Personality traits and striatal dopamine synthesis capacity in healthy subjects.
OBJECTIVE
Neuroimaging and genetic studies suggest that individual differences in the brain dopaminergic system contribute to the normal variability of human personality (e.g., social detachment and novelty seeking). The authors studied whether presynaptic dopamine function is also associated with personality traits.


METHODS
Presynaptic dopamine synthesis capacity in the brain was measured with positron emission tomography and [(18)F]fluorodopa in 33 healthy adults, and personality traits were assessed with the Karolinska Scales of Personality. Associations were studied by using a linear regression model controlling for the effects of age and gender on both variables.


RESULTS
High scores on two of the anxiety-related personality scales, somatic anxiety and muscular tension, and on one aggressivity-related scale, irritability, were significantly associated with low [(18)F]fluorodopa uptake in the caudate. No statistically significant associations were observed between [(18)F]fluorodopa uptake and the detachment scale or scales related to novelty-seeking behavior (impulsiveness and monotony avoidance).


CONCLUSIONS
The results suggest a role for the dopaminergic system in the regulation of anxiety in healthy subjects. Together with previous studies, they also indicate differential involvement of various components of the dopaminergic system in normal and pathological personality traits.
Department of Pharmacology and Clinical Pharmacology, University of Turku, Kiinamyllynkatu 4-8, 20520 Turku, Finland.
Aki
A
Laakso
Esa
E
Wallius
Jaana
J
Kajander
Jörgen
J
Bergman
Olli
O
Eskola
Olof
O
Solin
Tuula
T
Ilonen
Raimo K R
RK
Salokangas
Erkka
E
Syvälahti
Jarmo
J
Hietala
D000328:Adult; D000367:Age Factors; D002421:Caudate Nucleus / Q000000981:diagnostic imaging / Q000378:metabolism / Q000502:physiology; D003342:Corpus Striatum / Q000000981:diagnostic imaging / Q000378:metabolism / Q000502:physiology*; D004298:Dopamine / Q000096:biosynthesis / Q000502:physiology*; D005260:Female; D019788:Fluorodeoxyglucose F18; D007839:Functional Laterality / Q000502:physiology; D006801:Humans; D007508:Irritable Mood / Q000502:physiology; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D010551:Personality / Q000145:classification / Q000502:physiology*; D010552:Personality Assessment / Q000706:statistics & numerical data*; D010554:Personality Disorders / Q000175:diagnosis / Q000000981:diagnostic imaging / Q000503:physiopathology; D011699:Putamen / Q000000981:diagnostic imaging / Q000502:physiology / Q000503:physiopathology; D012737:Sex Factors; D012928:Social Desirability; D014055:Tomography, Emission-Computed
D019788:Fluorodeoxyglucose F18; D004298:Dopamine