Professor Rory O'Connor, of Glasgow University, the new UK president of the International Academy of Suicide Prevention, said around one million people take their own lives each year.
He said the problem did not attract the same level of research funding as other killers such as heart disease, cancer and stroke.
"I am not saying do not fund those, but we really need much more attention on suicides," he said.
Professor O'Connor stressed suicide rates had fallen 18% in the last 10 years in Scotland amid a Scottish Government drive to tackle the problem. In England suicide rates have climbed during the same time frame.
However, Professor O'Connor said incidence of suicide was still higher in Scotland than England, with Scotland experiencing around 700 deaths a year. He said a "psychological autopsy" study, a detailed probe into the circumstances which precede suicides, may help explain why.
Professor O'Connor said: "Although it is great to see that the suicide rate has dropped markedly in recent years and there are a number of research initiatives in Scotland which are to be welcomed, we still know relatively little about why the suicide rate is so much higher in Scotland than it is in England."
He said while it is estimated 80-90% of those who kill themselves have a mental disorder, this did not explain why some people with mental health problems take their own lives while others do not.