Ricerc@Sapienza

Over the last five decades, a number of biological oriented
personality theories have been proposed to explain how anatomical
and functional differences in the human brain are responsible for
individual differences in personality. Catechol-O-methyltransferase
(COMT) gene for the Val158Met single nucleotide polymorphism

(rs4680) is known to influence the activity of the enzyme responsible
for dopamine metabolism and has been linked with various aspect of
personality dimensions and cognitive processes. In the present study,

non-clinical participants (201 women and 53 men) were adminis-
tered the Temperament and Character Inventory-Revised, Tellegen

Absorption Scale, Differential Attentional Processes Inventory, and
Waterloo-Stanford Group Scale of Hypnotic Suggestibility, Form C.
Among these participants, COMT polymorphism (parameterized as
a 3-level variable: 0 = Met/Met, 1 = Val/Met, 2 = Val/Val) was
assessed in 117 women and 51 men. Hypnotic Suggestibility scores
were significantly correlated with scores from the Absorption,

Extremely Focused Attention, and Dual Attention for Physical-
Cognitive task. We failed to find the expected significant association

between COMT and Hypnotic Suggestibility scores. In contrast, COMT
scores were significantly correlated with scores from Novelty Seeking
(r = -.15, p = .049) and its Disorderliness subscale (r = -.21, p =
.006). A principal component analysis (with varimax rotation),

performed on personality and attention measures, yielded a four-
factor solution: Factor-1 (Moderately Focused Attention, Dual Atten-
tion Cognitive-Cognitive, and Dual Attention Physical-Cognitive),

Factor-2 (Novelty Seeking, Reward Dependence, and Harm Avoidance),
Factor-3 (Hypnotic Suggestibility, Absorption, and Extremely Focused
Attention), and Factor-4 (Persistence). These factors accounted for
18.4%, 16.3%, 16.2%, and 12.3% of the total variance, respectively. These
findings guided us in the choice of the COMT, Persistence, Extremely

Focused Attention, and Absorption scores as predictors of Disorderli-
ness scores in separate multivariate regression analyses. Lower COMT

activity, higher Absorption scores, and lower Persistence scores
accounted for 18% of the total variance in the whole sample, and
10.8% in female sample. In male sample, higher Absorption and lower
Persistence scores significantly predicted Disorderliness scores,
accounting for 22% of the total variance. Since our male sample was
relatively small, further research is needed to understand gender
differences, if any, using a larger male sample.