I would sooner trust a psychiatrist to diagnose, or to confirm/deny a diagnosis made by a therapist. In some states, therapists have minimal training. (It's sometimes scary how little training they have to meet state licensing requirements.)

Therapists and psychiatrists don't always agree on the diagnosis(es); this is reported quite often.

Most psychiatrists will take some input from therapists on diagnosis(es); yet, they will go by their own expertise.

Neuropsychologists are very helpful in diagnosing. If a psychiatrist is having trouble with diagnosis(es), they often refer for neuropsych testing.

If you are only seeing a therapist, your diagnosis is then made by the therapist alone, unless consults are requested of a psychiatrist or a neuropsychologist.

I hope this helps.

WC