I believe that marijuana should be legalised for both medicinal and recreational purposes. Whilst marijuana has proven to treat symptoms of a number of different medical conditions, including seizures, anxiety, depression, insomnia, glaucoma etc., legalising marijuana for recreational use would also be beneficial since it is significantly less harmful and dangerous than both alcohol and tobacco.
Additionally, legalising the drug takes it off the streets and into the hands of professionals, making it safer to acquire and improves the quality of the drug, subsequently decreasing any risk factors associated with bad strains. If taxed, the sales would greatly benefit the economy of the country.
However, there should definitely be an age restriction on the consumption of marijuana, either 18 or 21. Not only does this safeguard the brain in its developmental stages by preventing any severe changes to the brain chemistry but it also has a high chance of decreasing dependency on the drug in the long run.