New research shows that the season you are born has a significant impact on your risk of developing mood disorders. People born at certain times of year may have a greater chance of developing certain types of affective temperaments, which in turn can lead to mood disorders (affective disorders). This work is being presented at the European College of CNP Congress in Berlin.

Seasons of birth have traditionally been associated with certain personality traits, such as novelty seeking, and various folklore justifications, such as astrology, have sought to explain these associations. Now a group of researchers from Budapest, Hungary, are presenting a study which links birth season with temperament.

According to lead researcher, Assistant Professor Xenia Gonda, "Biochemical studies have shown that the season in which you are born has an influence on certain monoamine neurotransmitters, such as dopamine and serotonin, which is detectable even in adult life. This led us to believe that birth season may have a longer-lasting effect. Our work looked at over 400 subjects and matched their birth season to personality types in later life. Basically, it seems that when you are born may increase or decrease your chance of developing certain mood disorders."

"We can't yet say anything about the mechanisms involved. What we are now looking at is to see if there are genetic markers which are related to season of birth and mood disorder."

The group found the following statistically significant trends:

· cyclothymic temperament (characterized by rapid, frequent swings between sad and cheerful moods), is significantly higher in those born in the summer, in comparison with those born in the winter.

· Hyperthymic temperament -- a tendency to be excessively positive -- were significantly higher in those born in spring and summer.

· Those born in the winter were significantly less prone to irritable temperament than those born at other times of the year.

· Those born in autumn show a significantly lower tendency to depressive temperament than those born in winter.

Commenting for the European College of Neuropsychopharmacology, Professor Eduard Vieta (Barcelona) XY said: "Seasons affect our mood and behavior. Even the season at our birth may influence our subsequent risk for developing certain medical conditions, including some mental disorders. What's new from this group of researchers is the influence of season at birth and temperament. Temperaments are not disorders but biologically-driven behavioral and emotional trends. Although both genetic and environmental factors are involved in one's temperament, now we know that the season at birth plays a role too. And the finding of "high mood" tendency (hyperthymic temperament) for those born in summer is quite intriguing."