Re: Pot
Cannabis, like many other drugs has both benefits and disadvantages. Cannabis has been shown to be extremely beneficial in terms of pain relief -especially in cases of severe arthritis etc. Occasional use is also pretty harmless (except in my experience it transforms people into very boring individuals).
Its real dangers lie in its use by young people. It can cause lack of motivation, loss of enthusiasm and loss of the ability to concentrate, so that it can be pretty disastrous for young cannabis users who should be concentrating on their education and exams. In my career as a youth worker I saw dozens and dozens of young people whose career prospects were seriously damaged by their regular use of cannabis. Even more seriously, there is increasing evidence that high levels of cannabis use at a young age can increase the likelihood of people developing psychiatric disorders as a result. Anxiety disorders are very common and research is now linking heavy cannabis use (as teenagers) with the development of paranoid schizophrenia amongst young adults.
Purely as anecdotal evidence, amongst a group of 12 young men I worked with in the early 90's, 5 have been treated for serious anxiety disorders and 4 have been sectioned with a diagnosis of paranoid schizophrenia. All those young men were obsessive cannabis smokers from the age of 14 to 25 (when their symptoms began to appear).