I think it's terrible, which is why I think rapid titration makes little sense for psych applications. I agree that's horrible and I hope no one is espousing otherwise.
Here's the thing. A dermatologist once told me, that while many don't probably fully appreciate this, not only is the skin its own organ, but it's also a big extension of the immune system, and a finnicky not-well-understood part at that. Just about everything shows up in skin, eventually. I mean, why do so many disparate viruses with varying and seemingly unrelated symptoms cause rash? It's a big immune organ.
As such, anything you ingest has the potential to trigger some nasty skin stuff. Drugs in particular are somewhat foreign agents to the body, and so they're best candidates for triggering immune weirdness and skin sx. Just about every drug has the potential to trigger SJS/TENS or DRESS. Some more than others for various reasons.
I was told that steady dose lamotrigine, even at high doses, isn't actually among the worst culprits for causing dangerous skin reactions. Keeping in mind that across the board we're still talking rare enough that people use them anyway.
What isn't well understood, is why it is that the rapidity of the change of concentration seems to be the trigger. Which means that people should also be cautious coming off it, but rarely are. Something about that change seems to be what sets the immune system, specifically in the skin, off. Fascinating. Why this drug more than others? Why isn't it dose-related? Ie, why is a slow titration from 400-->500 less likely to set it off than a rapid titration from 100-->200 ? No one knows.
I don't have data on this, but I know I've seen numbers and examples to compare.
So my personal conclusion is that the real danger in lamotrigine has to do with the change in plasma concentration over time, so go slow.
There's tons of things that patients could "do without" that we unhesitatingly give them every day, that could do something similarly horrible and irreversible or deadly, and I'm certain a lot of that has similar risk and probably examples that are even higher. Factor it into to management of anything, certainly. Anything in medicine that is an "exception" to business as usual gets more attention, and it should. That's not always the same as more dangerous.