Fall is a time of low energy and mood for millions of people. The shorter daylight hours can signal chemical changes in the brain that cause symptoms of Seasonal Affective Disorder (SAD) and the milder "Winter Blues" — changes in eating and sleeping habits, loss of energy, concentration and sex drive, and depression.

Symptoms usually begin in early or late fall and subside by April. In Winter Blues, symptoms may be barely noticeable, but for those most seriously affected, symptoms cause difficulties in all aspects of their lives — fitness level, love life, career advancement and family life. Typical symptoms include:

• excessive tiredness

• sleepiness

• trouble awakening in the morning

• cravings for foods rich in carbohydrates

• weight gain, shed easily in the spring

• withdrawal from friends and loved ones

• loss of self-esteem

• difficulty concentrating or performing routine tasks

• loss of sex drive

• feelings of hopelessness, and/or suicidal thoughts

Among the treatment for this disorder is phototherapy, or "light therapy." It involves exposing people to bright light — 10 to 20 times brighter than normal indoor light — for brief periods (15 to 30 minutes) each day. Phototherapy is believed to be more effective when begun before, not after, symptom outset, and is said to be effective in more than 75 percent of SAD patients. Free SAD information is available by calling 1-888-SAD-AWAY.