Psychotherapy can provide diagnosis using the DSM (Diagnostic & Statistical Manual). A primary focus of psychotherapy is the identification and diagnosis of mental disorders. Coaching does not diagnose.
Psychotherapy can provide diagnosis independent of the client’s self-assessment. This function is recognized by third parties such as the courts. Coaching, by way of contrast, relies on the client’s self-assessment.
Psychotherapy can use diagnosis to treat clinical disorders like anxiety and depression. Coaching does not treat, claim that it is treatment, or use the word treatment.
The types of goals are different, Psychotherapy goals typically involve treatment of a mental disorder by the therapist. Coaching goals typically focus on quality of life.
Who sets goals is different. In psychotherapy they may be set by the therapist after diagnosis. Goals in coaching are typically self-identified by the client.
Psychotherapy may be provided by primary caregivers such as hospitals. Coaching is rarely associated with primary care.
Coaches are required to refer clients to psychotherapists or psychiatrists if the client’s problem is outside their scope of practice. Psychotherapists are those to whom clients are referred.
Psychotherapy typically involves recognized power differentials between client and therapists. This vulnerability of clients gives psychotherapists legal and ethical responsibilities. Coaching is in the nature of a supportive peer-to-peer relationship, with the results evaluated by the client, and is designed to avoid these power differentials.
The focus of much psychotherapy is intervention by the therapist. The focus of much coaching is the teaching of self-help tools.