There are suggestions that this is the case.
In our lab, we've looked at smoked cannabis, and we find that it goes into the blood very quickly. In five minutes after people smoke a cannabis cigarette, they achieve their peak blood THC levels. It declines relatively rapidly after that.
When we ask them if they feel the effects of the drug, we find there is a slight lag. It increases for a little bit beyond that five-minute window, and then it too begins to decline within a half an hour or so. There is this perhaps slight lag in terms of the impact on the self-reported sense of the effects of the drug, and it may be that there is, as well, for behavioural effects of the drug.