Midday light new hope for bipolar disorder patients

Regular exposure to the bright white light at midday can significantly decrease symptoms of depression and increase functioning in people with bipolar disorder, reveals a new study. Bipolar disorder, also known as manic-depressive illness, is a brain disorder that causes unusual shifts in mood, energy and activity levels.

The findings showed that people exposed to bright white light between noon and 2:30 p.m. for six weeks experienced a significantly minimal depression rate and returned to normal functioning. Over 68 per cent of patients who received midday bright light achieved a normal level of mood, compared to 22.2 per cent of patients who received placebo light.

Further, bright light therapy also reduced the average depression score to 9.2 compared to 14.9 to those to the placebo group, the researchers said. "Effective treatments for bipolar depression are very limited," said lead author Dorothy Sit, Associate Professor at Northwestern University, Illinois in the US.

The light therapy, which also had minimal side effects, has conventionally been tested using morning light at awakening because previous research has suggested that morning light helps reset circadian rhythms and can be helpful in the treatment of SAD, Sit said.

However, the mechanism of response is unclear in bipolar disorder, he noted.