Light Therapy: Therapeutic Potential for the Management of Depression in Primary Care

The management of depression utilises both pharmacological and non-pharmacological strategies. A recent meta-analysis has demonstrated that light therapy (LT) is effective in thetreatment of non-seasonal depression (NSAD). However, there is a paucity of evidence exploring itseffectiveness in those using LT in their own homes. The aim of this thesis is to design a randomised controlled trial to test the effectiveness of LT in Primary Care. A literature search was conducted from which options for key aspects of the study design wereidentified. This included eligibility criteria, duration of study, time of day and duration of light therapy use, feasibility of monitoring requirements and timing of saliva samples, perceived effectiveness of LT, and preference for the appearance of the LT device including both its size and the colour of light. Exploratory qualitative studies were undertaken, with stake-holders (GPs and the general public) to explore their awareness of LT, their views and opinions on the effectiveness, safety and feasibility of LT in the management of depression, and the aspects described above of theproposed study protocol. Strategies for recruitment of participants and use of incentives were also explored. Thirteen people, with experience of depression, participated in two focus group discussions. Awareness of the use of LT was mostly in relation to treatment of Seasonal Affective Disorder (SAD). No-one had used LT themselves, although some knew of others who had tried it. Generally, it was perceived as being suitable as an adjuvant therapy. It was considered to be safe as it was ‘natural’and had an ‘external action’, although misconceptions relating to tanning of the skin were held. Participants considered that the study design would be feasible to adhere to. Their preferred device distributed the brightest white light. However, they were open to using red light if they were told it would work. Participants suggested recruitment via routes other than through the GP, and advised that financial incentives to take part in the study were not required. They perceived participation in a trial as being a reward in itself. Five interviews were carried out with GPs. Most related LT use to treatment of SAD and were cautiously optimistic in their expectations of its effectiveness in NSAD, although all emphasised that there was currently a lack of evidence to support its use for this indication. They had negligible concerns regarding its safety. There was a clear need for something to offer patients with mild depression who had persistent symptoms and it was thought that, if the evidence was there to support it, light therapy could fill this need. The GPs main concern regarding the proposed study was maintaining confidentiality of participants and that participants themselves would not be ableto adhere to the LT regimen. They were supportive of the proposed study and were happy to support recruitment into it. As a result of these exploratory studies a trial protocol was developed. The procedure for recruitment of participants, eligibility criteria, LT dosing regimen, and choice of placebo were all influenced by this approach. Feedback from the focus group also lead to additional information, for example relating to side-effects, and effectiveness of different light therapy colours being added tothe Patient Information leaflets. The study has been submitted to, and received approval from, NHSResearch Ethics Committee and the relevant NHS Research Governance approval has been granted.