A biomedical research scientist blogger writes about marijuana potency:
…there’s a whole literature in which it is shown that if you manipulate the nicotine content of cigarettes, smokers will alter their smoking topography (volume per puff, puff duration, etc) in the direction of restoring the dose obtained from their usual brand. The marijuana literature is smaller…Nevertheless a close reading of the available literature in controlled human laboratory studies will suggest that marijuana smokers are also quite good at titrating dose in response to the content of the smoked product.
Another way to put this is that users smoke to reach a subjective high rather than to consume a certain number of puffs of a certain amount of drug. The product and route of administration are such that the overdosing variance would seem to be quite narrow relative to cases where the drug administration is more of a one-shot ballistic event (like swallowing a purported Ecstasy pill of unknown content, IV administration of drugs of uncertain purity / weight). Consequently I tend to doubt that the concentration of the source material plays a huge role in establishing marijuana dependence.
The Dish 