Most doctors are now seeing that the body and mind are inter-related. A lot of physical illnesses are known to cause depression ~ just as a lot of emotional illnesses impact our physical health.

While my example doesn't specifically apply to your Q, you can see my experience:
I had a complex partial seizure at age 20. Went to the ER, but vague tests showed nothing. He wanted me to come back for more expensive tests at a later date, which I couldn't afford. My insurance was horrible!
I began having panic attacks.
Depression kicked in.
Lots of complex partial seizures inter-mixed with panic attacks.
Deeper depression ~ became a prisoner in my house, fearful of being alone. After a few years...
A tonic-clonic seizure sent me to ER, and involved a few expensive tests, finally revealing my illness: temporal lobe epilepsy.

My anxiety and depressive symptoms quickly disappeared as treatment for my seizure disorder began. I have learned since, however, that I am very vulnerable to major depression. It doesn't take much to send me spiraling downward. I believe that both medical and emotional illnesses become rather complex when one is actively dealing with both.