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.
Laakso
Aki
A
Department of Pharmacology and Clinical Pharmacology, University of Turku, Kiinamyllynkatu 4-8, 20520 Turku, Finland.
Wallius
Esa
E
Kajander
Jaana
J
Bergman
Jörgen
J
Eskola
Olli
O
Solin
Olof
O
Ilonen
Tuula
T
Salokangas
Raimo K R
RK
Syvälahti
Erkka
E
Hietala
Jarmo
J
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