can you give me the signs that someone who is depressed might be thinking of doing something to hurt themselves?
Many Veterans don’t show any signs of an urge to harm themselves before doing so, but some may show signs of depression, anxiety, low self-esteem, or hopelessness.  They might also seem sad, depressed, or agitated most of the time.
and acting differently is a sign that something might be up?
Yes, they may change the way the act . They might start to do poorly in work or school and they might act violently or take risks