Available online at:
https://cc.arcabc.ca/islandora/object/cc%3Apsycjournal

J Camosun Psyc Res. (2023). Vol. 5(1), pp. 56-77.
Submitted Fall 2022; accepted June 2023.

What Makes Caffeine So Addictive?
Authors: Aliyah Stevens*, Queenie Wang, and Hannah Mawle
Supervising Instructor: Michael Pollock, Psyc 245 (“Drugs & Behavior”)
Department of Psychology, Camosun College, 3100 Foul Bay Road, Victoria, BC, Canada V8P 5J2
*Corresponding author email: astevens1278@gmail.com

ABSTRACT
In this paper, we sought to understand what makes caffeine so addictive, so that we could
learn why it’s so hard to quit. Previous research has found that possible factors which determine
whether caffeine becomes addictive include the amount of caffeine consumed, the expected
pleasure from caffeine, and the degree of withdrawal symptoms when suddenly not drinking
caffeine. In our first (correlational) study, we tested the strength of these relationships by
examining naturalistic daily changes in their variables longitudinally over a period of one week.
We measured the amount of caffeine consumed by self-reporting the number of cups of coffee
that were consumed each day, and measured the expectation of pleasure before drinking coffee,
withdrawal symptoms, and caffeine addiction each on a subjective scale from 0-10. Based on the
strength of correlation found between the amount of caffeine consumed and caffeine wanting, we
then conducted a second (experimental) study to test for a causal relationship between these two
variables. Over a period of one week, we used a within-subjects design and randomly assigned
participants each day to either a caffeinated condition or a non-caffeinated condition using a
double-blind procedure and measured the effect this manipulation had upon wanting caffeine.
Data pooled across participants in our correlational study showed that caffeine wanting was
significantly correlated with the amount of caffeine consumed but not with its expected pleasure
or the degree of withdrawal symptoms. However, data pooled across participants in our
experimental study showed the opposite pattern: increasing caffeine consumption significantly
decreased the amount of caffeine wanting in comparison to the consuming decaffeinated control
condition. This finding means that the more caffeine that is consumed the wanting for caffeine
will decrease. This result sheds light on further research to be conducted between caffeine
consumption and wanting of caffeine.
1. Introduction
1.1 Research Problem
Caffeine withdrawal often causes people
to become irritable and tired. People often
crave coffee and caffeine in the morning and
throughout the day. People often think that
it would be easy to control these urges,

although it can become very difficult to quit.
When people miss a day after being used to
drinking it on a daily basis; it often leads to
withdrawals, making them more dependent
on the substance. We wish to know what
makes caffeine so addictive and why it can
be so hard to quit.

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1.2 Literature Review
One factor previously found to predict the
reason why it is so hard to quit caffeine is
that the more caffeine an individual
consumes the more they want caffeine no
matter how much they like it.For example,
in a study of 56 German students who were
either low/no coffee drinkers (<1 cup daily),
or heavy coffee drinkers (3< cups per day)
by Koranyi et al. (2020), researchers
examined the dissociation between wanting
and liking coffee. Wanting vs. liking coffee
was assessed using two versions of the
Implicit Association Test (IAT) that had
been developed for either assessing wanting
for coffee (W-IAT) or liking of coffee (LIAT). The L-IAT test was comprised of 8
pictures, four coffee-related stimuli and four
juice-related stimuli, which participants had
to assign to either a “coffee” category or a
“juice” category. The W-IAT test was
modified slightly, so participants had to
assign stimuli of either letters or numbers to
their respective categories of either “I want”
in which case participants were incentivized
with a small monetary reward for every
correct and fast answer or “I don’t want”
which was not incentivized, after being
shown stimuli of either coffee or juice.
Participants were split up based on their
reported average coffee consumption (heavy
or low/no coffee drinkers) and answered
both versions of the IAT test. Heavy coffee
consumers were found to have an increased
want for coffee but were similar to low/noncoffee consumers in liking coffee. Based on
these results, the researchers suggested that
individuals with high coffee consumption
crave coffee more than those who do not
drink a lot of coffee, despite how much they
like it.
Another factor previously found to
predict the reason why caffeine is so hard to
quit is that making people feel good is the

