Coincidentally, I just took a class at school on neurobiology, and neuroplasticity was our buzzword. I wrote a paper for class on "the neurobiology of psychotherapy" so I've been reading some of those papers mentioned by TheByzantine. I think it's totally cool that science is now figuring out why and how psychotherapy helps people. It also will allow more and more the therapist to choose the right directions in therapy based on the person's brain deficits.

I guess there are ways they could interfere, but also ways they can help, just like therapy. In my reading, I found numerous studies about brain circuit remodeling that are promoted by medication. For example, SSRIs promote growth of new hippocampal neurons. It's a fascinating field. I'm not trying to minimize the negative experiences some have had with medication, as seen in the stories told by several on this thread. Unfortunately, the knowledge to help everyone automatically with the right med or the right therapy is just not there yet (which pill? which therapy exercises?). A big challenge now is the diagnostics--how does one know what treatment a person's brain needs? It can be a lot more challenging to figure that out than just looking for a rather primitive symptom cluster in a person (low mood + insomnia + hopelessness, etc.). Right now it's hit or miss, not to mention the genetic component. For some individuals, medications may allow them to respond to psychotherapy, so a combination can help where neither alone gives much traction.

I don't think a lot of therapists know about the brain work. I checked in the therapist training program at my school and they don't have any classes on neurobiology or the brain. Maybe they learn brain-based therapies in their classes on individual, group, and family therapy but it is not apparent to me that content is included from looking at course titles and descriptions.

Here are two general audience books about neuroplasticity for those who want to learn more. The Siegel book focuses on psychotherapy, the Doidge book has some on talk therapy but also contains information on other therapies for brain healing.
The Brain That Changes Itself by Norman Doidge
Mindsight by Daniel Siegel