Psychiatric issues in non-Alzheimer dementias

Abstract

A wide range of psychiatric symptoms occurs in the non-Alzheimer dementias. These symptoms frequently cause distress for the patients themselves and their caregivers, and are thus important targets for therapeutic interventions. Quantitative psychiatric assessments are emerging for most dementing conditions with potential relevance in guiding practitioners in differential diagnosis. Neuroanatomical systems with shared metabolic characteristics, and common vulnerabilities to abnormal protein aggregation, may provide the basis for characteristic phenotypes of the neurodegenerative dementias that reflect the underlying prototype. Key systems include the parallel frontal–subcortical loops, linking frontal lobe regions to subcortical structures and back to frontal lobe areas, with important limbic and brain stem connections. Dementia with Lewy bodies and Parkinson's disease are synucleinopathies and typically exhibit visual hallucinations and rapid eye movement sleep disorders. Abnormalities of tau-metabolism are implicated in the frontotemporal dementias and progressive supranuclear palsy, and these patients frequently exhibit apathy and disinhibition. Psychiatric symptoms are also common in vascular dementia, depending on the location of the brain injury. Few controlled trials have focused upon the treatment of psychiatric symptoms in non-AD dementias. However, there is evidence that cholinesterase inhibitors, atypical antipsychotics and antidepressants can improve some of the psychiatric manifestations of patients with non-AD dementias.