(e.g. alcohol and cannabis), but for many other SUDs insufficient data exist (e.g. for opioids and cocaine) for this pattern to be potentially confirmed as universal. An exception to the difference between frequency/quantity versus dependence is nicotine, where a high genetic correlation is observed (rg=0.95)27; this may be explicable on the basis that nicotine is so addictive and available that regular smoking very readily engenders physiological dependence84.
