3 ms·

Yeah, I particularly like two counter examples. Example 1: We have prevalence of schizophrenia of 1-2% both in countries with extremely high use (Australia, 25

Yeah, I particularly like two counter examples. Example 1: We have prevalence of schizophrenia of 1-2% both in countries with extremely high use (Australia, 25-30% last year) and extremely low (Japan, <1% last year). Still many schizophrenia cases have been associated with cannabis, but here's the twist: CBD displays antipsychotic properties, whereas THC exacerbates psychosis. That matches both the selfmedication hypothesis, and the trigger hypothesis, but the aggregate data still dispels the causal hypothesis. Example 2: The countries with the absolute biggest rates of tobacco prevalence are hovering around 40-50%, the US is sitting at around 20%. Among schizophrenics, though, it goes around 75-90%. But funnily enough, you don't see anyone claiming tobacco causes schizophrenia!

AstralStorm 8y ago
The tobacco lobby was quite successful debunking that myth. Cannabis had no lobby yet. The association is likely tied to self medication. Tobacco contains a low level monoamine inhibitor, these have some uses in psychiatry. (it is the main bit that is addictive - not really nicotine alone - harman and norharman, related to harmaline)
DanBC 8y ago
> But funnily enough, you don't see anyone claiming tobacco causes schizophrenia! We have extensive research on tobacco, so we know it doesn't cause psychosis. We now know that if you smoke cannabis at 15 you're more likely to develop schizophrenia than people who don't smoke; we know that this is dose dependent; and that the people who smoke will develop illness earlier than people who don't smoke. There are strong reasons to believe that cannabis will cause psychotic illness in some people. Obviously that's not all people. Just as not everyone who drinks heavily will become alcoholic, not everyone who smokes heavily will develop psychosis. But schizophrenia is sufficiently harmful that we want to provide good warnings to people to take care with cannabis. Avoid use if you're under 21; avoid heavy and prolonged use; seek help early if you're having trouble. When campaigners claim cannabis is a harmless herb they make it much harder for people like me who are trying to get it legalised and regulated.

AstralStorm 8y ago

The tobacco lobby was quite successful debunking that myth. Cannabis had no lobby yet. The association is likely tied to self medication. Tobacco contains a low level monoamine inhibitor, these have some uses in psychiatry. (it is the main bit that is addictive - not really nicotine alone - harman and norharman, related to harmaline)

DanBC 8y ago

> But funnily enough, you don't see anyone claiming tobacco causes schizophrenia! We have extensive research on tobacco, so we know it doesn't cause psychosis. We now know that if you smoke cannabis at 15 you're more likely to develop schizophrenia than people who don't smoke; we know that this is dose dependent; and that the people who smoke will develop illness earlier than people who don't smoke. There are strong reasons to believe that cannabis will cause psychotic illness in some people. Obviously that's not all people. Just as not everyone who drinks heavily will become alcoholic, not everyone who smokes heavily will develop psychosis. But schizophrenia is sufficiently harmful that we want to provide good warnings to people to take care with cannabis. Avoid use if you're under 21; avoid heavy and prolonged use; seek help early if you're having trouble. When campaigners claim cannabis is a harmless herb they make it much harder for people like me who are trying to get it legalised and regulated.