RATIONALE:

Abrupt cessation of caffeine often results in several withdrawal symptoms among habitual caffeine consumers.

OBJECTIVE:

The objective of the study was to determine whether caffeine withdrawal symptoms co-exist as clusters in some individuals.

MATERIALS AND METHODS:

Withdrawal symptoms and caffeine intake were assessed for men (n=126) and women (n=369), aged 20-29, using a caffeine habits questionnaire and a semi-quantitative food frequency questionnaire, respectively. Principal components factor analysis was used to identify common underlying factors among 14 well-described caffeine withdrawal symptoms. Odds ratios (OR) and 95% confidence intervals (CI) were calculated to determine if the likelihood of reporting a withdrawal factor was associated with habitual caffeine consumption.

RESULTS:

The 14 withdrawal symptoms were grouped into three factors termed "fatigue and headache", "dysphoric mood", and "flu-like somatic". The likelihood of reporting the fatigue and headache and dysphoric mood factors increased with higher levels of habitual caffeine consumption. Compared to <100 mg/day of caffeine, the ORs (95% CI) of reporting the fatigue and headache factor with a habitual intake of 100-200 mg/day and >200 mg/day were 1.97 (1.21, 3.21) and 4.44 (2.50, 7.86), respectively. The corresponding ORs (95% CI) for the dysphoric mood factor were 1.55 (0.96, 2.52) and 3.34 (1.99, 5.60).

CONCLUSIONS:

The 14 well-described caffeine withdrawal symptoms factor into three clusters, suggesting the existence of three distinct underlying mechanisms of caffeine withdrawal. Increasing habitual caffeine consumption is associated with an increased likelihood of reporting the fatigue and headache and dysphoric mood symptoms, but not the flu-like somatic symptoms.