From a health point of view, how many sets are suggested when strength training?

Strengh training depends on how much you can take or what is your goal. It doesn't have to be really heavy or too many sets, it just have to be consistent and performed properly. More importantly do not try to compete with other people.

Major sources of stress, such as a death or divorce, problems in family relationships, job loss, school, and substance abuse, can trigger or aggravate some mental disorders in some people. but not everyone who goes through those things develops a mental illness