Seasonal Mood Changes: Longer Days can be Good News

If you feel more energized as the days get longer, you're not the only one. When seasonal mood and energy changes are prominent enough they can be labeled with a diagnosis of Seasonal Affective Disorder (SAD), discovered by Dr. Norman Rosenthal after noticing that his own sluggish mood, first noticed after moving from sunny South Africa to New York, improved after exposing himself to bright light.

More sunlight can have positive effects for many with seasonal depression.

Source: R. Lavine

SAD has been diagnosed for people who become depressed, fatigued, and who sometimes gain weight with the onset of dark, shorter days in fall and winter, and then cheerful in spring and summer with the appearance of sunnier, longer days. These symptoms of SAD affect about 8 percent of people in wintry New Hampshire but much fewer, about 2 percent, in sunnier places like Florida.

Lack of sunlight may alter sleep-wake cycles by means of nerve signals from special nerve cells originating in the retina that act on the brain's biological clock (the suprachiasmatic nucleus) with the collaboration of melatonin from the pea-sized pineal gland. Appetite, energy, and mood can be affected as a result. According to the Mayo Clinic:

“although causes are unknown, some factors that may come into play include:

• Your biological clock (circadian rhythm). The reduced level of sunlight in fall and winter may cause winter-onset SAD. This decrease in sunlight may disrupt your body's internal clock and lead to feelings of depression.
• Serotonin levels. A drop in serotonin, a brain chemical (neurotransmitter) that affects mood, might play a role in SAD. Reduced sunlight can cause a drop in serotonin that may trigger depression.
• Melatonin levels. The change in season can disrupt the balance of the body's level of melatonin."

Special lights that imitate sunlight by providing high-intensity, full-spectrum lighting according to Dr. Rosenthal’s specifications, used for about 20 minutes a day, have helped. They are popular in Scandinavian countries faced with 9 months of darkness. Do not be fooled by cheaper imitations. In Norway, some classrooms feature all-around high-tech bright lighting carefully engineered to mimic the changing hues of a summer day. Icelanders, who, statistics show, have lower levels of SAD than North American locations at the same latitude and similarly long winters, have also claimed benefits from eating ocean fish like cod, salmon, or sardines, which contain high levels of omega-3 fatty acids, or from omega-3 supplements. Medications, psychotherapy, and other steps have also been helpful in treatment.

Similar seasonal changes have also been found in people with mood swings prominent enough to be diagnosed as bipolar disorder, where overly ebullient, risky behavior can alternate with periods of depression and sluggishness. These symptoms can vary in shades of grey from Bipolar I to a less prominent version called Bipolar II to an even milder form called cyclothymia or Bipolar III. Because of the wide range, some authors label these as Bipolar Spectrum Disorders and include SAD as a possible variant (Roecklein, K. and others, 2010). Seasonal changes in these mood changes in about 90 percent of patients involve the “winter blues” typical of SAD, but 10 percent have a reversed pattern of summer depression followed by wintertime cheer.

So as the days get longer, many people with seasonal mood changes can look forward to better times ahead, a smaller number may experience better times during winter, and both can explore preventative steps and treatment if needed.