I don't agree. I believe that CBD is psychoactive in its own right. The commonly held wisdom is that CBD counteracts or ameliorates the effects of THC, is anti-psychotic, pain relieving but non-psychoactive.
So, I have my own theory. The only evidence I can offer is from experience. Firstly my own, both over time and one particular, recent incident. Secondly, an experience we can all share that provides insight - even without consuming cannabis!
Before the evidence though, I just don't think these four principal effects add up. Anti-THC, anti-psychotic, pain relief and non-psychoactive?
How can something be said to provide pain relief yet not provide any psychoactive effect? Why would nature evolve components that cancel each other out for no individual value?
In my experience, cannabis is nowhere near as simple as that. It is an anti-inflammatory and an analgesic in one. As well as CBD, THC provides pain relief in the sense of mood control. Many who use cannabis for chronic pain report that the pain is still there, it is just easier to cope with. We know that research is actively pursing the therapeutic effects of THCv, CBC, CBG and other cannabinoids. Even GW acknowledges that the less well known cannabinoids boost the effect of THC by up to 330%(see ref 1)! (So much for the deception that Sativex is just THC and CBD.)
The complex effect of more than 100 cannabinoids in every natural cannabis product is a very long way from being fully understood. A hopeful sign is that Echo Pharmaceuticals of Nijmegen is now offering cannabinoid extracts from Bedrocan cannabis as shown in the table.
Echo Pharmaceuticals. Available Cannabinoid Standards
It's not just cannabinoids though, cannabis also contains flavonoids and terpenes or terpenoids, all of which have an effect. This is why modern, reductionist medicine finds it so difficult to deal with cannabis, even though its safety and efficacy have been proved over more than 5000 years.
Of course, CBD does ameliorate or modify the effects of THC and here I turn to my long term, personal experience. In the 1970s, I was raised on Lebanese hash, Red Leb and Yellow or Gold Leb. It was gorgeous, moist and oily and although I had no idea at the time I can now look back and recognise that it was well balanced with CBD and THC and individual characteristics accounted for by other components. I don't know whether they were cannabinoids, terpenoids or something else but they define each individual type of weed or hash and give each one a particular quality. This is where the analogy with wine is so appropriate. Cannabis can be understood and appreciated in a very similar way.
We now know that the Moroccan hash that dominated the 1980s was balanced with THC and CBD. High THC charas (hand-rubbed hashish) contains far higher proportions of CBD than is found in modern, prohibition-fuelled, maxed out THC weed. It was a far more pleasant smoke. It was mellow. It's true that some modern weed is far too buzzy, nervy. Yes, it is far more likely to make you a little para than a bit of hash. I have experimented with a few sprays of Sativex on a couple of occasions and it is easy to recognise the effect as being more like CBD rich hashish.
So it was with delight that a few weeks ago, for the first time in too many years, I found myself with a small piece of fine Afghani charas. It was delicious, in a smoochy, comfortable, completely relaxing way that I miss so much. I'm a pure smoker and have been for 20 years so I burned it in my small brass pipe and eked it out as for as long as I could. I remembered what well balanced cannabis is. In fact, what it would be to have a choice? That's never been the case in Britain. All my life I've just been grateful for whatever Mr Big has on offer. Only very rarely and a long time ago do I remember being offered a choice. That was always the delight of a trip to the Dam and a few days with the equivalent of a box of chocolates or the cellars of some fine vintner.
My final evidence is the BBC documentary "Should I Smoke Dope". It's actually an excellent programme, spoiled by the chav rock chick presenter who makes the whole thing come across as very trivial. In fact, it provides some fascinating information. In particular, when our heroine is fed intravenous THC alone and then combined with CBD. The results are revelatory and anyone who has experience of varieties of cannabis will recognise the truth in what is shown. It makes my point for me perfectly.
CBD doesn't just cancel out THC. It modifies the effect of cannabis in a vital way. Those, much younger than me, who have been brought up on "prohibition skunk" are missing out big time and yes, are put at greater risk as a result. It is undoubtedly true that any negative effect of cannabis is likely to come from high THC content. Prohibition is a deeply harmful, self-defeating, dangeous and immoral policy.
It also prevents the delightful, positive, life-enhancing wondrous gift of cannabis from being at its best and that, in my opinion, is a sin.
The ingredients having the greatest effects on the cannabis taste would most probably be the fragrant terpenes within the essential oils. Some of these have their own pharmacology and have been cited as likely synergists in mixtures with cannabinoids (McPartland and Russo, 2001). The potential benefit of these ingredients was demonstrated in a test measuring pain relief in mice, in which unknown powerful synergists produced a 330% increase in activity compared to THC alone (Fairbairn and Pickens, 1981). Synergistically improved efficacy of cannabis extracts over THC-alone was also demonstrated in a mouse model which assessed their antispacticity effects (Williamson, 2001). David Potter 2009