Washington, Sept 9: Ever wondered why you feel dull and lacklustre during the winter season? Well, researchers at the Centre for Addiction and Mental Health (CAMH) have got the answer for your query.
The research team has identified the mechanism underlying seasonal mood changes, which can help explain the mood swing.
With the help of PET scans, the team led by Dr. Jeffrey Meyer have shown that the actions of the serotonin transporter-involved in regulating the mood-altering neurotransmitter serotonin-vary by season.
The team discovered that the serotonin transporter levels were significantly higher in all investigated brain regions in individuals studied in fall/winter, compared to those studied in spring/summer in a study of healthy subjects.
Also, the higher serotonin transporter binding values occurred at times when there is less sunlight.
The presence of higher serotonin transporter levels might explain why many people experience the onset of major depressive episodes in the fall and winter.
As Meyer explains, this is "an important lead in understanding how season changes serotonin levels.
"This offers an explanation for why some healthy people experience low mood and energy in the winter, and why there is a regular reoccurrence of depressive episodes in fall and winter in some vulnerable individuals.
"The next steps will be to understand what causes this change and how to interfere with it," he added.