Side effects - Is daily Methadone use bad for people with depressive problems?

[baron samedi]

SWIM has heard from many sources that methadone is one of the least euphoric opioids about (hence its use in opiate maintenance programmes).
SWIM has very little knowlege of opioid pharmacology (mu, delta, kappa), but believes that opioids which are kappa agonists can actually produce dysphoria or general misery. Is methadone one such opioid?
Certainly since switching from poppy pods (opium in other words) to methadone, much of the euphoria he was experiencing from poppies seems to have disappeared and much of the time SWIM feels utterly misarable, despite also taking high doses of SSRI's. One of his thoughts is that a higher dose of methadone (60ml or above) might actually help, because when his dose has been increased in the past it has led to a few weeks of positive thinking. On the other hand he now wonders whether or not methadone could be accentuating SWIM's dysphoria. SWIM is anhedonic anyway (can't experience natural pleasure like most people) so maybe methadone is the last drug he should be looking at for this particular symptom (presuming it is a kappa agonist).
Could buprenorphine be a better option for SWIM in this case, given that it can have an anti-depressant action in some people?