reason for the intense cravings and
intentions for caffeine. Such cravings and
intentions are associated with positive
reinforcement expectations that, in turn,
increase caffeine cravings. For example, in a
study of 189 caffeine consumers who
completed a caffeine craving questionnaire
based on the Smoking Impulsivity
Questionnaire (QSU) during one of five
naturally occurring periods of coffee
abstinence by West & Roderique-Davies
(2008), voluntary participants in the study
were university students during lectures and
workshops at the University of Glamorgan.
Participants must complete a questionnaire
containing caffeine consumption,
demographic details, the Leeds Dependence
Questionnaire (LDQ) and the Caffeine
Craving Questionnaire (QCC) in order at the
beginning or end of the lecture or workshop.
The researchers used the Leeds Dependency
Questionnaire (LDQ) to assess participants'
self-rated dependence on caffeine.
Participants were asked to "think about the
last week" and responded on a 4-point scale
including "never," "sometimes," " often,"
and "nearly always." Scores are from "0" for
the lowest dependency to "30" for the
highest dependency. The 32-item Caffeine
Craving Questionnaire (QCC) used by the
researchers was derived from the Smoking
Stimulus Questionnaire (QSU), in which the
items "smoke(ing)" and "cigarettes" were
replaced by the word caffeine. Participants
were asked to respond based on their level
of agreement with each problem statement,
on a scale from 1 (strongly disagree) to 7
(strongly agree), with responses such as
"nothing is better than drinking coffee now"
and "I would if I Now I can drink some
caffeine and I'll be more focused." Before
analyzing all the data from the QCC, the
researchers applied a skew method to rotate
the principal components to produce the
"cleanest" factors and used an independent57

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sample t-test and ANCOVA for data
analysis. The analysis was performed, and
the expected feelings of caffeine were
measured through a three-factor solution
consisting of including Factor 1, reflecting
strong desire, intention and positive
reinforcement; Factor 2, reflecting
mild/general positive and negative
reinforcement; Factor 3, Reflecting negative
reinforcement based on function/mood.
Based on these results, the researchers
suggested that the anticipation of being very
pleasant and strong cravings increase
intentions for caffeine consumption. This is
consistent with significantly higher cravings,
intentions, and desires for caffeine
consumption among participants who selfreported more frequent daily caffeine use.
A third factor previously found to predict
the reason why it is so hard to quit caffeine
is because the withdrawal can display
physical and psychological annoyances
when suddenly no longer taking the drug.
For example, in an experimental study done
on 87 daily coffee drinkers (6 days a week)
that reported their daily caffeine use of 525
mg by Juliano et al. (2019), researchers
examined the psychological influences from
caffeine withdrawal over a 2 day study.
This was done by giving participants a cup
of coffee that was either caffeinated or
decaffeinated (distilled water). Participants
were randomly assigned to groups and were
told they were receiving ‘caffeinated’ coffee
for the day and were either given the
caffeinated coffee or the decaffeinated
coffee. On the second day both the groups
were given decaffeinated coffee with an
added 280 mg caffeine. To measure for the
types of withdrawal symptoms (fatigue, low
motivation, headaches, nausea and flu-like
feelings) participants were asked to fill out
three questionnaires, regarding their
exposure to caffeine (brand, serving, types
of caffeine), withdrawal symptoms they

experience (0-5 scale) whether or not they
would consume the coffee again (0-10 rating
scale). After completing the questionnaires
participants then completed the Rapid Visual
Information Processing test (RVIP) which
was used to measure the participants
attention and cognitive performance from
consuming the caffeinated or decaffeinated
coffee. The participants viewed numbers on
the screen and were told to press the mouse
button on the computer quickly when they
saw odd or even numbers three consecutive
times. Based on these results, the researchers
suggested that those that were given
decaffeinated coffee showed an increase of
reporting flu-like symptoms (nausea,
fatigue, headaches) and also showed poor
cognitive performance. These individuals
also reported much lower scales on the
coffee rating questionnaire than participants
that were given caffeinated coffee and
reported higher scales on the rating
questionnaire. Those with the lower scales
on the coffee rating questionnaire also
reported that they more likely to consume
coffee again, indicating that there were signs
of withdrawal related to their measure of
addiction.
1.3 Hypotheses
Based on the above literature review, we
predicted the following hypotheses:
· Hypothesis #1: If coffee consumption
increases then caffeine wanting will
increase.
· Hypothesis #2: If the expected
pleasure from drinking coffee increases then
caffeine wanting will increase.
· Hypothesis #3: If withdrawal
symptoms increase then caffeine wanting
will increase.

