Occurrence of neuropsychiatric symptoms and psychiatric disorders in mild Alzheimer's disease and mild cognitive impairment subtypes

Abstract

Neuropsychiatric disorders are common in cognitively impaired older persons, and associated with institutionalization and caregiver stress in Alzheimer's disease (AD). Few studies have compared the occurrence of both psychiatric disorders and neuropsychiatric symptoms in patients with AD and mild cognitive impairment (MCI) subtypes. We aimed to investigate the frequency of psychiatric disorders and neuropsychiatric symptoms in AD and MCI patients, compared to controls. We included 245 outpatients of a memory clinic in Rome, Italy (119 AD; 68 multidomain-MCI; 58 amnestic-MCI) and 107 controls. Categorical disorders of depression and apathy were diagnosed with structured interviews. Symptoms were evaluated with the Neuropsychiatric Inventory (NPI). The odds ratios (OR) of patients having neuropsychiatric symptoms compared to controls were calculated with logistic regression, adjusted for sociodemographic and clinical variables. A large proportion of AD (49.6%) and multidomain-MCI (44.1%) patients had depression disorder. Apathy disorder was common in AD (51.3%) but less frequent in amnestic-MCI (6.9%) and multidomain-MCI (14.7%). AD patients were three times more likely to have depression disorders (OR = 3.0, CI = 1.1-7.6) or apathy (OR = 16.9, CI = 4.6-61.8) compared to amnestic-MCI, and seven times more likely to have apathy disorder than multidomain-MCI (OR = 7.5, CI = 3.0-19.2). After apathy and depression, the most prevalent neuropsychiatric symptoms in AD and MCI were anxiety, agitation, irritability, night-time behaviors, and appetite disturbances. There was an increasing prevalence of many neuropsychiatric symptoms with increasing severity of cognitive syndromes. Clinicians should consider the relevance of neuropsychiatric disorders and symptoms in patients with cognitive disturbances, and incorporate a thorough psychiatric examination in the evaluation of patients.