Diagnostic criteria for apathy in clinical practice

Background: Apathy is an important and distressing behavioural symptom in Alzheimer's disease and in various neuropsychiatric disorders. Recently, diagnostic criteria for apathy have been proposed. Objectives: In groups of patients suffering from different neuropsychiatric diseases, (i) to estimate the prevalence of patients meeting the proposed diagnostic criteria; (ii) to estimate the concurrent validity of the criteria with the neuropsychiatric inventory (NPI) apathy item; (iii) to identify the most frequently met criteria or sub-criteria in each specific neuropsychiatric disease and (iv) to estimate the inter-observer reliability of the diagnostic criteria for apathy. Methods: This cross-sectional, multicentric, observational study was performed on 306 patients. Each of the participating centres had to check the presence of apathy according to the diagnostic criteria for apathy in consecutive patients belonging to the following diagnoses list: Alzheimer disease (AD), mixed dementia, mild cognitive impairment (MCI), Parkinson's disease (PD), Schizophrenia (DSM-IV) and major depressive episode. In addition to the clinical interview, the assessment included the Mini Mental Score Examination (MMSE) and the NPI. At the end of the visit, clinicians were required to check the diagnostic criteria for apathy. Results: Using the diagnostic criteria for apathy, the frequency of apathy was of 53% in the whole population, 55% in AD, 70% in mixed dementia, 43% in MCI, 27% in PD, 53% in schizophrenia and 94% in major depressive episode. In AD, mixed dementia, MCI and PD, the NPI apathy score was significantly higher for patient fulfilling the apathy criteria. Goal-directed cognitive activity (criteria B2-Cognition) was the most frequently observed domain followed by goal-directed behaviour (criteria B1-Behaviour) and emotion (criteria B3), respectively. Inter-rater reliability was high for the overall diagnostic (kappa coefficient = 0.93; p = 0.0001) and for each criteria. Conclusion: This study is the first one to test the diagnostic criteria for apathy in clinical practice. Results make the diagnostic criteria useful for clinical practice and research