How does COVID stress vary across the anxiety-related disorders? Assessing factorial invariance and changes in COVID Stress Scale scores during the pandemic

•COVID Stress Scales show factorial invariance across anxiety-related disorders, mood disorders, and no disorders groups.•COVID stress tended to be highest in people with anxiety-related and mood disorders, particularly panic disorder.•COVID stress fluctuated over time, being higher early in the pandemic when threat was greatest and lower during the later phases.