CannabisScientists

Smoking anything is bad for your lungs. Vaping is better than smoking. Edibles are better than vaping (for your lungs). We don't really know enough about its effects on cancer/lung cancer. Cannabinoids seem to have some anti-cancer properties in controlled lab experiments but the real-world implications are unknown.

It is well established that THC can produce anxiety, with higher doses of THC causing high levels of anxiety. Many of the strains you can find now in the US and Canada are, as you say, far higher in THC than most cannabis you would typically find growing wild in India or Nepal or in Morocco - i.e. mountainous areas where cannabis grows as a 'weed'. They have been bred to be like this, and it is an interesting question what effect using such THC-rich products will have on long-term cannabis users.

Cannabis is cannabis, and the whole sativa indica thing is just about plant genetics. The reality is that most strains now have been so cross-bred over time that the sativa/indica distinction is essentially unhelpful and misleading.

There are lots of interesting papers in this space - try this one for starters: https://www.liebertpub.com/doi/full/10.1089/can.2016.0017

Different strains of cannabis may produce different effects because of their chemical composition. But the botanical classification of 'indica' and 'sativa' are not related to the chemical composition of cannabis plant. Indica and sativa describe how the cannabis plant looks, and they do not describe the cannabinoid profile of the plant. However, it's very common for people to experience indica and sativa differently because people expect to experience them differently. In the same way that some people say 'oh, drinking gin makes me sleepy but whisky wakes me up', when really it's all just alcohol. But the expectation ends up causing the effect.

At the molecular level in cellular models, there is currently no evidence that terpenes modulate the activity of phytocannabinoids (including THC) at any receptors--including the cannabinoid type 1 receptor (CB1) responsible for the psychoactive effects of THC. It is hypothetically possible that terpenes act on olfactory G protein-coupled receptors (GPCRs) to modulate some aspects of the cannabis experience, but this has not been demonstrated. Beer contains lots of terpenes (from hops), and these mainly alter aroma and flavour.

There are more than 30,000 different terpenes in nature. Those found in cannabis are no different than the same terpenes found in other sources (foods, beer, fragrances, etc.), and all of the major terpenes found in cannabis are also found abundantly elsewhere.

One way in which terpenes and other lesser-known cannabinoids might be modulating the cannabis experience is by altering that activity of metabolic enzymes that process THC. Again, this would not be expected to have a major effect on the perceived, subjective experience of cannabis intoxication.

Aside from THC (and a few analogues and homologues that occur in tiny quantities), there are no other compounds in cannabis that are known to cause intoxication. Perceived differences in intoxication from different strains of cannabis are very much likely due to power of suggestion and the human mind.

I would love to do a blinded, placebo-controlled study looking at the power of suggestion in perceived effects of cannabis use! I suspect marketing of strains play an enormous role, just as it does with the perceived experience of wine and whisky!

Hard to say why some people respond differently to cannabis when it comes to sleep. This is true for lots of drugs - some people just don't respond the way that most people do. Some sedating histamines, for example, will knock one person out but keep another person awake. THC does decrease the amount of time spent in the phase of sleep known as REM, which is when dreaming tends to occur. So that goes some way to explaining that. But to be honest - we don't know much about this. Another alternative explanation is that cannabis impairs memory formation - so it may be that you are still dreaming but that you just don't remember what you dreamt about in the morning very well.