Objective: To evaluate the emotional disturbances in patients with Alzheimer's disease (AD) using both a categorical and a dimensional approach.
Design: Prospective study.
Setting: Outpatient clinic in a neurological department from a general University Teaching Hospital.
Measures: A semi-structured interview was used to fill in the Hamilton Depression Rating Scale, the Retardation Rating Scale for depression, the Tyrer and Covi scales for anxiety, and the Depressive Mood Scale for emotional disturbances. The cognitive status was assessed by the Mini-Mental State Examination and the Mattis Dementia Rating Scale.
Patients: One hundred eighteen consecutive AD outpatients fitting the criteria for probable or possible AD, according to the National Institute of Neurological and Communication Disorders and Stroke and the Alzheimer's Disease and Related Disorders Association, were compared with 34 community-dwelling healthy older controls and with 20 inpatients meeting the diagnostic criteria for depression according to the Diagnostic and Statistical Manual of Mental Disorders, 3rd Edition-Revised.
Results: No AD patient met the criteria for Major Depressive Episode or Generalized Anxiety Disorder, but 10 (8%) met the criteria for Dysthymic Disorder. AD patients scored significantly higher than the control group but lower than the depressed group for depressive and anxious symptomatology. Depressive symptomatology was correlated negatively to the cognitive status and positively to anxious symptomatology. Two main dimensions in emotional disturbances were described using the Depressive Mood Scale: Emotional Deficit (anhedonia, hypoexpressiveness) and Loss of Control (felt irritability, hyperexpressiveness). Emotional Deficit was correlated positively to the depressive symptomatology and correlated negatively to the cognitive status and the Loss of Control dimension. Loss of Control was correlated positively to the severity of the depressive and anxious symptomatology and weakly to cognitive performance.
Conclusion: Affective changes were found frequently in AD patients, but no major affective disorder was found. The dimensional approach seems to be more appropriate than the categorical approach to describe the emotional disturbances in these patients.