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2. Methods
2.1 Participants
The three authors of this paper served as
the participants in its studies. The
participants ranged in age from 19-49 years
old, with an average age of 19 years, and
included females. The participants were all
undergraduate students at Camosun College
who completed the current studies as an
assignment for Psyc 245 (“Drugs and
Behavior”) and were grouped together due
to their mutual interest in caffeine addiction.
Each of the three participants reported
consuming caffeine on a daily basis.
2.2 Correlational Study Methods
We first performed a correlational study
to test concurrently all of our hypotheses by
examining naturalistic daily changes in their
variables longitudinally. Each participant
kept a study journal with them at all times
over this study’s one-week period in order to
record self-observations of the following
three variables: (1) coffee consumption, (2)
expect the pleasure of drinking coffee, (3)
withdrawal symptoms, and (4) caffeine
addiction/wanting.
Amount of coffee consumption - To
measure coffee consumption, we devised a
questionnaire which included questions
about how many cups of coffee were
consumed each day (see Appendix A for a
complete list of items used in this
questionnaire). Each group member selfreported the number of cups of coffee (1 cup
= 237mL) that were consumed by the end of
each day for a week (7 days).
Anticipated pleasure before drinking
coffee - To measure the pleasure expected
from drinking coffee, we designed a
questionnaire on the level of pleasure
expected before drinking coffee (see
Appendix A for a full list of items used in

this questionnaire). Everyone did this by
self-reporting on a scale of 0-10 how much
pleasure they expected before drinking
coffee (0 being none, 10 being extreme
symptoms). Each team member self-reported
their expected caffeine-induced pleasure for
a week (7 days) before drinking their first
cup of coffee each day. Each of us kept track
of our signs through a daily questionnaire
report.
Withdrawal symptoms - To measure
withdrawal symptoms, we created a
questionnaire containing questions on how
extreme our withdrawal symptoms were (see
Appendix A for a complete list of items used
in this questionnaire). This was done by
each of us self-reporting our symptoms once
a day in the morning before we consumed
caffeine on a scale of 0-10 (0 being not at all
and 10 being extreme symptoms).
Symptoms of headaches, fatigue and flu-like
symptoms were measured before we
consumed caffeine for the day. We each
kept track of our symptoms by reporting
them on the questionnaire daily for a span of
one week (7 days).
Caffeine addiction - To measure caffeine
addiction, we created a questionnaire with a
series of questions regarding how much we
craved caffeine (see Appendix A for a
complete list of items used in the
questionnaire). This was done by each
participant self-reporting how much each
participant craved caffeine once a day for
each day on a scale of 0-10 (0 being no
cravings at all and 10 being extreme). We
kept track of our carvings by reporting them
on the questionnaire daily for a span of one
week (7 days).
2.3 Correlational Study Planned Analyses
To assess the strength and statistical
significance of associations between
variables predicted by our three hypotheses,
we performed Pearson product-moment
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correlations of their predictor variables
coffee consumption, expect the pleasure
before drinking coffee, and withdrawal
symptoms with their outcome variable
increase of caffeine addiction. For testing
Hypothesis #1, we correlated coffee
consumption by analyzing how many cups
of coffee we consumed each day. For testing
Hypothesis #2, we correlated the expectation
of pleasure before drinking coffee on a scale
of 0-10 to get data from the questionnaire
we devised every day. For testing
Hypothesis #3, we correlated withdrawal
symptoms using a scale of 0-10 to be able to
derive a numerical value from the
questionnaire we created. We performed all
of the above correlations separately for each
participant as well as using data pooled
across all of the participants. For the
correlations using pooled data, in addition to
using the raw data, we also performed
correlations after we had first transformed
the data from each participant into z-scores
in order to standardize differences in
averages and variability seen between the
participants in their data and thus make them
more comparable. A correlation coefficient
was considered statistically significant if the
probability of its random occurrence (p) was
< .05 (i.e., less than 5% of the time expected
by chance alone).
2.4 Experimental Study Methods
Based on the strength of the correlation
between the amount of caffeine, along with
the wanting for caffeine found in our
correlational study, we then chose to
conduct an experimental study to test for a
causal relationship between these two
variables from Hypothesis #1.
We manipulated the independent
variable, caffeine amount, over a one-week
period by randomly assigning participants
each day to either a caffeinated coffee
condition or a decaffeinated coffee condition

