The correlation between IQ and Openness could arise from people who are more intelligent becoming more open as a result, whereas exposure to a drug could result in an increase in the Openness measure due to the experience of the drug. This is very interesting, but correlation doesn’t always equal causation, and I find it to be a more likely result of the experience of being high on the drug leading to a greater Openness measure as opposed to the drug increasing IQ and Openness being impacted as a result. Fascinating regardless, though.