. Author manuscript; available in PMC: 2010 Jul 1.

Published in final edited form as: Psychopharmacology (Berl). 2009 Feb 25;204(4):573–585. doi: 10.1007/s00213-009-1489-4

Table 2.

Interpretation of differences between the experimental conditions

Measure^a	Withdrawal	Acute Caffeine Effects^b	Chronic Caffeine Effects^c	Tolerance
Doppler
Middle Cerebral Artery
Mean Velocity	X^d, ^e, ^f	X
Systolic Velocity	X^d, ^e, ^f	X
Diastolic Velocity	X^d, ^e, ^f
Pulsatility Index	X^d, ^e, ^f
Anterior Cerebral Artery
Mean Velocity	X^e, ^f	X
Systolic Velocity	X^e, ^f	X
Diastolic Velocity	X^e, ^f	X
EEG
Relative Theta	X^d, ^e, ^f
Relative Beta2	X^e	X	X
Withdrawal Questionnaire
Tired	X^d, ^f
POMS
Vigor Scale				X^g, ^h
Fatigue Scale		X
Friendly		X		X^g, ^h
Lively		X		X^g, ^h
Energetic	X^d, ^f	X		X^g, ^h
Fatigue	X^e, ^f	X
Sluggish
Weary	X^d, ^f	X		X^g, ^h
Efficient				X^g
Full of Pep		X		X^g, ^h
Bushed		X		X^g, ^h

Column 1 lists dependent measures that had significant main effects in the ANOVA

Column 3 shows which measures demonstrated evidence of acute caffeine effects (significant difference between Plac/Caff and Plac/Plac)

Column 4 shows which measures demonstrated evidence of chronic caffeine effects (significant difference between Caff/Caff and Plac/Plac)

Significant difference between Caff/Plac and Plac/Plac (a conservative test of withdrawal)

Significant difference between Caff/Plac and Caff/Caff (a test of naturalistic withdrawal)

Significant difference between Caff/Plac and combined chronic maintenance conditions (Caff/Caff, Plac/Plac) (an overall test of withdrawal)

Significant difference between Plac/Caff and Caff/Caff (a test of tolerance)

Significant difference between Plac/Caff and Caff/Caff AND no significant difference between Caff/Caff and Plac/Plac (a test of “complete tolerance” development for those measures)