news about melatonin
SAD? Help for the winter blues
17/01/2007When winter hits and the sun hides until spring, mental health professionals see an increase in the number of people with symptoms of depression.
Seasonal affective disorder (SAD) is thought to be a type of depression brought on by changing seasons and a shift in the body's internal clock. The most common type of SAD is winter depression. According to the American Psychiatric Association, the condition is more likely to be diagnosed in women than in men. Also, it usually starts in people older than 20 years of age. Because northern latitudes have colder weather and less sunlight during the winter months, people who live in the north are more likely to suffer from SAD.
Symptoms include:
• Fatigue
• Lack of interest in normal activities
• Social withdrawal
• Craving foods high in carbohydrates
• Weight gain
What causes SAD is not known for sure. However, researchers suspect decreased hours of sunlight plays a role. Dr. Alfred Lewy said disruptions in circadian rhythm, or the body's internal clock, are a main cause of the disorder. Many people have a hard time adjusting to waking up without bright sunlight to cue their body's dawn response.
For these patients, Lewy recommends bright light therapy. With scheduled exposures to a light box every morning when they wake up, patients can remind their body it's time to wake up and get their circadian rhythm back on track. Studies haven't been able to prove the light therapy provides more than a placebo effect, however. People with eye diseases should not use this therapy without consulting a doctor first.
Lewy said many SAD patients don't have the time to sit in front of a light box every morning. He's researching another way to get a delayed internal clock aligned. Melatonin may be a more practical treatment. Lewy and colleagues found in a recent study that afternoon melatonin doses helped patients better than placebo.
"If you take a tiny little dose of melatonin in the afternoon, it tricks the body into thinking it's dark out. It's a chemical dark signal," Lewy said.
This treatment is not perfected yet, however, and Lewy would not recommend patients try this until a company develops a sustained release formulation. Also, melatonin can make people very sleepy, which could increase the risk of an accident if they drive.