To widen the anecdotal data set, I have ADHD and have been using nicotine since I was 16 (29 now). I quit for ~8 months a few years back by making my own vape juice and tapering my nicotine dose down over a period of several months. I never experienced withdrawal symptoms, but my mental health tanked on lower doses and it got even worse when I was completely off nicotine. I was way more irritable, impatient, scatterbrained, and depressed. It was not fun