[zhengyi13]

Not necessarily, particularly depending on what you specifically want to treat.

If you go poking around weedmaps.com (well, after their site starts functioning again :/), and look into strain-specific details there, there absolutely are low THC strains available, and also amazingly high THC level strains. High and low CBN/CBD, etc.

In addition, they have some space dedicated to breaking out the main/known active contituents in MJ, and what they're believed best to affect.