Fellow Garmin user with ADHD.

The HRV status feature on your Garmin is meant to track physiological stress. Not necessarily mental stress (although that can affect physiological things.) Unfortunately yes, when I'm on my ADHD meds (currently unable to source my Adderall XR) my HRV status is lower.

But functionally, I'm better when I'm on my ADHD meds. Yes my body has a heightened stress response (i.e. higher HR during the day when I'm on my meds) from the meds, but in my opinion that's a necessary side effect of the ADHD meds. I'd rather be functional and capable and have a worse HRV than spend hours laying on the floor feeling like I can't function because of my ADHD.

Your HRV status covers a rolling 4-week average. Given enough time on the meds, it will learn your new HRV trends and stop reporting you as "unbalanced." It looks worse than it is right now because the initial period of getting on meds is making it look like your system is out of whack. Which honestly it kind of is, as it's adjusting. Once you figure out the med combo for you, not only will your HRV settle down from getting used to the meds, but the score on your Garmin will also settle down as you spend more time in your "new normal" range.

Basically what I'm saying is: HRV on your Garmin is more intended to track the impact of training and exercise on your body, and not necessarily intended to track how medication changes affect the score. Personally I would take the Garmin readings with that grain of salt: the changes to your score are due to meds rather than exercise, so it's sort of outside the intended use of the feature. Keep up with the meds and keep up with your normal training, but your Daily Suggested Workouts will probably be a bit easier while it recovers from thinking your status is Unbalanced.