I've seen conflicting opinions on this. Some say towards the end of the war he was absolutely addicted to opioids and other drugs whilst others say the man was clean and wouldn't even smoke. As someone who specialises in psychology and studies it the accounts on his personality and who he was would not suggest an addiction or the need to ever take drugs. Yet there are many personal accounts of people close to Hitler claiming his excessive use.
There is always more to say, but this topic comes up at AH semi-regularly, and you might like to review this earlier answer by u/commiespaceinvader while you are waiting for fresh answers to your query: