If they don't go into dormancy, then they'll just keep growing. They do not need it, per se.

To keep your adeniums active throughout the year, you need to keep them warm up to a minimum of 25C and you have to keep them under bright lights using grow lights of about 6500 K and over.

I have read that they do stop producing new leaves sometimes, even in the tropics. But they are not really dormant, their roots grow faster during such periods. I have never observed this personally.

Pagan

P.S. I have 4 adult plants that I have never allowed to go dormant. The rest of my plants are in the basement and even there, only one or two have dropped leaves. The rest have slowed down but only just.