There are 3 main active ingredients in marijuana: THC, CBD, and CBN. The places I go get their strains and edibles/topicals/whatever lab tested so you know the %s of each. In general, higher CBD+CBN levels are better for pain relief and insomnia and will cause more grogginess/drowsiness than strains higher in THC which are more for appetite stimulation, euphoria, anxiety relief, etc.

At least in SF the legitimate dispensaries do a good job of informing you about these things and finding the strains that will accomplish what you want.

If I am trying to get relief for pain and insomnia, why would I begin with the assumption that I am looking for a strain of THC at all? Why not get medical advice on how to treat the pain/insomnia/underlying conditions?

People usually go to the weed doctor after they've exhausted other avenues. For one thing, if you have insurance it's going to be a lot cheaper to take standard pharma products than weed.

Because weed is safe enough to treat as an over-the-counter remedy? Because many people in this country find medical care to be inaccessible?

Because that advice is likely parroting what a pharma sales rep told the doctor over a sales dinner?

It is strange to pretend that the only valid drug to use for pain or insomnia is THC. What does that have to do with pharma sales reps?

You are incorrect about the effects of CBD, in fact modern research has shown it's effect to be more stimulating and has been compared to ritalin by those with experience.

For more modern up to date science backed information on CBD see projectcbd.org

CBN is not a primary cannabinoid, it's a breakdown product of THC and simply indicates how old or stale the cannabis is. It's primary effect is grogginess and general unpleasantness so you want to avoid it as much as possible.

Any dispensary that says CBD is good for insomnia is simply repeating long disproven but widely spread information.

Look at THC / CBD proportions. There's research [0] into CBD mitigating THC's interference with memory formation.

Also, intentionally-high-CBD strains are under development [1]:

"A high-CBD cannabis strain was developed in the 1980s by David Watson and Robert Clarke, American naturalists who founded a company called Hortapharm in Amsterdam to pursue their goal of developing plant strains for different purposes. (The day Watson and Clarke became expatriates is the day the U.S. lost its lead in the field of cannabis therapeutics.) In 1998 Hortapharm sold its seed stock to a British start-up, GW Pharmaceuticals, which has since developed a strain that expresses 97% of its cannabinoid content as CBD.

GW plans to test its high-CBD strain as a treatment for rheumatoid arthritis, inflammatory bowel diseases, psychotic disorders, and epilepsy. It is now in Phase 2 trials to determine the dose levels to use in clinical trials involving people. GW mixes its high-CBD and high-THC strains in a 1:1 ratio to make Sativex, a plant extract formulated for spraying under the tongue that has been approved in Canada and elsewhere to treat neuropathic pain associated with multiple sclerosis. CBD evidently bolsters the pain-killing effects of THC while moderating its psychoactivity."

[0] http://www.nature.com/news/2010/101001/full/news.2010.508.ht...

[1] http://www.counterpunch.org/2007/07/14/who-s-afraid-of-canna...

From my limited understanding THC is the aspect that causes the 'high' whereas the CBD's are effective at pain relief, seizure control, and generally the medical benefit side of things. Around Denver there are a whole class of food additives and edibles that are high in CBD's because of this effect.