Researchers have found that your mood and personality may be influenced by something out of your control - your birthday.

A team of scientists from Semmelweis University in Hungary have found that when someone is born can play a role in their chance of developing a particular temperament or mood disorder. They recently presented their findings at the European College of Neuropsychopharmacology Congress in Germany. 

Previous research has shown that an individual's dopamine and serotonin levels - neurotransmitters that influence mood - can be affected by their season of birth. 

"This led us to believe that birth season may have a longer-lasting effect," said Xenia Gonda, pyschologist and lead researcher in a press release.

In the study, the researchers assessed the correlation between the birth season of participants and their personality traits in adulthood. The results showed that participants born in summer were more likely to have a cyclothymic temperament - rapid and frequent mood swings, than those born in winter. Those born in spring and summer were also more likely to possess a hyperthymic temperament - high levels of energy and positivity. 

The findings also revealed that participants born in autumn were less likely to be depressed than those born in winter, and those born in winter were less likely to have an irritable temperament than those born in the other seasons.  

"Temperaments are not disorders but biologically-driven behavioural 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," said Eduard Vieta from the European College of Neuropsychopharmacology, Barcelona, in a press release. 

The next step is to search for genetic markers which could give a better indication of the connection between birth season and mood disorders. If the mechanism is identified, there could be a scientific explanation to your astrology reading after all.

Source: EurekAlert