Buprenorphine anti-depressant action

[Politicalchalk]

SWIM's been on Suboxone, a high-dose sublingual buprenorphine preparation for about a year now. He's also got bi-polar disorder. He tried a rather fast downward titration recently, and also experienced a psychotic episode and a bad depression streak around the same time. He has since gotten much better and has resumed the full dose (16mg) of buprenorphine. He's on no anti-depressants, per se.

SWIM has read about this drug having some unique anti-depressant actions. He wonders if anyone knows to what extant (if any) buprenorphine acts on serotonin centers? Could the anti-depressant action be "caused" by it's strong binding affinity for the kappa opiate receptor (as opposed to mu, which is where the euphoria is thought to come from)?

Oh, and he wanted you to know he was prescribed Suboxone for opiate addiction (pain killers). This preparation is thought only to curb withdrawal symptoms, and not cause euphoria. Buprenorphine is also the active drug in Temgesic.