The prevention and treatment of age related mental diseases, including cerebrovascular dementia and Alzheimer's disease, are complicated by diagnostic problems and by the lack of specificity of the so-called "cerebroactive" drugs. These agents are frequently prescribed at the patient's or the relatives' request, without clear-cut evidence for their therapeutic efficacy. The economic consequences of these usually long term treatments should also be taken into consideration. A few "cerebroactive" agents may marginally slow down or modulate the progression of the various neuropathological processes: for example "vasoactive" drugs (such as pentoxifylline) in cerebrovascular dementia and "nootropic" drugs (such as co-dergocrine) when advanced and irreversible mental impairment has not yet occurred. There is currently no effective treatment for Alzheimer's disease. The results obtained with neurotransmitter replacement therapy, e.g. with the acetylcholinesterase inhibitor tacrine, have generally been disappointing, even if a small clinical improvement has been observed in a few selected patients.