All my life I have had a very high tolerance to medications. It is a trait that runs in my mom's side of the family. I have also noticed I never go through withdrawals when I stop taking medications such as anti-depressants and opioids. I have been taking 120mg of methadone a day for about 9 or 10 months. I stopped taking it cold turkey for 4 days and I never had any withdrawal symptoms. In fact, by the 3rd and 4th days I was feeling more mentally and physically energized than I had in months. Other than my chronic nerve pain condition getting more painful, I felt great. By the 5th day I finally got my perscription filled so i started taking it again. But what does it mean that I did not have any withdrawal symptoms? Was I not off it long enough? Or do some people just lack whatever causes withdrawal?