Your CBT therapist can work effectively in partnership with your GP, and with other doctors and professionals.
If you are receiving another “talking therapy”, like counselling or another form of psychotherapy, then it is unusual to receive CBT at the same time. This is because these therapies involve you in a similar way, so they might be less effective if you have them together.
If you are receiving some other form of treatment, such as prescription drugs, then you may be able to benefit from CBT at the same time. Your CBT therapist and your doctor usually work together. For example, as CBT starts to take effect, your doctor might gradually decrease the dose of drugs that you receive. You should not stop taking any drugs you have been prescribed just because you plan to have CBT.
If you are not having any other treatment, then in some circumstances your CBT therapist might recommend that you involve your GP. For example, a short-term course of prescription drugs might help you to benefit more from CBT.