Yet no insurance company will provide me with health insurance because I've taken ADHD medication within the last five years

If I stop taking my meds and let my mental health deteriorate for five years, they apparently think I'm less likely to be a net expense for them

What country is this?

Usually when I hear about health insurance being unreasonable, it's the united States. However, denying health insurance for a pre existing condition is illegal in the United States under the affordable care act, and I'm not aware of any exception to this that would explain your situation.