Study Title and Description
Development of the caffeine withdrawal symptom questionnaire: caffeine withdrawal symptoms cluster into 7 factors.
Key Questions Addressed
|1||For [population], is caffeine intake above [exposure dose], compared to intakes [exposure dose] or less, associated with adverse effects on behavior*?|
Primary Publication Information
|Title||Development of the caffeine withdrawal symptom questionnaire: caffeine withdrawal symptoms cluster into 7 factors.|
|Author||LM Juliano,ED Huntley,PT Harrell,AT Westerman,|
Secondary Publication Information
There are currently no secondary publications defined for this study.
Extraction Form: Behavior - Design Details - INCLUDED Studies
No arms have been defined in this extraction form.
|Question... Follow Up||Answer||Follow-up Answer|
|What outcome is being evaluated in this paper?||Behavior|
|What is the objective of the study (as reported by the authors)?||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.|
|Provide a general description of the methods as reported by the authors. Information should be extracted based on relevance to the SR (i.e., caffeine related methods)||Participants were 213 adults (65% female, 81% Caucasian) with a mean age of 24 (SD 7.8, range 18–64 yrs) recruited from American University and the Washington, DC metropolitan area via flyers and web-based advertisements seeking coffee drinkers to participate in paid research. This sample size was chosen based on the recommendation of 10 participants per item ratio suggested for instrument analysis (DeVellis, 2003; Nunnally and Bernstein, 1994). To be eligible, participants had to consume caffeinated coffee at least 5 days per week for the past year. Mean caffeine consumption was 550.0 mg per day (SD 286.2). All participants were given dietary restrictions that required abstinence from all caffeinated products and were informed that saliva would be collected to verify compliance with the abstinence instructions. All participants (N = 213) completed the CWSQ and craving questionnaire after 16 h of caffeine abstinence. Following the abstinence assessment point, a subset of participants (n = 145) consumed decaffeinated coffee with added caffeine (∼280 mg; decaffeinated coffee (22 g) was prepared with 500 ml of water using a drip coffee-maker. The experimenter added a 28 ml clear solution that was a 1:10 mixture of caffeine anhydrous (Sigma–Aldrich Foundation, St Louis, MO) and water (i.e., 280 mg caffeine). The experimenter was blind to the caffeine content of the vials (i.e., flattened tonic water is used as a placebo in our lab). Participants prepared the coffee based on their preferences and were given 15 min to consume the coffee followed by a 15 min rest period to allow for further caffeine absorption prior to completing the measures under double-blind conditions and again completed the CWSQ and craving questionnaire. The twenty-three items on [the Caffeine Withdrawal Symptom Questionnaire] measure were developed based on caffeine withdrawal symptoms that were identified in a comprehensive review of prior research (Juliano and Griffiths, 2004). Participants were asked to rate each item in terms of how they were feeling at that moment on a 5-pt. scale from 0 (not at all) to 4 (extremely). Eight of the items are positively worded (e.g., energetic) and were reversed scored prior to analyses. PCA was conducted as our goal was to reduce caffeine withdrawal symptoms into a smaller set of composite variables (components) while retaining as much information from the original measured caffeine withdrawal symptoms as possible (Fabrigar et al., 1999; Preacher and MacCallum, 2003). To determine if the CWSQ discriminated between caffeine abstinence and caffeine exposure, CWSQ scores during acute caffeine abstinence were compared to acute caffeine administration using paired samples t-tests.|
|How many outcome-specific endpoints are evaluated?||5|
|What is the (or one of the) endpoint(s) evaluated? (Each endpoint listed separately)||Fatigue/drowsiness|
|List additional health endpoints (separately).||Irritable|
|List additional health endpoints (separately)|
|Notes||The endpoints were a subset of the Caffeine Withdrawal Symptoms Questionnaire and were determined by individual items on the questionnaire; e.g., 'Drowsiness/fatigue' was a composite score determined by ratings of 'drowsy/sleepy', 'tired/fatigued', 'sluggish', and 'yawning'. Other outcomes which were not related to behavior were 'Nausea/upset stomach' and 'flu-like feelings'. A composite score for 'total withdrawal' was also reported but was not included here in order to prevent repeated reporting.|
|What is the study design?||Controlled Trial|
|Randomized or Non-Randomized?||NCT|
|What were the diagnostics or methods used to measure the outcome?||Subjective|
|Optional: Name of Method or short description||Caffeine Withdrawal Symptom Questionnaire|
|Caffeine (general)||Caffeine (general)|
|What was the reference, comparison, or control group(s)? (e.g. high vs low consumption, number of cups, etc.)||Abstinence condition vs. 280 mg caffeine - Study analyzed within-subject differences|
|What were the listed confounders or modifying factors as stated by the authors? (e.g. multi-variable components of models. Copy from methods)||None stated, an irrelevant portion of the study controlled for daily and non-daily caffeine consumption but this was not related to the outcomes described for behavior.|
|Provide a general description of results (as reported by the authors).||As shown in Table 3, participants (n = 145) reported greater total withdrawal, fatigue/drowsiness, low alertness/difficulty concentrating, mood disturbances, low sociability/motivation to work, flu-like feelings, and headache during caffeine abstinence compared to caffeine administration (all p’s < .05). The difference between abstinence and post caffeine administration for the nausea/upset stomach factor was not significant.|
|Did the authors perform a dose-response analysis (or trend/related analysis)?||No|
|What were the authors's observations re: trend analysis?|
|What were the author's conclusions?||The total CWSQ score and all of the factors except for nausea/upset stomach were significantly higher during caffeine abstinence than after double-blind consumption of caffeinated coffee. This provides evidence that the CWSQ can discriminate between periods of caffeine abstinence and caffeine consumption. However, this type of comparison is insufficient to demonstrate that the effects are indeed reflective of caffeine withdrawal, as differences between the two conditions could be a function of caffeine withdrawal, caffeine’s acute pharmacological effects, or a combination (James and Rogers, 2005). However, the total CWSQ score and all of the factors except for nausea/upset stomach were also significantly higher during caffeine abstinence compared to a preceding baseline period in which participants were not exposed to the acute effects of caffeine. Consistent with prior research, these analyses demonstrate that caffeine abstinence produces subjective effects that are significantly more aversive than normal daily experiences.|
|What were the sources of funding?||Funding for this study was provided by the College of Arts and Sciences at American University. The College had no further role in the study.|
|What conflicts of interest were reported?||No conflict declared.|
|Does the exposure (dose) need to be standardized to the SR?||No|
|Provide calculations/conversions for the exposure based on the decision tree in the guide (for all endpoints/exposure levels of interest).|
|List all the endpoint(s) followed by the dose (mg) which will be used in comparison to Nawrot. Characterize value as LOAEL/NOAEL, etc. if possible.||Fatigue/drowsiness NOAEL = 280 mg Low alertness/difficulty concentrating NOAEL = 280 mg Irritable NOAEL = 280 mg Low sociability/motivation to work NOAEL = 280 mg Headache NOAEL = 280 mg|
|Notes regarding selection/listing of endpoints and exposures/doses to be compared to Nawrot.||Study authors set statistical significance at p < 0.05. This study only had caffeine exposure level (280 mg). All behavioral outcomes assessed had a significant within-subject decrease.|
|What is the importance of the study with respect to the adverseness of the outcome?||Important|
No baseline characteristics have been defined for this extraction form.
Results & Comparisons
No Results found.
|Arm or Total||Title||Description||Comments|
No quality dimensions were specified.
No quality rating data was found.