Personality traits associated with caffeine intake and smoking.
OBJECTIVE
Some studies find a relationship between certain personality traits, as impulsivity or sensation seeking, and caffeine consumption, but these studies do not consider the potential confounding effect of smoking on caffeine intake, a co-occurrence that has been well demonstrated in epidemiological and clinical studies. The main objective of this cross-sectional study was to analyze the association of personality with caffeine intake controlling for the effects of smoking; a secondary objective was to explore the effect of caffeine intake on the previously known relationship between personality and smoking.


METHODS
A sample of 498 adults answered a self-questionnaire including socio-demographic variables, and items regarding consumption of tobacco and caffeine. Personality was measured by the Temperament and Character Inventory (TCI-125). We analyzed the association of personality traits with both caffeine intake and smoking, controlling the possible confounding effects of sex, age and each substance with the other one.


RESULTS
Logistic regression analyses showed that the temperamental dimension of novelty seeking was associated with heavy caffeine consumption (>200 mg/day) (adjusted OR=2.0; 95% CI: 1.1-3.9), controlling for the effect of smoking. Moreover, novelty seeking was associated with both smoking (adjusted OR=1.8; 95% CI: 1.1-2.9) and heavy smoking (>20 cigarettes/day) (adjusted OR=1.8; 95% CI: 1.0-3.7), after controlling for the effect of caffeine intake.


CONCLUSIONS
Our study offers an epidemiological evidence of the relationship of novelty seeking, considered to be associated with low basal dopaminergic activity, with both nicotine consumption and heavy caffeine intake, two substances that enhance dopaminergic neurotransmission.
Gurpegui
Manuel
M
Department of Psychiatry and Institute of Neurosciences, Faculty of Medicine, University of Granada, Av Madrid 11, Granada, Spain. gurpegui@ugr.es
Jurado
Dolores
D
Luna
Juan D
JD
Fernández-Molina
Carmen
C
Moreno-Abril
Obdulia
O
Gálvez
Ramón
R
D000328:Adult; D002110:Caffeine / Q000494:pharmacology*; D000697:Central Nervous System Stimulants / Q000494:pharmacology*; D002605:Character; D003430:Cross-Sectional Studies; D005106:Exploratory Behavior / Q000502:physiology; D005260:Female; D006801:Humans; D007175:Impulsive Behavior / Q000523:psychology; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D009042:Motivation; D009538:Nicotine / Q000494:pharmacology; D018722:Nicotinic Agonists / Q000494:pharmacology; D010551:Personality / Q000502:physiology*; D010556:Personality Tests; D012907:Smoking / Q000523:psychology*; D012959:Socioeconomic Factors; D011795:Surveys and Questionnaires; D013694:Temperament / Q000502:physiology
D000697:Central Nervous System Stimulants; D018722:Nicotinic Agonists; D002110:Caffeine; D009538:Nicotine