During my graduation, I along with my group undertook a research project on 'Impact of migration on drug use/abuse. This was our persistent belief that migration does play a significant role in falling prey to drug use/abuse and we wanted to test our hypothesis. The results were quite positive as per our hypothesis.
Actually, there are quite a factors which are complimentary to migration be it any sought of migration except 'step wise migration and gradual shifts'. The factors like increased independence, stress etc. especially in upward migration ( from city to town then to city etc. ) are conducive conditions for the development of habits like drug use and even abuse. It is quite affirm with the individuals migrations. The major drug markets which you will see in the world are mostly the famous tourist spots or the places where people usually migrate for job, education and settlement etc. Also, developing or underdeveloped populated cities are the major hubs of this as these also have a big market of migrant or tourist individuals and families. This is one of the major reason behind this.
Now, coming to the topic, legalizing drugs, in my opinion is a better step. Legalization of drugs will help in more regulations and transparency in this ever present unregulated industry. And the major customers of drug addictions (migrant/tourist population) will can be better advised or informed on this particular habit as all the drugs in their every type of dose are not harmful. There are some drugs which under specific advisory are also medically helpful, like in preventing stress etc.