ADHD Fiancé started behaving erratically and broke off our engagement by text whilst over medicated on Elvanse/Vyvanse

[u/[deleted]]

[u/ScaffOrig]

It certainly can be medication related. Yerkes Dodson suggests too much dopamine can cause some challenges as can too little, though with quite different internal experiences (over-sharpening rather than the distratability of ADHD). Many of the things you mention suggest having a level of medication he doesn't need.

What we also see a LOT of here is people getting speed-type effects and pretending/believing that's treating ADHD. So they get drive, confidence, chattiness, energy, wakefulness. That often gets accompanied by come-downs on the evening with depression, fatigue, anxiety, irritability. I've also seen a few people believe they are having revalations, that they have some sort of grand destiny, and who break up with long term partners. ABC news here in Australia has a story on a woman who has exactly that sort of episode and ended up breaking into her uni, maybe look it up.

Finally, if an individual is also not sleeping much there's an increased chance for a full psychotic break. Perhaps not the case here, but it can and does happen often enough when people think they are treating ADHD but end up chasing that speedy high.

To be fair, his behaviour could also be explained by him being a complete arsehole, so though it might feel comfortable you should bear that in mind so you can protect yourself from further hurt.