"My friend uses cannabis for anxiety, but I use it for muscle pain. I find that some of the strains that I use will give her some uneasy feelings, while I normally don’t experience the negative aspects she gets from these strains. Where is a good place to find if certain strains can cause anxiety?"
It can be difficult to gauge what percentage of THC in a flower strain will activate the fight flight sympathetic nervous system to trigger symptoms of hyperarousal that can include paranoia, "unease"’, nausea, headache and even mania. I have evaluated responsible professional people who report using high THC strains that triggered symptoms of florid mania. Fortunately the duration of action of inhaled cannabis is only four hours and the peak effect is only 30 minutes. The rapid onset within five minutes creates a "bolus" drug effect that many people find pleasurable. It can lift the mood, enhance creativity and promote a positive mental attitude. In my professional opinion I believe the sympathetic hyperarousal symptoms that are most unpleasant are seen in strains greater than 20% THC. When I authorized my first patients in 2007 I was taught that it was not possible to find THC strains with greater than 20% THC! Times have changed.
My professional belief is that delicious, nutrition grade, low dose edibles in doses as low as 5 to 10 mg THC offer the most pleasant and long acting effect on mood, pain and muscle tension. In very low doses THC relieves anxiety but does not trigger the adverse effects seen in high dose THC edibles and flower strains. Low dose edibles are far and away the most cost effective way to use cannabis for chronic anxiety or pain.