Table 1.

Heritability estimates for different drugs of abuse^§

Phenotype	Heritability estimates
Smoking
Persistence	28 – 84%
Cigarette consumption	45 – 86%
Nicotine dependence	31 – 75%
Nicotine withdrawal symptoms	26 – 48%
Smoking cessation	50 – 58%
Alcoholism
Alcohol abuse/dependence	50 – 70%
Consumption levels	45 – 58%
Problem drinking	8 – 50%
Opiates/Heroin
Abuse and/or dependence	43 – 60%
Sedatives
Abuse and/or dependence	29 – 58%
Psychostimulants
Abuse and/or dependence	42 – 74%

^§These studies have been reviewed in greater detail elsewhere (3, 4, 6, 7, 57). A list of the primary references can be found in Supplementary Table 2.