Objective: To evaluate the extent to which the previously reported relationship between premorbid personality and psychopathological symptoms after the onset of Alzheimer disease (AD) is due to the use of a single informant for both personality and symptom information.
Design: Premorbid personality descriptions of patients with AD were obtained from 2 sources, primary caregivers and secondary informants, using the Personality Assessment Schedule and NEO-PI-R Neuroticism Scale, respectively. All information regarding depression and anxiety since the onset of AD was obtained from primary caregivers using clinical interviews and the Cornell Scale for Depression in Dementia.
Results: When data were obtained from the same informant, significant relationships were found between premorbid personality and both presence of depression and the severity of anxiety symptoms. When data were obtained from 2 different informants, the only significant relationship was between premorbid neuroticism and anxiety severity.
Conclusion: As in a previous report, there was a relationship between premorbid personality and depressive symptoms in AD, but only when personality and symptom information was obtained from the same informant. On the other hand, there was a relationship between premorbid personality and severity of anxiety symptoms both when personality and symptom information came from different informants as well as from the same informant. These data suggest that retrospective bias contributes to the apparent consistency between premorbid personality and some aspects of psychiatric symptoms in AD, specifically depression.