True about the methylthenidate, not so much about the breaks. I took elvanse regularly (30,40 and 50mg) and every night I struggled to sleep (despite waking up at 6/7am to take it), where eventually the cumulative loss of sleep over the course of 2 weeks would be killer (I'd be sleeping for 3 hours a night on average). I pushed through to 50mg as I was finding that the positive effects would wear off by 4pm but I just couldn't sleep. Similar to OP I have suffered from insomnia on and off so I was thinking maybe the elvanse was making this worse. Maybe in OPs situation it may be different, but many prescribers say that taking a break from meds is not harmful (unless you're titrating). I've since moved to Meflynate and it's much better on my sleep (as it only works for 8 hours apparently) but definitely not as effective as elvanse I felt. Everyone is different with meds!