Does having divorced or separated parents increase the actual risk of ADHD?

Not as a direct cause, no, though divorce and ADHD can genuinely intersect in ways worth understanding. There's no strong evidence that parental separation itself causes ADHD, which has a well-established genetic basis, but family stress can affect how symptoms present and how well a child copes, and undiagnosed ADHD in a parent or child can itself contribute to family stress and conflict. The relationship, where it exists in research, tends to run through stress and disrupted routine affecting symptom visibility and severity, not through divorce creating the underlying condition. References: https://www.caddra.ca/wp-content/uploads/Canadian-ADHD-Practice-Guidelines-4.1-January-6-2021.pdf