can psychedelic substance help people with mental illnesses?

1. can they help with addiction?

1.1. drinking addiction

1.2. smoking addiction

1.3. opiate addiction

2. Could they help someone with depression or an anxiety disorder/ phobia?

2.1. it could help give a person a new viewpoint on there situation

2.2. it may help a therapist learn about the person

3. It may help someone cope with a terminal illness.

3.1. it may help someone come to terms with there death?