A 74 year woman suffering from depression since her early thirties even though she has taken anti depressants since then. why has she never recovered?

Depression: If you have not been in a constructive psychotherapy with a mental health professional you trust and believe in you may have not had the opportunity you deserve to combat deperssion. Medication without significant psychotherapy, individaul and group are essential to resolve depression. My book, "changing your inner voice" tells the stories of several people who have become depression free.

Treatment resistance: It is possible that there is another anxiety disorder, add, or another issue that has been missed. Has ECT ever been tried? Is there a marital difficulty or unresolved past traumas/ptsd? The scenarios are numerous to account for this. It is sad if it is because of inadequte attempts at augmentation. Then, of course there are rare people who remain depressed because they have an untreatable illness.