In order to collect a buccal sample, volunteers were given a 1.5 fl. oz. bottle of Scope mouthwash (15 wt% of alcohol) and asked to swish the mouthwash vigorously throughout the mouth for one minute and then expel it into a provided plastic collection cup, where it was immediately frozen. DNA was extracted, purified by organic extraction and ethanol precipitation, and then dissolved to a final concentration of 10 ng/ul for amplification by Polymerase Chain Reaction (PCR) (Vandenbergh, Anthony & Whitfield, 2003). Amplification followed the published procedure of Serretti et al, 1999 (, 1999). Oligonucleotide primers flanking the 5-HTT-linked polymorphic region (5-HTTLPR) and corresponding to the nucleotide positions ranging from −1,416 to −1,397 (5'-GCGTTGCCGCTCTGAATTGC-3’) and from −910 to −889 (5'-GAGGGACTGAGCTGGACAACCCAC-3’) of the 5-HTT gene regulatory region were used to generate the long, 528-bp, fragment and the short, 484-bp, fragment. PCR amplification was carried out in a final volume of 30 μl consisting of 50 ng genomic DNA, 2.5 mM dNTPs, 0.1 μg of sense and antisense primers, 10 mM Tris-HCl (pH 8.3), 50 mM KCl, 1.5 mM MgCl2, 5% dimethyl
