Methods and devices are described that use one or more thermally responsive current-controlling elements to regulate current flow to an electrical component, particularly a light source such as an LED. Examples of such thermally responsive current-controlling elements include thermistors, inductors, and capacitors. for treating conditions or disorders which can be alleviated by reducing food intake are disclosed which comprise administration of an effective amount of a purine analog, alone or in conjunction with other compounds or compositions that affect satiety. The methods are useful for treating conditions or disorders wherein appetite reduction would be beneficial, including obesity and binge-eating disorder. Pharmaceutical compositions for use in the methods of the invention are also disclosed.