Tramadol
"Tramadol does two things - relieve pain and alter mood.  It affects opioid receptors in the brain and gut, and acts in the same way as a serotonin uptake SSRI / SNRI drug.  So, it makes you feel good and acts like an anti-depressant.  For short term use (very short) it's useful, but it is highly addictive in spite of what the docs and FDA say.  The withdrawals are insanely awful if you have taken it for more than a week or so - since you are withdrawing from an opiate and an anti-depressant.  Unbelievably, medical professionals are still prescribing this drug as non-addictive and non-habit forming.  If you have serious pain - take opiates - resist any attempt to give you this drug."