Earlier quoted context omitted.
Could it be, at the onset? The decision to take drugs? Where one is suffering from depression or some form of chemical imbalance? Or, could one be prone to risk taking behavior? Is the precursor to risk taking behavior, biochemical?
I don't know if it's a true "decision" to take drugs for many people. If they have crippling pain due to an injury, they may be prescribed pain medication and then find they can't get off. See my other comment for a scenario.
Prescription rates are very high to support your example [0]
Recreational use is a bit harder, for me at least, to gauge. I found the 2017 global drug survey [1] showing about 2% opium/heroine use among respondents.
[0] https://www.cdc.gov/drugoverdose/maps/rxrate-maps.html
[1] https://www.globaldrugsurvey.com/wp-content/themes/globaldru... (I wasn’t very familiar with this source, but I saw 10+ citations including some respectable journals like BMJ, https://www.globaldrugsurvey.com/about-us/methods-and-limita...