A method for reducing one or more symptoms associated with seasonal affective disorder and/or seasonality in symptoms of bipolar and/or premenstrual syndrome in an individual, the method including administering to the individual suffering from seasonal affective disorder and/or more generally, seasonality symptoms, a composition that comprises a therapeutically effective amount of an agent to down regulate the activity of an orexin selected from the group consisting of orexin A or orexin B, at one or more orexin receptors.
