Saudi Arabia has one of the most strict laws regarding drugs, Smuggling drugs to Saudi Arabia is punished by capital punishment, and dealing drugs is punished for first offense to be 2-15 years in prison, repeating offenders are possible to get the capital punishment too, it's up to the judge, he has an authority to bestow a punishment that it is not written in the law books (تعزير) , and for users 6 months in jail unless if you go by yourself to a hospital and they will get care for you, it's free of charge since medical care is free in Saudi Arabia.
But there's a city in the province of Jazan called Fayfa (the population is 359,000) where khat;qat (قات) is grown and sold, it's a controlled substance in the U. S. U. K. Germany and Canada and of course Saudi Arabia.
Fayfa has borders with Yemen, a country that's famous with qat, it is widely used there and it's legal, and they had an effect on it. It's still prohibited to smuggle qat though.