I mostly caught the part where the guy I replied to was making ridiculous statements about both antidepressants and how there is somehow a "logic" which dictates that illegal substances can't treat depression.
What I said was that it is completely illogical to say that because you think heroin can fight depression and its also addictive and destructive, that therefore real anti-depressants must also be addictive and destructive. You cannot infer the properties of anti-depressants from the properties of a bunch of illegal drugs that you (a lay person) consider to have anti-depressant properties.
Actually, while not really addictive, virtually all anti-depressant/anti-anxiety drugs turned out to be habit forming, to pharma corps dismay and nobodies surprise.