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S.A.D. Research

A pilot study of adherence with light treatment for seasonal affective disorder

Psychiatry Res. 2006 Dec 8;
A pilot study of adherence with light treatment for seasonal affective disorder.

Lam RW.

Department of Psychiatry, University of British Columbia, 2255 Wesbrook Mall Vancouver, BC, Canada V6T 2A1.

Non-adherence with antidepressant medication regimens is now recognised as a substantial problem when evaluating depression outcome. Given the behavioural demands of light treatment (LT), it might be expected that non-adherence would be even more pronounced in LT, a form of intervention for seasonal affective disorder (SAD). However, little research has focused upon the extent to which patients in light treatment protocols adhere to set regimens. Nineteen patients with SAD were allocated to either treatment with bright white light (intervention) or dim red light (control condition) in a four-week protocol. Light exposure was estimated automatically (without participants` knowledge) with elapsed time meters built into the light box. Daily diaries were also used to measure self-reported light box use. Participants were instructed to use the light box for 30 min each day during week 1, 45 during week 2 and one hour during weeks 3 and 4 (total duration of prescribed light exposure 1365 min). The results indicated that mean duration of light box operation for the entire sample was 59.3% of the prescribed 1365 min. Six of nineteen (31.6%) patients dropped out of treatment. Amongst those completing treatment, adherence to the prescribed duration of exposure averaged 83.3% (S.D.=31.4). A trend was found for the intervention condition to generate a lower dropout rate, as well as a trend for the degree of adherence to be greater in the intervention condition. Importantly, there was no association between adherence as measured automatically and the higher rates of self-reported adherence as measured in diaries. In summary, the results of this pilot study suggest that adherence with light treatment is of a similar order of magnitude to antidepressant medication adherence. Patient self-report was found to be unrelated to objectively estimated duration of light box use, a finding with significant research and clinical implications. Future research studies should routinely measure and evaluate adherence with light therapy and evidence-based techniques for maximising treatment adherence should be incorporated into routine clinical practice.

Quality of life as an outcome indicator in patients with seasonal affective disorder: results from the Can-SAD study.

Division of Clinical Neuroscience, Department of Psychiatry, University of British Columbia; Mood Disorders Centre, UBC Hospital, Vancouver, BC, Canada.

Background. Although a host of studies have now examined the relationship between quality of life (QoL) and non-seasonal depression, few have measured QoL in seasonal affective disorder (SAD). We report here on results from the Can-SAD trial, which assessed the impact of treatment with either antidepressant medication or light therapy upon QoL in patients diagnosed with SAD.Method. This Canadian double-blind, multicentre, randomized controlled trial included 96 patients who met strict diagnostic criteria for SAD. Eligible patients were randomized to 8 weeks of treatment with either: (1) 10000 lux light treatment and a placebo capsule or (2) 100 lux light treatment (placebo light) and 20 mg fluoxetine. QoL was measured with the Quality of Life Enjoyment and Satisfaction Questionnaire (Q-LES-Q) and the Medical Outcomes Study (MOS) Short-Form General Health Survey (SF-20) at baseline and 8 weeks.Results. Both intervention groups showed significant improvement in QoL over time with no significant differences being detected by treatment condition. Q-LES-Q scores increased significantly in seven of eight domains, with the average scores rising from 48.0 (S.D.=10.7) at baseline to 69.1 (S.D.=15.6) at week 8. Treatment-related improvement in QoL was strongly associated with improvement in depression symptoms.Discussion. Patients with SAD report markedly impaired QoL during the winter months. Treatment with light therapy or antidepressant medication is associated with equivalent marked improvement in perceived QoL. Studies of treatment interventions for SAD should routinely include broader indices of patient outcome, such as the assessment of psychosocial functioning or life quality.

O sweet spot where art thou? Light treatment of Seasonal Affective Disorder and the circadian time of sleep.

the circadian time of sleep.

Murray G, Michalak EE, Levitt AJ, Levitan RD, Enns MW, Morehouse R, Lam RW
Faculty of Life and Social Sciences, Swinburne University of Technology, PO Box 218 John St., Hawthorn 3122 Melbourne, Victoria, Australia. gwm@swin.edu.au

This study investigated Lewy`s Phase Shift Hypothesis (PSH) for winter Seasonal Affective Disorder, which asserts that the phase angle difference (PAD) between circadian and sleep rhythms is critical in the mechanism of light`s therapeutic action. Specifically, we sought to test whether a euthymic “sweet spot” could be identified at a PAD (between temperature minimum and wake time) of circa 3 h. After a baseline week, symptomatic SAD patients (N = 43) received 8 weeks of morning light treatment. Analyses were based on SIGH-SAD ratings made at baseline and posttreatment. Also estimated pre- and posttreatment were T(min) (calculated from an algorithm based on Morningness-Eveningness self-report scores), and the phase of the sleep-wake rhythm (as assessed by daily sleep logs). It was predicted that a quadratic relationship would exist between PAD and depression ratings at baseline and posttreatment, with lowest levels around PAD = 3 h. It was further predicted that shift towards PAD = 3 h with treatment would be associated with decreases in depression with treatment. Although trends were in the expected direction, none of the three predictions were supported. Findings are discussed in terms of the study`s limitations and the experimental challenge of parsing independent and interacting contributions of sleep and circadian phase.