Background: Personality changes are common in early stages of many neurodegenerative
disorders and often precede cognitive deficits. In individuals with cognitive impairment an
increase in feelings of distress and worry (neuroticism) and a decrease in social interpersonal
behavior (extraversion) are frequently observed. However, few studies have examined the
usefulness of personality assessment in combination with other clinical measurements for the
identification of individuals at risk of cognitive decline and dementia. The main aim of the
thesis was to examine the significance of personality characteristics in diagnosing prodromal
stages of dementia.
Methods: The thesis is based on a sample of patients examined for early dementia symptoms
at the Memory Clinic, Karolinska University Hospital. The study groups consisted of 35
patients diagnosed with mild cognitive impairment (MCI), 24 with subjective cognitive
impairment (SCI) and 26 controls recruited from the community. Study I examined patterns of
personality across study groups. Study II investigated degree of agreement between self- and
informant ratings of personality, in relation to cognitive function, in patient groups and
controls. Study III explored the usefulness of combining personality and cognitive
measurements in discriminating patients groups and controls. Study IV investigated differences
in cognition, personality and CSF biomarkers between memory clinic patients with varying
degrees of cognitive impairment. We also analyzed which variables predict conversion to
dementia at follow up after three years.
Results: Study I: Patients with MCI and SCI presented specific patterns of personality with
higher scores in traits related to anxiety proneness and aggression-hostility and lower in traits
of extraversion, compared to controls. Study II: Correlations between patient- and informant
ratings of patients’ personality were fair to moderate on a majority of personality traits.
Measures of incongruence between patients and informants were significantly larger in MCI
than in controls across personality scales. Incongruence between raters was negatively
correlated with a measure of global cognitive function. Study III: Combining cognitive and
personality measurements resulted in a better discrimination between groups than any of the
measurements used alone. Cognitive tests discriminated MCI from SCI and controls, while
personality features separated SCI from controls. Study IV: Three years before diagnose,
converters to dementia showed a profile of cognitive impairment, higher levels of neuroticism,
and lower levels of extraversion and Aβ42, respectively. Low levels of Aβ42 and low results
in an episodic memory test, but not personality, predicted conversion to dementia.
Conclusions: Patients with MCI and SCI differ in their patterns of personality compared to
controls, but not when compared to each other. Disagreement between patients with MCI and
their informants may be related to cognitive impairment, indicating an early loss of selfawareness. Combining personality assessment with cognitive measurements improves
discrimination of patients at risk of cognitive decline. Personality has an independent role early
in the disease process, but does not predict disease progression
