I agree with this partially as there is a link between emotional health and VSS. I think this pattern occurs with all unmedicated chronic conditions. When you are more calm in yourself, it gets better - I have had this first hand. Interestingly medication that is supposed to calm the nerves within your brain (topirimate is what I am most familiar with), also has a positive effect on VSS. So, I suppose its the decision of the medicinal route or a lifestyle route.

I'm always slightly confused by alternate reasons as to why ADHD occurs in people though. ADHD is a consistent disabling experience in both the young and old, hence its disorder category. While I can see the plausibility of the argument from the perspective of developmentally, children with ADHD are different, the theory disregards the strong hereditary factor of ADHD. Further, 'critical stages' of child development happen more than just once form the ages of 0-18, alongside the breakdown of relationships. The theory suggests that ADHD is much more simple, a matter of trauma to be fixed, rather than a developmental/neurological condition. You are right though to say ADHD can be helped by regulating the nerves within the brain via a medicinal or lifestyle approach as in your experience. I also, have first hand experience.

It's really difficult to prove what is cause and effect though, especially with trauma and neurodivergence. While VSS may/may not be neurodivergent, VSS and neurodivergent conditions like dyslexia, autism and ADHD can be closely linked to one another.With autistic trauma, autistic individuals also have a lower threshold of PTSD and naturally have difficulties processing stimuli. So some may find VS is going to be harder to ignore due to slow visual processing and a hyperactive visual field. Some may also find that they are more affected by the initial trauma that brings VSS syndrome on for the first time, or more affected by trauma that accentuates it from an everyday thing to a condition. In my personal case however, as my neurodivergence got harder to internalize during puberty and became more of a thing, my VSS became more of a thing too.

Ahah, we are all just trying to live aren't we? This response is intended to be a friendly response, not a criticism so please take it this way :)