What are the warning signs of when you need more than a psychologist when a doctor can prescrib, does it work by having psychologist and psychiatrist ?

Little improvement: When you are not getting better, you need to question the quality of the relationship with your therapist and if your therapist is helping you to achieve goals. Also frequently medication plus therapy is needed.

Meds and therapy : Optimally, it's a combination of medication and psychotherapy together that works best for alleviating mental health stress. Get a psychiatric evaluation for whatever it is that bothers you, and then find a reputable psychotherapist to help you deal with those issues. Per the psychiatrist, medications may or may not be necessary.