Billions of people rely on caffeine daily to wake up or get through a night shift or an afternoon slump. It is often criticized because of its adverse effects on sleep and anxiety, but caffeine is one of the most commonly used ingredients in the world.
Caffeine, a natural stimulant, is found in tea, coffee, and cacao plants. In addition to keeping you alert and preventing you from becoming tired, it stimulates your brain and central nervous system. Caffeinated products are consumed by over 80% of the world’s population daily, up to 90% of adults in North America.
There has been growing evidence that caffeine has anxiety and panic-inducing properties, particularly in patients with panic disorder (PD). However, the magnitude of caffeine’s impact on anxiety and panic attacks has not been evaluated, nor has the potential dose-response relationship been explored.
The study aimed to examine the acute effects of a placebo-controlled caffeine challenge on panic attacks and subjective anxiety among patients with Parkinson’s disease (PD) and healthy controls (HC) and their dose-response relationship.
The researchers searched six databases, including blinded placebo-controlled studies on panic attacks and subjective anxiety in adult patients with Parkinson’s disease.
A total of ten of the 1893 articles identified met the researchers’ inclusion criteria. Nine studies investigating panic attacks included 237 patients, of whom 51.1% experienced panic attacks after caffeine but none after placebo.
According to six studies comparing 128 patients with 115 healthy controls (HC), patients had a higher risk of panic attacks following caffeine (53.9%) compared to HC (1.7%).
The experts examined the subjective anxiety of 121 patients and 111 healthy controls following caffeine in six studies, which found that the patient group was more sensitive to caffeine’s anxiogenic effects.
In a few studies, the researchers used caffeine at a limited dosage range [400-750 mg], and 480 mg was not used, which prevented meaningful dose-response analyses.
Two of the ten studies included in this meta-analysis reported anxiety data for the placebo condition, so a proper comparison of caffeine and placebo could not be performed. In addition, the limited dose range used made it impossible to assess dose-response relationships.
Results of the Study
This study indicates that many Parkinson’s patients suffer panic attacks at doses roughly equivalent to five cups of coffee, which highly discriminates them from healthy adults.
In addition to increasing anxiety among PD patients, caffeine also increases anxiety in healthy adults at these doses, although it is unclear how caffeine-induced anxiety relates to panic attacks.
Based on the results, caffeine targets pathophysiological mechanisms related to Parkinson’s disease.
“Future studies should employ a wider range of caffeine doses and investigate contributions of biological and psychological mechanisms underlying the anxiogenic and panicogenic effects of caffeine,” – the researchers said.