using a double-blind procedure. Participants
consumed Starbucks caffeinated Pike Place
coffee on experimental days (3 days) and on
control days (3 days) participants consumed
Starbucks Pike Place decaf coffee for a total
of 6 days. To indicate whether or not
participants would be consuming caffeinated
or decaffeinated coffee for the day, they
randomly drew a card with either yes
(caffeinated) or no (decaffeinated) on it.
After consuming the coffee for the day
participants self-reported on a scale of 0-10
their craving on a questionnaire created (see
Appendix B) daily for 6 days.
Participants were randomly assigned to
the experimental or control group each day
to control for order effects. In order to use
the double-blind procedure and control for
placebo effects, participants were unaware
of which condition they were receiving. This
was maintained by having the participants’
friends or family members draw the
corresponding card (yes or no) to perform
the manipulation of the caffeinated or
decaffeinated coffee. The friend or family
member then secretly recorded what
condition was performed which was then
shared at the end of the day after the
participants completed the self-reported
questionnaire for analysis purposes of the
dependent variable. Following this
procedure reduced the experimenter
expectancy effects on the dependent
variable.
2.5 Experimental Study Planned Analyses
To assess the statistical significance of
differences seen in wanting of caffeine on
caffeinated experimental days vs.
decaffeinated control days, Student’s t-tests
were performed. We performed t-tests
separately for each participant as well as
using data pooled across all of the
participants. For the t-tests using pooled
data, in addition to using the raw data, we
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also performed t-tests after we had first
transformed the data from each participant
into z-scores in order to standardize
differences in averages and variability seen
between the participants in their data and
thus make them more comparable. An
average difference between conditions was
considered statistically significant if, using a
one-tailed distribution (i.e., to determine if
there is a difference between groups in a
specific direction), the probability of its
random occurrence (p) was < .05 (i.e., less
than 5% of the time expected by chance
alone).
3. Results
3.1 Correlational Study Results
As shown in Table 1, both anticipated
pleasure and the amount of caffeine were
significantly correlated with wanting of
caffeine. The amount of caffeine consumed
and wanting of caffeine was significantly
correlated for one participant (r = .96, p =
.0002). They were also significantly
correlated using pooled raw data (r = .57, p
= .007; see Figure 1) as well as using pooled
standardized data (r = .44, p = .001; see
Figure 2). Two participants had statistically
significant results for the anticipated
pleasure of caffeine (r = .97, p = .00004; r =0.76, p = .04) and were also significantly
correlated with wanting of caffeine using
pooled raw data (r = .51, p = .01 see Figure
3) but not with pooled standardized data (r =
.13, p = .58; see Figure 4). In contrast,
withdrawal symptom severity and wanting
of caffeine were not statistically significant
using pooled raw data or pooled
standardized data (all r ≥ -.02, all p ≥ .91;
see Figure 5 & 6). Although, two individual
participants had statistically significant
correlations between withdrawal symptom
severity and wanting of caffeine (r = .85, p =

.01; r = -.91, p= .002). Based on the
comparison of the correlation coefficients
using pooled raw data and pooled
standardized data, caffeine amount showed
the strongest correlation with wanting of
caffeine.
3.2 Experimental Study Results
As shown in Table 2, there was a large
difference in the wanting of caffeine
between the caffeinated and decaffeinated
coffee conditions (see Table 2). This
difference was statistically significant using
the pooled raw data shown (t = 5.36, p =
0.00003; in Figure 7) and using the pooled
standardized data (t = 5.66, p = 0.00002; see
Figure 8).
4. Discussion
4.1 Summary of Results
Based on previous research, we
hypothesized that an increase in three
variables would be followed by an increase
in wanting of caffeine: the amount of
caffeine consumption (Hypothesis #1), the
anticipated pleasure of having caffeine
(Hypothesis #2), and the severity of
withdrawal symptoms (Hypothesis #3). Data
pooled across participants in our
correlational study supported the predicted
relationship with caffeine amount
(Hypothesis #1) but not with anticipated
pleasure or withdrawal symptom severity
(Hypotheses #2 & #3). However, in contrast
to our correlational study, findings from our
experimental study showed that an increased
caffeine amount actually decreases caffeine
wanting instead of increasing it.

