Gifted Issues Discussion homepage Forums General Discussion What we fear most

Sorry for delay - life intervened.
Curiously I can't find that figure. There were 5353 people altogether in the analysis sample (i.e., once they'd excluded the people for whom they don't have all the data - and the paper did attempt to check whether the group for whom they do have all the data is representative), and they do give means and SDs for IQ score in a wide range of subgroups, all of which look kind of normal, so probably whatever you'd expect for that size sample - what would it be? Not huge.
Used in the last 12 months (at age 30).
The >130 group was between 1.1 and 1.8 times as likely to be using cannabis as the 115-130, depending on which group you look at (men, women, using IQ data from age 5, using it from age 10, with or without controlling for stuff). No very clear pattern within that except that all the ORs seem higher for the IQ-data-from-age-10 groups.
My impression is that occupational drugs tests are very rare in the UK, so I doubt that'd be a factor. They controlled for mother's and father's social class as assessed when the subjects were 5, and for subject's own: significant psychological distress (at 16), social class, monthly income, level of education (assessed at 30 years). Didn't seem to make much difference.

No, I think that's an outdated view for two reasons. First, it's now consensus, I think, that the optimal alcohol intake is not 0 (for most people - might be different if you have a strong family history of certain cancers, etc.) but I know of no reason to think there's consensus that any level of pot intake is beneficial. Second, I think the evidence that pot, even in rather moderate quantities, can precipitate schizophrenia in vulnerable individuals is now pretty strong, and quite worrying.

All my (high IQ) family have used illicit drugs - mother, father, uncles, aunts (cannabis for the most part, though my husband - who no longer uses any - has tried most things). None had addiction issues, some still, in their 60s use cannabis occasionally for recreational purposes. All those that did not have other issues (such as mental illness not related to drug use) have stable and successful careers and lives. I think there is a lot of fear around drug use that is not really supported by lived experience.

Don't get me wrong, I'm not promoting drug use and I don't mean that drug use is risk free - while I drink recreationally, I'm the black sheep in the family for not having tried much else because I'm not comfortable with the potential implications. My mother, who is mentally ill, regularly used cannabis when I was growing up with not terribly positive results. I also went to school with a guy, who I suspect was PG, who has ended up being regularly admitted to psych wards over the course of his adult life due to psychotic episodes apparently caused by his very heavy adolescent drug use - but there were other factors at play there too, including extreme family breakdown and abuse. So while I understand how detrimental it can be for vulnerable people, there is, I suspect, often more to negative outcomes than just the drug use. My understanding is that the majority of people who experiment with drugs have positive experiences, with no discernible negative outcomes.

There is a book on this that was recently published by an Australian journalist, Louise Pryor. I haven't read it, but is has been very positively received here by medical professionals and community groups for presenting a realistic look at recreational drug use:

http://www.amazon.com/Small-Book-About-Drugs-ebook/dp/B005DXOPFK

I certainly don't mean we should be forcing drugs down kids' throats, and there will be consequences for dd if I find she is using drugs before she's 18 (18 is when children come of age here), but I do thinking that panicking about them is unproductive and, largely, unnecessary. I think, much like many other risky things, kids need to be educated about the risks involved and how to handle themselves if they do get in to trouble (so many publicised young drug deaths here seem to have been as a result of kids not knowing what to do when things do go wrong, or not calling help because they don't want to get in to trouble).

What level of significance did they calculate that these results were at? Were there roughly equal numbers of subjects considered in each IQ sextile, or were they working from a sample that had a normal distribution of IQ?

It seems that with this sample size, if it was a normally distributed sample, you'd probably only have about 106 people at 98th percentile and above (over 130 IQ). That is few enough that each individual who reported in the affirmative would account for nearly a full percentage point increase in the rate of drug use for that group, and that could make a huge difference in the reported relative chances, since, IIRC, the rates of drug use they found at age 30 were in the single digits.

For the binary questions, they use the usual p<0.05 as the threshold value for reporting; many individual issues have much lower p values quoted. For the ORs mentioned in my previous post they give 95% confidence intervals (many of which are quite wide, yes, but not overlapping 1). Here's the main methodology paragraph in case it's more helpful:


The latter. (The former would be decidedly weird!)

On the last point, no: in the sample overall, at age 30 they found that 35.4% of men and 15.9% of women had used cannabis in the previous 12 months. They did indeed find lower percentages for other drugs, but cannabis is the only one for which they report results in IQ sextiles as opposed to tertiles, and that's what the ORs in my previous post refer to. Come to think of it, this may be precisely because their sample wasn't big enough to get significant sextile results for the less used drugs, as you suggest.