Licensed therapists at the master's level do make diagnoses. I have a master's degree in mental health counseling and I am licensed as a clinical mental health counselor. We had detailed and specific training in diagnosis and testing as well as treatment of mental illness, even a class on psychopharmacology but we don't prescribe medication - would need to get an M.D., P.A., or A.P.R.N. to prescribe although in some states they have an advanced practice license for psychologists that allows them to prescribe.

Mental health counselors have the most training in diagnosis and assessment of other master's level therapists. Social workers might not have any classes in it unless they took them as electives. Their clinical training is not classroom-based. I had two and a half years of classes that covered everything that we do, and then a year of practicum and internship as a student, and then two more years of supervision while working as certified professional counselor intern before being licensed. By the time we finish the internships and supervision we have as much training and experience as entry-level doctoral level psychologists, just more of it is experiential as opposed to classroom and research.