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4.2 Relation of Results to Past Research
The hypothesis that if coffee
consumption increases then craving or
wanting for coffee will tend to increase is
supported and consistent with past research
on caffeine addiction. Based on the group’s
findings, there is a significant correlation
between caffeine amount and wanting of
caffeine using pooled raw data and pooled
standardized data as seen in Figures 1 and 2.
In past research, participants who reported
drinking more caffeine daily (3+ cups) also
had a greater desire for caffeine (Koryani et
al., 2020). Similarly, this study’s methods
involved participants self-reporting the
amount of caffeine consumed on a daily
basis. The results in the current study are
significant, although in the opposite
direction as increasing coffee consumption
actually decreased wanting of coffee. The
differences in results could be due to a
smaller sample size and/or differences in
methodologies. In past research,
participants were split up based on selfreported caffeine consumption. They were
asked to answer two versions of an Implicit
Association Test to determine the
differences between wanting and liking in
each participant. This method was not used
in the current study, instead, researchers
developed a questionnaire to test all
hypotheses at once with no manipulation
which could be the cause for statistical
inconsistencies. The current study’s results
along with past research suggest that there is
a link between the amount of caffeine
consumed and wanting for caffeine. The
current statistical and nonstatistical results
shed light on explanations for caffeine
addiction and directions for further research.
The results of the experimental study
using a double-blind procedure to determine
the relationship between caffeine amount
and wanting of caffeine revealed similar

results to past research. In past research,
participants who reported drinking heavier
amounts of caffeine daily also had a higher
overall wanting of caffeine (Koryani et al.,
2020). In the current study, participants who
reported having caffeinated coffee reported
having lower cravings of coffee that day.
These results from the current study are
significant in both pooled and standardized
raw data (Figures 7&8). Although there are
methodological differences between the
current study and past research. In past
research, participants were split up based on
average coffee consumption (high and low
consumption) and then asked to complete
two versions of the questionnaire. In the
current study, participants were all
consumers of caffeine already, then each day
were either given caffeinated or
decaffeinated coffee and reported which
condition they got at the end of the day.
These differences could be limiting to the
current study’s results as the two studies
were not outright testing the same
hypothesis. Another limiting factor for the
current study was sample size; the sample
size in this experimental study was three
individuals which means it may not
generalize to the population. However,
despite the differences in the methods, the
results from the current experimental study
were significant, which can shed some light
on future directions of research. If caffeine
consumption is a determining factor on how
much an individual craves caffeine, then
future research can explore ideas such as
why people begin consuming caffeine in the
first place or how an individual can quit
caffeine more easily.
The hypothesis that if the pleasure of
drinking coffee increases, then caffeine
addiction will tend to increase is irrelevant
to past research on caffeine addiction.
Overall the results were not consistent with
past research. According to the group’s
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findings, only two participants had a
significant correlation between expected
caffeine pleasure and caffeine craving. This
suggests that the relationship between
anticipated pleasure and wanting of caffeine
is unlikely since the correlation between the
hypotheses was not significant based on the
pooled standardized data. In past research,
anticipatory caffeine sensations were
measured as reflecting intense desire,
intention, and positive reinforcement of
pleasure and intense craving, predicted to
increase intention to consume caffeine (West
& Roderique-Davies, 2008). Again, the
study's methodology involved participants
self-reporting on a scale of 0-10 how they
expected to be with their daily cup of coffee
before consuming caffeine versus how much
coffee they consumed. However, the results
were not significantly correlated using the
pooled standardized data compared to past
studies, which may be due to
methodological differences. In past research,
participants were asked to respond on a scale
of 1 (strongly disagree) to 7 (strongly agree)
based on how much they agreed with each
question statement, with responses such as
"There is nothing better than drinking coffee
right" Good It's "now" and "If I could drink
some caffeine right now, I'd be more
focused” (West & Roderique-Davies, 2008).
Current data of the participant's recalled
response and the actual amount of caffeine
intake were not significantly correlated. Our
related research results cannot establish a
relationship that exists between anticipated
pleasure and caffeine wanting based on the
pooled data. The present statistical and nonstatistical results shed light on explanations
for caffeine addiction and directions for
further research.
The results of an experimental study
using a double-blind procedure showing the
relationship between caffeine amount and
caffeine wanting were similar to the past

