Commonly depressive symptoms are more pronounced in January and usually improve by the middle of the spring season. SAD tends to begin in the late teen years and comes back every year under similar weather circumstances. Effective treatments include photo-therapy, usually in the morning with bright-light therapy using commercially available light boxes. Taking a walk early in the morning may be beneficial. Anti-depressants may be required in patients unresponsive to light therapy. For people who are able to do it, moving to southern latitudes, where days are longer in the winter, may be of help.
Holiday Blues should not be confused with SAD. Although symptoms of holiday depression are similar to the ones of SAD, ie: increase or decrease in sleepiness, increase or decrease in appetite, decreased sex drive and energy, anxiety, diminished concentration and headaches; those symptoms are of lesser intensity and duration. Usually, when people return to their normal daily activities after the holidays are over the symptoms remit. If no remission in symptoms occur, a consultation with a therapist is required.
Schizophrenia and Manic Depressive Illness
Of interest is a report of the birth seasonality of individuals who develop schizophrenia and/or manic-depressive illness. Torrey EF and collaboration published a review of the literature in Schizophrenia Research 1997, which indicated in more than 250 studies covering 29 northern and 5 southern hemisphere countries that, "the studies are remarkably consistent in showing a 5-8% winter excess of births for schizophrenia and mania/bipolar disorder".
Agitation and Aggression
It has been noted that agitation and aggression are increased when temperatures are elevated above 90°F From "The Consultant Pharmacist" Nov 1999.
Weather and Neurological Disorders
Intriguing research performed by Torrey EF et. al. of the Stanley Foundation Research Programs, National Institute on Alcohol Abuse and Alcoholism, found a relationship between seasonal birth patterns of neurological disorders. Epilepsy appears to have the most consistent pattern, with excess of births in winter with a deficit of births in September.
Multiple Sclerosis, amyotrophic lateral sclerosis, and possibly Parkinson's disease appear to have an excess of spring births. Studies of cerebral palsy are not conclusive, although there are suggestions that there may be an excess of summer births.