Acute tryptophan depletion and Lewy body dementias.

Background: Studies using acute tryptophan depletion (ATD) to examine the effects of a rapid reduction in serotonin function have shown a reduction in global cognitive status during ATD in Alzheimer's disease (AD) and Parkinson's disease (PD). Based on the severe cholinergic loss evident in dementia with Lewy bodies (DLB) and Parkinson's disease and dementia (PDD), we predicted that a reduction of global cognitive status during ATD would be greater in these conditions than in AD.

Methods: Patients having DLB or PDD underwent ATD in a double-blind, placebo-controlled, randomized, counterbalanced, crossover design.

Apathy in older patients with type 2 diabetes.

Objective: To determine the prevalence, incidence, persistence, likely causes, and consequences of apathy in patients with Type 2 diabetes and to compare the prevalence with a healthy control sample.

Design: Cross-sectional comparison of diabetic and nondiabetic samples; longitudinal follow-up of diabetic sample.

Setting: Academic research department.

The effects of acute tryptophan depletion on neuropsychological function, mood and movement in the healthy elderly.

Few studies have investigated the function of the serotonin (5-HT) system in the elderly. Previous studies have shown effects of reducing serotonin function, by acute tryptophan depletion (ATD), on neuropsychological function in healthy subjects but this technique has not previously been employed over a wide age range in the elderly. This study compared the effects of ATD on mood, cognitive function and motor function in two groups of healthy volunteers, one group aged 50-69 and the other aged 70-89.