studies. Past research concluded that
cravings for the caffeine element would be
more pronounced in the absence of caffeine
(West & Roderique-Davies, 2008). In this
study, decaffeinated coffee and caffeinated
coffee were randomly ingested using a
double-blind procedure. Participants selfreported their want for caffeine when
receiving decaffeinated coffee compared
with caffeinated coffee much higher, as
shown in Figures 7 and 8. However, this
study has some limitations in that it did not
assess participants' prior caffeine wants and
was conducted on a short number of days.
Caffeine user types may also have been
underrepresented. Therefore, the study's
findings may not generalize to the caffeine
consumer population. However, studies have
revealed a relationship between caffeine
amount and caffeine wanting, which may
increase an individual's chances of
becoming addicted relative to predicting the
frequency and amount of caffeine intake.
For the hypothesis that if withdrawal
symptoms increase then caffeine addiction
will tend to increase does not relate to past
research on caffeine addiction. Based on the
group’s findings only two of the participants
showed significant correlation with
withdrawal severity and the wanting of
caffeine. Withdrawal symptoms showed no
significant correlation in pooled data and
standardized data across the other
hypotheses. In past research participants that
reported signs of withdrawal in the form of
flu-like symptoms (headaches, fatigue and
nausea) were more likely to report that they
would consume coffee again on
questionnaires (Juliano et al., 2019).
Similarly, in the group’s findings the two
participants that reported their symptoms on
a scale of 0-10 before consuming caffeine
also reported an increased wanting of
caffeine. However, the results were not
statistical compared to the past research
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conducted, which could have been due to
methodological differences. In the past study
participants were either given caffeinated or
decaffeinated coffee and then completed the
Rapid Visual Information Processing test
(RVIP) to test for how quickly participants
could respond to numbers on the screen.
This procedure was not used by the
researcher’s, instead a self-reporting
questionnaire was created to test all of the
hypotheses at once correlationally with no
manipulation which may have been the
cause of any discrepancies. Future studies on
caffeine withdrawal could perhaps suggest
new findings if self-reporting questionnaires
are effective or not in measuring caffeine
addiction and if there are other methods that
can be used to report these types of
symptoms accurately. These findings along
with previous research do suggest that more
individuals need to be educated about
caffeine sources and the ability it has to
produce physical dependence and addiction
(Juliano et al., 2019). The statistical and
nonstatistical correlations found in this study
shed light on further research and further
explanations on caffeine addiction. In the
current study we can conclude that
hypothesis #1 (the amount of caffeine
consumption) was confirmed. The scatter
plot in figure 3 presented a positive
correlation with the anticipated pleasure
from caffeine and wanting of caffeine in the
pooled raw data. In the standardized data
shown in figure 4, the positive correlation
between the two hypotheses was not a
reliable measure seen between the
participants. With this data, we can also
conclude that only hypothesis #1 (amount of
caffeine consumption) was statistically
significant using pooled standardized data in
this study. Further research should be done
to investigate correlations between these
variables.

Findings from the experimental study
performed, using a double-blind procedure
to conduct the relationship between the
amount of caffeine and wanting of caffeine
revealed similar results to past research. Past
research has concluded that participants that
were given decaffeinated coffee reported
greater cravings for caffeine than those
given caffeinated coffee (Juliano et al.,
2019). Similarly, in the current study,
participants that received decaffeinated
coffee using the double-blind procedure selfreported much higher wanting for caffeine
compared to when administered caffeinated
coffee. These findings were statistically
significant in both the raw and standardized
pooled data as seen in Figures 7 and 8. In
relation to past research “caffeine craving,
but not coffee craving was also greater
among those told they were drinking decaf
coffee compared with those told caffeine”
(Juliano et al., 2019). This finding was seen
in the current study as participants reported
at the end of the day which condition they
received (caffeinated or decaffeinated
coffee) reported significant wanting of
caffeine rather than the actual coffee. These
results were in the opposite direction of the
original prediction of Hypothesis #1 (If
coffee consumption increases then caffeine
wanting will increase) these significant
findings shed light on the relationship
between caffeine amount and the wanting of
caffeine which can lead to caffeine addiction
in individuals. However, there are some
limitations to this study as the two studies
were testing different hypotheses. The
current study was conducted on a small
sample size of three participants which may
not generalize to the general population of
daily caffeine consumers. However, further
research should be conducted on different
ways individuals can quit caffeine
consumption easily.
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4.3 Implications of Results

