No-one else is affected if someone chooses to use cannabis in private. Drug use has many victims including the families of addicts and innocent people killed by drug-crazed monsters. The NHS must pay for junkies' treatment. The prohibition of any drug is a violation of human and civil rights, an unwanted invasion into privacy and compromises freedom of religion. Drug prohibition is for everybody's good in the long run.
Cannabis has few health risks even when used regularly for long periods.
There are reports of people experiencing cannabis induced mental trauma, called 'cannabis psychosis' There is no evidence that cannabis use itself causes the use of harder drugs. All the evidence suggests that the cause is a personality type. Almost all heroin addicts started with cannabis. It is the first step on the road to hard drug addiction. There is no evidence that Cannabis smoke can contribute to lung damage or increase the risk of lung cancer.