I was on moclobemide some years ago, up to max recommended dosage of 600mg/d, had high hopes for it because MAOIs are usually labelled as the gold standard in antidepressants but it was a complete disappointment. The only noticeable effect was brain fog, I felt stupid. MAO inhibition was working as I challenged it with a micro dose of d-amphetamine which increased my blood pressure notably. Guess the problem is that serotonin by itself isn't even that mood lifting but things work downstream through some cascades involving oxytocin and various other transmitters I don't fully understand anything, the more I learn the more I realize that I and maybe even we all barely know a thing. Woulda help if doctors could accept that.
But others get great relief from moclobemide.
What really worked for me was the research chemical 4,4'-dimethylaminorex, which is a serotonin-dopamine-releaser and slight MAOI - the latter property protected to some degree against 5-HT depletion and it worked again and again over some days without hangover and after like 10 days 75mg venlafaxine was enough to take all remaining symptoms. So I dunno what's the deal with moclobemide, if it is because it's reversible or maybe has low affinity and can get displaced by serotonin.
I'm somewhat interested in harm(al)ine alkaloids, these are reversible MAOIs too and e.g. tobacco contains them. Interestingly no smoker ever got serotonin syndrome, during some time I also used snorting tobacco (snuff) which is more intense and less carcinogen than regular cigs, the effect is remarkably different from pure nicotine as in vaping devices or nicorette gums, which I attribute to the MAOI chemicals. One thing I wanna do is making a liquid with low nicotine + harmaline, maybe recreating a more similar experience because nicotine alone was so useless to me that I quit, relativelt painlessly so, just when I smell smoke or see somebody lighting one, from time to time I get the cravings but remembering then what nasty carcinogens I'd inhale with the smoke helps getting over the urges.
There's a slight possibility that I should have dosed higher with the moclobemide, today I'd just try it but back then I was more obeying to authorities, lol. No, it's of course good human sense not to blindly overdose drugs. But metabolism differs heavily between individuals and so does tolerance. Said 4,4'-dimethylaminorex could easily have killed me, when it came out first it wasn't known that it hits MAO and people who thought it was bunk because of like 2-3h come up time, took another pill and some of them died horribly. So my venlafaxine while still remainders in my system.. ugh. And today my tolerance to serotonin is even higher as I've been on venlafaxine for the last like 6 years and now switched to fluoxetine in the hope of withdrawing it but just 2 days without and I get intense dysphoric restless brain-zaps..
Also the moclobemide didn't have any withdrawal symptoms, afair I took it for at least one month. It doesn't take away the symptoms from SSRI w/d either, which is a bit strange as SERT appears to be limited in respect of tolerance, it's more receptor downregulation happening (and there seemingly most important 5ht1a) and thus a MAOI should help...
Unfortunately I don't see benefits to ADHD, there you'd need something like parnate probably, which also hits dopamine and/or norepinephrine.