Finding the best therapy for SAD

Seasonal affective disorder (SAD) is a form of severe depression that occurs in autumn and winter. Two of the most popular forms of therapy for it are cognitive behaviour therapy (CBT) and light therapy in which sufferers sit in front of a light box that produces an artificial version of sunlight. Kelly Rohan from the University of Vermont looked into the long-term effectiveness of these treatments comparing those treated with light therapy, those treated with CBT, those treated with a combination of the two techniques and people on a waiting list for treatment. Rohan's study looked into how people were doing a year after their treatment. She found that the combination group did best with only 5.5% having a recurrence of their depression. 7% of those treated with CBT suffered a recurrence compared to 36.7% of those treated with light therapy. The recurrence of depression was also less severe in those with CBT than in the other groups. Previous studies have shown that light therapy is very effective so it is not so much that it does not work, rather that, left to their own devices, people find it hard to make time for a daily, half-hour session in front of a light box.

You can find out more about this research at

http://www.sciencedaily.com/releases/2009/10/091016163659.htm

Darkness, depression and dimming brainpower

It is known that lack of sunlight can contribute to depression but new research suggests that it might also have an effect on brainpower - at least for people suffering from depression. Shia Kent from the University of Birmingham in Alabama used data from another study covering 14,474 people to look at the links between depression, cognitive power and sunlight. They found that among the participants with depression low exposure to sunlight was associated with a significantly higher probability of cognitive impairment as assessed by short-term recall and temporal orientation. As well as regulating the hormones serotonin and melatonin light has also been shown to affect the flow of blood to the brain, something that has been linked with cognitive functioning.

You can find out more about this research at

http://www.sciencedaily.com/releases/2009/07/090727191728.htm

Genetic link for SAD

Past research has shown that seasonal affective disorder (SAD) tends to run in families. Researchers at the Uniformed Services University in Bethesda, Maryland, looked into the links between SAD and variations in genes responsible for the production of a hormone called melanopsin, which is produced in response to light and affects the body clock. The researchers found that people with SAD were more than five times as likely to have a particular variation of a gene called P10L responsible for the production of melanopsin.

You can find out more about this research at

http://www.mentalhelp.net/poc/view_doc.php?type=news&id=114464&cn=5

Brain chemistry of seasonal affective disorder

Seasonal affective disorder is a mood disorder which occurs in winter and is linked to a lack of energy, fatigue, overeating and a tendency to sleep longer as well as depressed mood. Researchers at the University of Toronto in Canada looked into the links between the seasons and the levels of a serotonin transporter in the brain. The serotonin transporter 'mops up' serotonin in the brain leading to reduced levels of serotonin, the brain's 'feel-good' chemical so the higher the levels of serotonin transporter the higher the risk of depression. The researchers found that the serotonin transporter was significantly more active in the autumn and winter and believe that light may have a direct effect on the activity of the protein. The study was based on brain scans of 88 volunteers carried out between 1999 and 2003.

You can find out more about this research at

http://news.bbc.co.uk/1/hi/health/7591342.stm

Seasonal depression and cognition

Seasonal affective disorder (SAD) is a mood disorder in which people's depression has a clear, seasonal pattern, usually coming on in the winter months. It is though to affect at least 5% of the population and between 60 and 90% of sufferers are women. It shares many of the symptoms of non-seasonal depression such as depressed, despairing or irritable mood, loss of interest in life, feelings of worthlessness, excessive or inappropriate guilt, low self-esteem, indecisiveness, diminished ability to think or concentrate and inability to experience pleasure. However, while conventional depression usually produces loss of appetite, weight loss and insomnia, seasonal depression usually leads to craving for carbohydrates, weight gain and sleepiness. Depression can also affect people's thinking leading to deficits in verbal fluency, visual search, psychomotor speed, attention and working memory but it is not known if seasonal depression has a similar effect on people's cognitive powers. A U.S. study of 93 people found that SAD was highly prevalent (28%) compared to 8.6% for conventional depression. More women than men were affected by SAD and both SAD and depression were associated with higher rates of cognition problems in comparison to people with no affective symptoms.

Sullivan, Brianna and Payne, Tabitha W. - Affective disorders and cognitive failures : a comparison of seasonal and nonseasonal depression American Journal of Psychiatry November 2007, 164(11), 1663-1667