Panic Disorder and Chronic Caffeine Use: A Case-control Study.

Background: Acute administration of caffeine produces panic attacks in most Panic Disorder (PD) patients, but little is known about chronic caffeine use in these patients.

Objective: To assess caffeine use in patients with PD and to ascertain if caffeine consumption is associated with sociodemographic or clinical features.

Methods: 65 adults with PD and 66 healthy controls were included in the current study. Their caffeine intake within the previous week was quantified with a questionnaire and compared. Harmful caffeine use was defined as consumption above 400 mg/day of caffeine. We tested for correlations between caffeine intake, demographic and clinical features.

Results: Patients consumed significantly more caffeine than controls (P < 0.001). 14% (N = 9) of the PD patients made harmful use of caffeine. The use of caffeine-containing medications was observed in 40% (N = 26) of the PD patients and 6% (N = 4) of controls. Consumption of energy drinks was observed in 11% (N = 7) of PD patients and in none of the healthy subjects. Patients reported sleeping significantly less than controls (P < 0.001). In PD patients, caffeine consumption was not correlated with the presence of panic attacks or comorbidity with depression. The use of benzodiazepines or sedative medications was not correlated with caffeine intake.

Conclusion: High caffeine consumption in PD patients could be explained by the development of tolerance with regular use of this substance. Subtypes of sensitive and non-sensitive PD patients could also explain why some of these patients are able to tolerate high doses of caffeine.