New research from The Netherlands shows that people who smoke high-potency cannabis end up getting higher doses of the active ingredient (THC). Although they reduce the amount they puff and inhale to compensate for the higher strength, they still take in more THC than smokers of lower potency cannabis.
For the past decade or more, the common sense idea that high strength cannabis leads to higher doses of THC and therefore poses a greater risk of unwanted effects such as dependency has been challenged and labelled the 'potent pot myth'. It has been argued that smokers of strong cannabis adjust their drug intake to compensate for the potency, usually by inhaling less smoke or rolling weaker joints. It is even argued that 'super pot' is healthier for cannabis users because they get their desired high while inhaling less lung-harming smoke.
The Dutch researchers in this study observed 98 experienced cannabis smokers as they rolled and smoked joints using their own cannabis samples, which were of varying concentrations. Those who made strong joints inhaled smaller volumes of smoke, presumably in an attempt to titrate the amount of THC taken into the body. But these titration efforts were only partially successful, compensating for roughly half of the THC strength.
So although smokers of strong cannabis alter their smoking behaviour to compensate for the higher potency, they don't alter it enough. There is some truth to the 'potent pot myth'.
More information: van der Pol P, Liebregts N, Brunt T, van Amsterdam J, de Graaf R, Korf DJ, van den Brink W, and van Laar M. Cross-sectional and prospective relation of cannabis potency, dosing and smoking behaviour with cannabis dependence: An ecological study. Addiction, 109: DOI: 10.1111/add.12508