And I agree with many of them. They do have poor self-esteem.
Most have used drugs much of their lives. Many of them have been in jail or institutions for years. Some have been homeless and never had a steady job. Some have never paid child support. Or learned a trade. Not a lot to feel good about.
So what to tell them? How to help them feel better about themselves?
My approach is usually to tell them to start with little things. Go to work every day. Make your bed and put your living space in order each morning.
Take care of your health. See the doctor for regular checkups. Start a fitness program. Quit eating fast food.
Go to meetings and help out. Get a sponsor. Start being an example to younger addicts and alcoholics who need a role model.
If you don't have an education start out with getting a G.E.D.
Start changing these external behaviors and how you feel about yourself will change. Guaranteed.