Psychogeriatrics (PG) is a multidisciplinary specialty in clinical neuroscience dealing with brain disorders in the elderly population. As any other biomedical field PG has to establish an educational and practical framework in epidemiology, etiopathogenesis, diagnosis, treatment, and social, ethical, and legal issues associated with brain aging and age-related central nervous system disorders. Understanding the molecular basis of aging will help to characterize and differentiate the fundamentals of pathological aging and psychogeriatric ailments. Modern epidemiology of age-related brain disorders have to incorporate novel diagnostic criteria, biological markers, and genetic epidemiology to its methodological armamentarium to avoid bias. Molecular genetics will help to conceptually redefine many psychogeriatric disorders depending upon its genetic component and those interacting environmental factors leading to the phenotypic expression of given diseases. Genetic testing for monogenic and complex/polygenic/multifactorials disorders has to be included in diagnostic protocols since approximately 60 to 80% of major psychogeriatric disorders are genetically driven. It is also important to distinguish mutational genetics from susceptibility genetics in order to establish novel therapeutic strategies and preventive programmes. Genomics, proteomics, and pharmacogenomics are novel fields from which PG can benefit in the areas of etiopathogenesis, diagnosis, and treatment. Drug development in PG requires updated regulations in developed countries. New pharmacological treatments for aging brain disorders are needed. Pharmacogenomics will become an optimal strategy for drug development, contributing to design a molecular psychopharmacology for the elderly, individualizing drug therapy, optimizing efficacy and safety, and reducing unnecessary costs. ing. In this regard, geriatric neuroscience would integrate the following disciplines: geriatric psychiatry, psychogeriatrics, neuropsychiatry, geriatric neurology, behavioural neurology, neurogeriatrics, neuropsychology, geriatric psychology, neuropsychopharmacology, neuroimaging, basic neuroscience, and neurogeneti~s.',~,~) At the clinical setting, in CNS disorders of the elderly, there are no definitional boundaries between neurology and psychiatry from a practical perspective; the so far established differences are the result of habits and traditional training rather than practical distinctions. Diagnostic procedures and therapeutic alternatives are also common and complementary in CNS disorders of the elderly when applying a neurological or psychiatric approach. The elucidation, prevention, and treatment of most CNS disorders will depend largely on advances in neuro~cience.~)Although the early beginnings of neuroscience are linked to Santiago Ramon y Cajal and Charles Sherrington at the turn of the past century, followed by the pioneering work of
