Alcohol in the human body gets there pretty much one of two ways: either it is taken in food and drink, or it is manufactured as a breakdown product of sugars. Of course, a blood alcohol level high enough to cause inebriation came about from an outside source, but the blood, and more interestingly, the CSF levels of ethyl alcohol are not zero, even in a person who has never taken a drink or other subtance containing ethanol.

(Paton A. Alcohol in the body. BMJ. 330(7482):85-7, 2005 Jan 8. UI: 15637372)

Abbreviations ADH: alcohol dehydrogenase; AER: alcohol elimination rate; ALDH: aldehyde dehydrogenase; ASPD: antisocial personality disorder; CHRM2: acetylcholine receptor M2; COGA: Collaborative Study of the Genetics of Alcoholism; GABA: [gamma]-aminobutyric acid; GABAA: [gamma]-aminobutyric acid A; 5-HTT: serotonin (5-hyrokytryptamine) transporter; 5-HTTLPR: 5-HTT gene-linked polymorphic region; Mpdz: multiple PSD95/DLG/ZO-1 domain protein gene; NACP: [alpha]-synuclein gene; NIAAA: National Institute on Alcohol Abuse and Alcoholism; npr-1: neuropeptide receptor like protein gene (Caenorhabditis elegans); NPY: neuropeptide Y; OPRM1: µ-opioid receptor gene; Per2: period-2 gene; QTL: quantitative trait locus; SNP: single-nucleotide polymorphism.

Higuchi S. Matsushita S. Kashima H. New findings on the genetic influences on alcohol use and dependence. [Review] [165 refs] [Journal Article. Review] Current Opinion in Psychiatry. 19(3):253-65, 2006 May.
UI: 16612210