination) were assessed at pre- and post-treatment. Dysfunctional attitudes, negative automatic thoughts, and rumination improved over acute treatment, regardless of modality; however, in participants randomized to solo cognitive-behavioral therapy, a greater degree of improvement in dysfunctional attitudes and automatic thoughts was uniquely associated with less severe depressive symptoms the next winter. Change in maladaptive thoughts during acute treatment appears mechanistic of solo cognitive-behavioral therapy’s enduring effects the next winter, but is simply a consequence of diminished depression in light therapy and combination treatment.

It's complicated: The relation between cognitive change procedures, cognitive change, and symptom change in cognitive therapy for depression

“…As a way of integrating these seemingly disparate findings, it may be that the measurement of self-reported cognitive change in CBTs captures change in cognitive vulnerabilities whereas in treatment with somatic therapies, measurements of cognitive change capture the deactivation of state-dependent negative cognitions. (For a similar argument, see Evans et al, 2013). This hypothesis is endorsed by Garratt et al (2007), who conclude that "evidence suggests that cognitive changes associated with pharmacotherapy are more superficial than those associated with cognitive therapy" (p. 224).…”

“…Quilty, McBride, and Bagby (2008) reached a similar conclusion from an investigation in which they used structural equation modeling to characterize pre-to post-treatment changes in cognitions and symptoms, although cognitive change and symptom change was measured concurrently. In a study of seasonal affective depression, Evans et al (2013) reported that in CBT, but not in light therapy, cognitive changes during 6 weeks of treatment predicted depressive symptoms at 1-year winter follow-up. In contrast to the three studies just cited, each of which found specificity in the relation between cognitive change and symptom change, Segal and colleagues reported that cognitive reactivity predicted depressive relapse irrespective of whether it followed from treatment with CT or antidepressant medications (Segal et al, 1999(Segal et al, , 2006.…”

“…Position 3: the role of cognitive change as a mediator of symptom change is specific to cognitive procedures (X, X, 0, +1) Finally, it is possible that cognitive change functions as a mediator of symptom change only when it occurs in the context of a treatment that emphasizes cognitive change procedures. Although there is evidence that cognitive change is associated with symptom change in CBT, IPT, and PST, there is also some evidence that this association is not found in somatic therapies (i.e., light therapy and antidepressants; Evans et al, 2013;Quilty et al, 2008) or in ACT (Forman et al, 2007(Forman et al, , 2012. Thus, the position that cognitive change is a specific mediator has some support.…”

“…In investigations of the effects of cognitive procedures on cognitive change and symptom change in depression, very few studies have included tests of all four of the relationships described above while also attempting to rule out reverse causality and third variable confounds (e. g., Evans et al, 2013;Kuyken et al, 2010) and only one of these included a test of mediation (Kuyken et al). Other investigations have included tests of all four relationships without including using methods that address these confounds (see Kazdin, 2007).…”

Bright light therapy in the treatment of patients with bipolar disorder: A systematic review and meta-analysis

“…Bright light therapy (BLT), also called phototherapy, refers to the use of glare therapy to treat depressive symptoms [24], BLT was originally used to treat patients with seasonal affective disorder [25][26][27][28][29]. Numerous studies indicate direct and indirect effects of light on mood.…”