The study, which examined 26,916 suicide cases, found that babies born in April, May or June had a 17% greater chance of killing themselves than those born in the autumn.
People born in these months are also more prone to alcoholism, depression, and mood disorders. The researchers suggested that the elevated suicide rates of spring and summer births reflect this.
The research team looked at data on all deaths from suicide and undetermined injuries between 1979 and 2001 in what they say is the largest study of any possible link to suicide of this kind.
The research, published in the British Journal of Psychiatry, stated, "Our results support the hypothesis that there is a seasonal effect in the monthly birth rates of people who kill themselves and that there is a disproportionate excess of such people born between late spring and midsummer compared with the other months."
The head of the research team, Dr. Emad Salib, consultant psychiatrist and senior lecturer at Liverpool University, says it may be that a person's health prospects are linked to his or her seasonal experiences in the womb.
"As the baby is developing the brain is very sensitive to any change in maternal state, like infections and even temperatures. This can affect the way that cells in the brain are arranged. We are born all the same but some of us are more vulnerable than others to certain diseases. Some of us will get away with it, but some of us may end up falling victim to disease and committing suicide," he says.
Dr. Mike McClure, suicide expert and director of public education at the Royal College of Psychiatrists said that the theory is plausible.
"This work looks at the possible biological factors," he says. "There may be some behavioral conditions that differ in the mother during the gestational period that influence the child. All sorts of things could be very different from a seasonal perspective and that could influence whether the child or adult is more likely to be susceptible to depression or alcoholism for example."
