Very sad statistics. Often when people are rescued from a suicide attempt, they have strong regrets about their actions, and their life often improves from this low point. Which shows that suicide can be the result of a moment of madness brought on by a very dark mood.
These moods can be brought about by a chemical imbalance in the brain. The writer Ernest Hemingway committed suicide. His father, brother and sister did the same. It's thought that they suffered from a rare hereditary medical condition that can cause suicidal thoughts.