Can long term tramadol permanently deplete my serotonin?

Most people are surprised to learn that depression is not caused by a 'chemical imbalance' related to serotonin or any other neurotransmitter.  Actually, the chemical imbalance concept was originally a marketing strategy.  Chemical imbalances aside, depression that people experience when stopping opiates can sometimes be severe and may be associated with suicidality.  You describe a significant depression that has already improved.  Sometimes with severe withdrawal depression an antidepressant is needed.  If your depression has improved significantly the antidepressant is not needed.  I typically avoid prescribing any medications when people withdraw from medications because over time the prescribed medication may well become a problem.  When patients have mild to moderate depression I often recommend a supplement, SAM-e at a 400 mg daily dosage along with b-complex.  This facilitates synthesis of neurotransmitters and has a proven track record in helping depression.