The authors identified a patient who had premenstrual syndrome (late
luteal phase dysphoric disorder) only in the fall and winter and was
virtually asymptomatic during the spring and summer. On the basis of
previous experience with seasonal affective disorder, they treated the
patient with bright artificial light, which reversed her symptoms. On
subsequent occasions they reversed this treatment effect with oral
melatonin administration and found that propranolol and atenolol, beta-
antagonists that inhibit the production of melatonin, had a therapeutic
effect similar to that of light. They discuss the implications of these
findings in relation to the importance of melatonin as a mediator of
seasonal rhythms in biology.Abstract Teaser