There seems to be some confusion between the clinical and coding definitions of "med management". From a coding perspective "med management" is done by the MD (psychiatrist) and the correct code is 90862. (90862 Pharmacologic management, including prescription, use, and review of medication with no more than minimal medical psychotherapy) This involves minimal therapy and is not a time base code.
However, many clinical practices view "med management" as a “15 minute appt” and code it as one of the psychotherapy with E/M codes. (e.g. 90805, 90807, 90809 Individual psychotherapy, insight oriented, behavior modifying and/or supportive, in an office or outpatient facility… with medical evaluation and management services)
In my experience working with both the clinical and coding perspectives, I've found this situation is usually a psychotherapy session with the psychologist and med management (90862) by the psychiatrist. If this is the situation, both services are billable according to the NCCI.
If both psychotherapy and psychotherapy with E/M are providing, they are not separately billable. From a coding perspective, the psychotherapy session is a component of the psychotherapy w/ E/M session. From a clinical perspective, there is a medical necessity concern. However, there are times, when the services may be medical necessary. I would suggest a call to the payer to explain the medical necessity and good documentation should help. I hope this is helpful.