Smoking cannabis leads to lung damage, but in a different way to tobacco, finds a new research. The report from the long-running Dunedin Multidisciplinary Health and Development Study, which documented cannabis use and measured lung function throughout adult life up to age 45 in more than 1,000 individuals born in Dunedin, New Zealand in 1972-73, revealed that prolonged cannabis use led to over-inflated lungs and increased the resistance to airflow to a greater extent than tobacco.