References

Possible applications from the current
findings of caffeine craving, after not
consuming any or very little amounts of
caffeine can provide further research on
addiction. For example, individuals should
plan on slowly decreasing the amount of
caffeine consumed daily should they be
trying to quit rather than quitting cold
turkey. Implications can also be made
towards further education on caffeine
consumption, especially towards young
adults.
We originally conducted the current
study to determine what makes caffeine very
addictive and why it can be so hard to quit.
Based on our experimental results, we can
recommend that acute effects of day-to-day
variations in caffeine intake should overall
make it easier to quit. Results from this
study can raise new important questions on
caffeine consumption and the wanting of
caffeine.

Juliano, L. M., Kardel, P. G., Harrell, P. T.,
Muench, C., & Edwards, K. C. (2019).
Investigating the role of expectancy in
caffeine withdrawal using the balanced
placebo design. Human
Psychopharmacology: Clinical and
Experimental, 34(2), 1–12.
http://dx.doi.org.libsecure.camosun.bc.ca:
2048/10.1002/hup.2692
Koranyi, N., Brückner, E., Jäckel, A.,
Grigutsch, L. A., & Rothermund, K.
(2020). Dissociation between wanting
and liking for coffee in heavy drinkers.
Journal of Psychopharmacology, 34(12),
1350–1356. https://doiorg.libsecure.camosun.bc.ca:2443/10.117
7/0269881120922960
West, O., & Roderique-Davies, G. (2008).
Development and initial validation of a
caffeine craving questionnaire. Journal of
Psychopharmacology, 22(1), 80–91.
https://doiorg.libsecure.camosun.bc.ca:2443/10.117
7/0269881107082746

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Table 1
Correlations for Study Variables
Variables

Participant #1 Participant #2 Participant #3 Pooled raw
data

Pooled
standardized
data

r

n

r

n

r

n

r

n

r

n

Caffeine amount
0.18
& wanting
caffeine

7

0.96*

7

0.19*

7

0.64*

21

0.44*

21

0.18

7

0.97*

7

-0.79*

7

0.51* 21

0.13

21

0.85*

7

-0.91*

7

0.09

7

-0.02

0.01

21

Anticipated
pleasure of
having
caffeine &
wanting
caffeine
Withdrawal
symptoms &
wanting
caffeine

21

Notes. r = correlation coefficient, n = number of days sampled.
* p < .05.

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Table 2
Descriptive Statistics for Wanting Caffeine Across Different Caffeine Amount Conditions
Condition

Statistic

Participant
#1

Participant
#2

Participant
#3

Pooled
raw
data

Pooled
standardized
data

Caffeinated
Coffee

M

4.75

2.25*

4.33*

3.73*

-0.57*

SD

2.22

0.96

0.58

1.79

0.70

n

4

4

3

11

11

M

6.50

7.00

8.33

7.43

0.89

SD

0.71

1.41

0.58

1.13

0.39

n

2

2

3

7

7

Decaf
Coffee

Note. M, SD, and n, represent mean, standard deviation, and sample size, respectively. Craving
caffeine each day on a scale of 0-10 as DV unit of measurement.
* p < .05 for comparison of caffeinated coffee condition with its respective decaffeinated coffee
condition.

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Figure 1
Association Between Caffeine Amount and Wanting Caffeine Using Pooled Raw Data

Notes. Marker colour differentiates participants: red = participant #1, orange = participant #2,
and yellow = participant #3. Some data might not be visible in the figure due to overlapping
markers.

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Figure 2
Association Between Caffeine Amount and Wanting Caffeine Using Pooled Standardized Data

Notes. Marker colour differentiates participants: red = participant #1, orange = participant #2,
and yellow = participant #3. Some data might not be visible in the figure due to overlapping
markers.

