A reader asks:

 Can you tell me if sunbeds help in treatment of seasonal affective disorder?

Answer:

The provisional, but strong answer is No! The essence of light therapy is enhanced illumination of the eyes at appropriate intensity, duration and time of day. The essence of sunbed use is ultraviolet radiation of the skin, with the eyes covered. Apart from no demonstration of efficacy as an antidepressant, the consensus of dermatologists is that use of sunbeds should be avoided altogether to avoid risk of skin cancer. Don’t let suntan parlors tell you otherwise.