I gave up caffeine (tapered off to one cup, was at 6 cups a day and I’m a small human) and I almost immediately noticed my anxiety levels cut by 75%. In terms of sleep, I didn’t notice a huge difference, but I also am not good about setting a calming routine before bed. If caffeine is playing a large role in your insomnia you should feel more able to fall asleep quite quickly . Caffeine can greatly increase cortisol levels and sometimes that can take some time to come down