Vocabulary Loss and Depression

Dear Ask The Doctor: I've had severe short-term and verbal memory loss, emotional instability, loss of pleasure, lack of motivation, and other characteristic symptoms of depression for nearly two years. I have improved significantly with time through an effort to re-learn vocabulary (I initially forgot even very simple words, such as helpful), avoid caffeine and sugar, keep busy, avoid comparisons to what I "used to" be able to do, and so forth; I have improved drastically, but mental exertion still causes a rapid and drastic exacerbation of my symptoms. Why does mental exertion worsen my depression and memory loss? What can I do to rebuild my mental stamina / avoid relapse caused by mental exertion?

Dear Jocelyne: Memory loss specific to language is not a symptom of depression and should be assessed by a physician.  At the very least, a CT and MRI of the brain should be performed and other tests depending on your past medical history and social behaviors.  In Mood disorders, it is common for the brain to block out memories of traumatic events but it is never normal to loose vocabulary.