It is reported that an increased number of nightmares, statistically raises the number of suicides for people who are suicidal.
The correlation with dreams and real life is because dreams are most of the time projections of what we live through out the day or the thoughts we go to sleep with.
A disturbed mind, will end up seeing not so good dreams as the title implies. Also stress is a major factor.
if we go to bed stressed, we will not have a good nights sleep and will most probably suffer the side effects of stress even on our sleep.