[Cholinesterase inhibitors and depression in the elderly]

Background: Depression in the elderly is characterized by an atypical expression with delusion, major anxiety, behaviour disorders, somatic complains or cognitive impairment. These clinical aspects are suspected to be at the origin of the poor response to antidepressants observed in these cases. It is currently indicated to add sedative medicines to antidepressants, when a major anxiety is associated with depression, or an antipsychotic in the delusional forms of the depression. However, it is not consensually established that cholinesterase inhibitors can be helpful in depression with cognitive impairment. Cholinesterase inhibitors are efficient among patients with Alzheimer disease. They improve cognitive performances and slow down the degenerative process during the first years of treatment. Today, new findings on neurobiological mechanisms of depression involve a located degenerative process, with some similar anomalies in the brain in both depression and pre-Alzheimer states. New therapeutic trials have shown that cholinesterase inhibitors can be also efficient on depressed symptoms among patients with Alzheimer disease. These evidences support the hypothesis that the association of cholinesterase inhibitors to antidepressants can bring more benefits to depressed elderly patients.

Aim: Through a review of the literature and a case report, we tried to specify whether cholinesterase inhibitors can be useful in the treatment of depression among the elderly.

Case report: We report the case of a 68-year-old man who had presented, four years ago, a second episode of major depression with a cognitive impairment. Treated with an antidepressant (venlafaxine), the improvement was poor with major anxiety, slow thoughts, and an evidence of a persistent cognitive impairment. Despite normal cerebral scanning images, we decided to add a cholinesterase inhibitor (donepezil) to the same antidepressant. With this association, we rapidly obtained a total remission from depression with restitution of cognitive performances. This state is still maintained until today (four years after the last depressive episode) with no new mood relapses. Recent cerebral scanning images did not show any degenerative process.

Conclusion: The association of cholinesterase inhibitors and an antidepressant seems a good alternative, when the response to antidepressant is partial in depression with cognitive impairment in the elderly. However, further therapeutic trials are still needed, to prove the usefulness of cholinesterase inhibitors among depressed elderly patients.