Let me preface this by saying I fully support the legalization of both medical and recreational use of cannabis. However, people who say you can't experience physical withdrawal symptoms are lying to themselves. I've had to stop smoking for extended periods of time for jobs and drug tests and I've experienced some of the worst night terrors, panic attacks, and irregular heart palpitations during those times. I have no family history of any of these symptoms so it was clearly brought on by the halt in marijuana use.