Viimase kanepiuuringu ebaadekvaatne tõlgendus

Nädala alguses sattusin kuulama hommikul raadiot, kui vist Olaf Suuder ja Henrik Roonemaa viimast kanepiuuringut kommenteerisid ja sisuliselt seda sama rääkisid, mis kirjas Päevalehe uudistenupus Teadlased: kanepi suitsetamine põhjustab skisofreeniat.

Kahjuks on meditsiinilised ja epidemioloogilised uuringud väga sõltuvad statistikast ja tõenäosustest, mis võib valdkonda mitte tundvad inimesed kiiresti eksitavate järeldusteni viia. Õnneks on suuremate ajalehtede juures meditsiini küsimustele spetsialiseerunud ajakirjanike, kes teavad, milliseid täpsustavaid küsimusi esitada ja kuidas uurimust tõlgendada:

If marijuana produces what seems like such a large jump in risk for schizophrenia, have schizophrenia rates increased in line with marijuana use rates? A quick search of Medline shows that this is not the case-- in fact, as I noted here earlier, some experts think they may actually have fallen. Around the world, roughly 1% of the population has schizophrenia (and another 2% or so have other psychotic disorders), and this proportion doesn’t seem to change much. It is not correlated with population use rates of marijuana.

Ainuüksi see täpsustus peaks juba uurimuse perspektiivi panema, kuid lisaks heidab postituse autor Maia Szalavitz pilgu ka tõenäosuste tõlgendamisele epidemioloogias:

Very little of the coverage put the risk in context. A 40% increase in risk sounds scary, and this was the risk linked to trying marijuana once, not to heavy use. To epidemiologists a 40% increase is not especially noteworthy-- they usually don’t find risk factors worth worrying about until the number hits at least 200% and some major journals won’t publish studies unless the risk is 300 or even 400%. The marijuana paper did find that heavy use increased risk by 200-300%, but that’s hardly as sexy as try marijuana once, increase your risk of schizophrenia by nearly half!

By contrast, one study found that alcohol has been found to increase the risk of psychosis by 800% for men and 300% for women. Although this study was not a meta-analysis (which looks at multiple studies, as the marijuana research did), it certainly is worth citing to help readers get a sense of the magnitude of the risk in comparison with other drugs linked to psychosis.

Kas see tähendab, et kanep on ohutu? Tõenäoliselt mitte, kuid kindlasti näitab see seda, et teemat kajastavad inimesed lähtuvad rohkem enda isiklikest eelarvamustest kui sellest, mis uurimuses tegelikult kirjas.

Maia on ka varem "kanepihullusest" kirjutanud ja seda üpriski paljastavalt Saloni jaoks.

Ma ei tee sellest mingit saladust, et pooldan narkootikumide legaliseerimist. Miks täpselt võib lugeda siit.