title: Development of the caffeine withdrawal symptom questionnaire: caffeine withdrawal symptoms cluster into 7 factors.
abstract: BACKGROUND
  Habitual caffeine consumers who abstain from caffeine experience withdrawal symptoms such as headache, fatigue, difficulty concentrating, mood disturbances, and flu-like symptoms (Juliano and Griffiths, 2004). The caffeine withdrawal syndrome has been documented across many experimental studies; however, little is known about how withdrawal symptoms co-vary during a discrete episode. Furthermore, a validated measure of caffeine withdrawal is lacking.
  
  
  OBJECTIVE
  To develop, evaluate, and reduce a 23-item measure of caffeine withdrawal symptoms; the Caffeine Withdrawal Symptom Questionnaire (CWSQ), to a set of composite variables.
  
  
  METHODS
  Caffeine consumers (N=213) completed the CWSQ after 16h of caffeine abstinence. A subset of participants also completed the CWSQ during a preceding baseline period and/or after double-blind consumption of caffeinated coffee.
  
  
  RESULTS
  Principal components analysis resulted in a solution comprised of 7-factors: (1) Fatigue/drowsiness; (2) Low alertness/difficulty concentrating; (3) Mood disturbances; (4) Low sociability/motivation to work; (5) Nausea/upset stomach; (6) Flu-like feelings; and (7) Headache. With the exception of nausea/upset stomach, the CWSQ total score and individual composite scores were significantly greater during caffeine abstinence relative to both baseline and double-blind consumption of caffeinated coffee, thereby demonstrating sensitivity of the measure. Compared to non-daily coffee consumers, daily consumers had greater increases in total withdrawal, fatigue/drowsiness, low alertness/difficulty concentrating, mood disturbances, and headache.
  
  
  CONCLUSIONS
  Future directions include replication, assessment on a clinical population, and further examination of psychometric properties of the CWSQ. The CWSQ should facilitate the assessment and diagnosis of caffeine withdrawal and increase our knowledge of the caffeine withdrawal syndrome.
authors.affiliation: Department of Psychology, American University, Washington, DC 20016, USA. juliano@american.edu
authors.forename: Laura M
authors.initials: LM
authors.lastname: Juliano
authors.forename: Edward D
authors.initials: ED
authors.lastname: Huntley
authors.forename: Paul T
authors.initials: PT
authors.lastname: Harrell
authors.forename: Ashley T
authors.initials: AT
authors.lastname: Westerman
mesh_terms: D000293:Adolescent; D000328:Adult; D000339:Affect / Q000187:drug effects; D001143:Arousal / Q000187:drug effects; D002110:Caffeine / Q000009:adverse effects* / Q000494:pharmacology; D016000:Cluster Analysis; D003069:Coffee / Q000009:adverse effects*; D005221:Fatigue / Q000139:chemically induced*; D005260:Female; D006261:Headache / Q000139:chemically induced*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009042:Motivation / Q000187:drug effects; D025341:Principal Component Analysis; D011597:Psychomotor Performance / Q000187:drug effects; D011619:Psychotropic Drugs / Q000009:adverse effects* / Q000494:pharmacology; D013375:Substance Withdrawal Syndrome / Q000175:diagnosis*; D011795:Surveys and Questionnaires
chemical_list: D003069:Coffee; D011619:Psychotropic Drugs; D002110:Caffeine