Long-term Heavy Cannabis Use : implications for health education Niall COGGANS, Phil DALGARNO, Lindsay JOHNSON & David SHEWAN Drugs : education, prevention and policy, 2004, Vol. 11, No. 4, 299–313   ABSTRACT There is growing evidence that cannabis can have negative effects on health. While the ongoing debate about the nature and duration of these effects recognizes mild cognitive impairment, the evidence for irreversibility of cognitive impairment and causal links with psychiatric illness is not conclusive. There is undoubtedly potential for impairment of respiratory functioning, but that will depend on lifetime load and in most cases is confounded with tobacco smoking. There is a [...]