A reader asks:

 I have at least some degree of depression on a year-round basis with a worsening in the winter months. In the past, I’ve responded very well to treatment consisting of continuous antidepressant medication and the addition of light therapy in the winter. I’m about to start my light treatment for the winter, however, this year, my symptoms feel a bit different from previous winters: on top of the usual depression, I also feel anxious and edgy. Will my light box help the anxiety too? From reading your site, I’ve seen that some people get agitated as a side-effect of using their light boxes, and although that hasn’t happened to me in the past, I certainly don’t want to feel more tense than I do now. Thanks for any guidance you can provide.

Answer:

Although SAD is often characterized as a “lethargic” depression, in fact, anxiety symptoms are present in a majority of cases. Your case is more complicated in that previous winters were without such symptoms, and your case is not simple SAD. Light therapy elicits anxiety symptoms only in a small proportion of patients; in most cases, patients find it energizing yet calming (not really a contradiction in terms!). When anxiety symptoms occur as a side effect, this is almost always a sign of “overdose” that is correctible by reducing intensity or exposure duration or scheduling the lights later in the morning. Clinical guidance and monitoring are a sine qua non. Also, keep in mind that although anxiety symptoms are often secondary to depression, an anxiety disorder can be primary, in which case we do not recommend light therapy.