DNA was isolated from either whole blood (93% of participants) or buccal swab (7%) samples. The FAAH C385A polymorphism (rs324420) was genotyped via Taqman allelic discrimination. Polymerase chain reactions contained 50 ng of genomic DNA, 1× quantitative polymerase chain reaction Rox Universal Genotyping master mix (Applied Biosystems, Carlsbad, CA, USA) and 1 × primer/probe mix (Applied Biosystems; Assay ID C189730610) made up to a total of 7 μl with distilled water. Thermocycling was performed using an Applied Biosystems 9700 PCR machine with the following parameters: 15 min at 95 °C, followed by 35 cycles of 95 °C for 15 s and 60 °C for 45 s. Genotypes were discerned via end-point fluorescence using an Applied Biosystems 7900HT machine set up in allelic discrimination mode and the SDS 2.1.1 software (Applied Biosystems).
