If you dream that you commit suicide, this suggests that conditions in your life are so frustrating that you are no longer willing to cope with a situation or relationship in the same way as you did in the past.
This dream can also mean you are having feelings of guilt and so you are turning the aggression on yourself through your dream. On a more positive note, a dream of committing suicide may suggest that you are saying good-bye to one aspect of yourself and becoming a renewed, better person.
If you see someone else commit suicide in your dream, you are feeling concerned for that person.
Also consider what characteristics and qualities in that person you may be trying to “kill” and annihilate in your own self. Perhaps you hope that you are not like that person in some way and are making attempts to get rid of those traits within your own self.