You need something like 14 days for caffeine withdrawal to cease (during which anxiety may temporarily increase). And any effect from changing things about migh

You need something like 14 days for caffeine withdrawal to cease (during which anxiety may temporarily increase). And any effect from changing things about might take weeks to have an effect on anxiety (perhaps up to 6-12 weeks). Exercise (if tolerated) can have an effect in about two hours, and I've read papers which suggest some prescribed (and indicated) medications can have an effect in around 3 hours. But withdrawing stimulants such as caffeine, although essential to long term recovery, generally doesn't have a sudden effect. Similarly, some standard treatments for anxiety actually increase symptoms in the short term (e.g. patients who were given sedative antihistamines in the past, which are no longer recommended as a treatment, used to be advised that their symptoms may initially increase).