Weed smokers have no increased risk of depression or psychosis, study says

Good news, teenage weed smokers. You're no more likely to suffer from depression, anxiety, psychosis or asthma than anyone else.

That's according to a new study from the United States, which tracked under-18s with 'chronic' marijuana usage (regular usage each week) over the course of two decades. It follows a number of US states legalising the drug, while a petition for a similar measure in the UK received more than 150,000 signatures. Researchers tested a sample of 408 men, following them from age 14 to 36. They tracked early chronic users as well as those who only smoked as teenagers, those who began smoking later and continued into adulthood, and those with low or no marijuana usage. One researcher, Jordan Bechtold from the University of Pittsburgh, described the results as "surprising". But he admitted  "continued data collection and longer follow-ups are needed" to provide more detailed results.