Behavioral correlates of GABAergic disruption in Alzheimer's disease

Background: Losses of γ-aminobutyric acid (GABA) have been variably demonstrated in Alzheimer's disease (AD) and may be related to the presence of behavioral and psychological symptoms of dementia (BPSD) in AD. Our objective was to assess the relationship between plasma GABA (pGABA) levels and specific BPSD in patients with severe AD. Methods: pGABA levels and BPSD were measured in 14 institutionalized AD patients (8M/6F, mean age ± S.D. = 85.6 ± 4.5 years) with severe cognitive impairment (Mini-mental State Examination score = 4.5 ± 4.6) and prominent behavioral disturbances (Neuropsychiatric Inventory (NPI) score = 33.4 ± 23.6). Results: pGABA was positively correlated with depression and apathy scores on the NPI and negatively correlated with age. Apathy and age were independent predictors of pGABA levels. Conclusions: The final stages of AD are associated with GABAergic changes, which may contribute to depression and apathy in AD.