Young gay men are six times more likely than those over 45 to attempt suicide.
Experts say if the depression is left untreated, it can heighten the risk of another stroke.
Genes could make people more sensitive to their environment.
The research has been described as a game-changer in understanding the condition.
A major study has shown the real impact of depression on your overall physical health.
This could be the key to getting treatment to more people in need.