Once regarded skeptically by the experts, seasonal affective disorder is now well established. Epidemiological studies estimate that its prevalence in the adult population of the US ranges from 1.4 percent (Florida) to 9.7 percent (New Hampshire).
Light Therapy for Seasonal Affective Disorder
The US National Library of Medicine notes that "some people experience a serious mood change when the seasons change. They may sleep too much, have little energy, and may also feel depressed. Though symptoms can be severe, they usually clear up."[4] The condition in the summer is often referred to as reverse seasonal affective disorder, and can also include heightened anxiety.
SAD was first formally described and named in 1984 by Norman E. Rosenthal and colleagues at the National Institute of Mental Health.
There are many different treatments for classic (winter-based) seasonal affective disorder, including light therapy with sunlight or bright lights, antidepressant medication, cognitive-behavioral therapy, ionized-air administration, and carefully timed supplementation of the hormone melatonin.
Bright light therapy is effective with the patient sitting a prescribed distance, commonly 30–60 cm, in front of the box with her/his eyes open but not staring at the light source for 30–60 minutes. A 1995 study showed that green light therapy at doses of 350 lux produces melatonin suppression and phase shifts equivalent to 10,000 lux bright light therapy in winter depressives. A study published in May 2010 suggests that the blue light often used for SAD treatment should perhaps be replaced by green or white illumination. Discovering the best schedule is essential. One study has shown that up to 69% of patients find lightbox treatment inconvenient and as many as 19% stop use because of this.
Light Therapy for Seasonal Affective Disorder
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