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Figure 3
Association Between Anticipated Pleasure From Caffeine and Wanting Caffeine Using Pooled
Raw Data

Notes. Marker colour differentiates participants: red = participant #1, orange = participant #2,
and yellow = participant #3. Some data might not be visible in the figure due to overlapping
markers.

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Stevens, Wang, & Mawle - J Camosun Psyc Res. (2023). Vol. 5(1), pp. 56-77.

Figure 4
Association Between Anticipated Pleasure From Caffeine and Wanting Caffeine Using Pooled
Standardized Data

Notes. Marker colour differentiates participants: red = participant #1, orange = participant #2,
and yellow = participant #3. Some data might not be visible in the figure due to overlapping
markers.

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Figure 5
Association Between Withdrawal Symptoms and Wanting Caffeine Using Pooled Raw Data

Notes. Marker colour differentiates participants: red = participant #1, orange = participant #2,
and yellow = participant #3. Some data might not be visible in the figure due to overlapping
markers.

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Figure 6
Association Between Withdrawal Symptoms and Wanting Caffeine Using Pooled Standardized
Data

Notes. Marker colour differentiates participants: red = participant #1, orange = participant #2,
and yellow = participant #3. Some data might not be visible in the figure due to overlapping
markers.

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Figure 7
Average Wanting Caffeine Across Different Caffeine Amount Conditions Using Pooled Raw
Data

Notes. Wanting of caffeine scores are shown for caffeinated coffee and decaffeinated coffee
conditions using pooled raw data from all participants. Errors bars show ± 95% confidence
levels. Overlapping scatterplot shows data from each participant. Marker color differentiates
participants: red = participant #1, orange = participant #2, and yellow = participant #3.

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Figure 8
Average Wanting Caffeine Across Different Caffeine Amount Conditions Using Pooled
Standardized Data

Notes. Wanting of caffeine scores are shown for caffeinated coffee and decaffeinated coffee
conditions using pooled raw data from all participants. Errors bars show ± 95% confidence
levels. Overlapping scatterplot shows data from each participant. Marker colour differentiates
participants: red = participant #1, orange = participant #2, and yellow = participant #3.

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Stevens, Wang, & Mawle - J Camosun Psyc Res. (2023). Vol. 5(1), pp. 56-77.

Appendix A
Questionnaire Created to Measure The Hypotheses
1. How many cups of coffee were consumed by the end of each day (1 cup = 237mL)
2. How much did you crave caffeine each day? (10 being extreme craving, 0 being not at
all)
0
1
2
3
4
5
6
7
8
9
10
0

1

2

3

4

5

6

7

8

9

10

0

1

2

3

4

5

6

7

8

9

10

0

1

2

3

4

5

6

7

8

9

10

0

1

2

3

4

5

6

7

8

9

10

0
0

1
1

2
2

3
3

4
4

5
5

6
6

7
7

8
8

9
9

10
10

3. How much pleasure did you anticipate before drinking coffee each day? (10 being
extreme pleasure, 0 being none at all)
0
1
2
3
4
5
6
7
8
9
10
0

1

2

3

4

5

6

7

8

9

10

0

1

2

3

4

5

6

7

8

9

10

0

1

2

3

4

5

6

7

8

9

10

0

1

2

3

4

5

6

7

8

9

10

0

1

2

3

4

5

6

7

8

9

10

0

1

2

3

4

5

6

7

8

9

10

4. How extreme were your withdrawal symptoms before drinking coffee each day? (10
being extreme withdrawal symptoms, 0 being none at all)
0
1
2
3
4
5
6
7
8
9
10
0

1

2

3

4

5

6

7

8

9

10

0

1

2

3

4

5

6

7

8

9

10

0

1

2

3

4

5

6

7

8

9

10

0

1

2

3

4

5

6

7

8

9

10

0

1

2

3

4

5

6

7

8

9

10

0

1

2

3

4

5

6

7

8

9

10
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Stevens, Wang, & Mawle - J Camosun Psyc Res. (2023). Vol. 5(1), pp. 56-77.

Appendix B
Questionnaire Created to Measure Wanting of Caffeine

1. How much did you crave caffeine each day? (10 being extreme craving, 0 being not at
all)
0
1
2
3
4
5
6
7
8
9
10
0

1

2

3

4

5

6

7

8

9

10

0

1

2

3

4

5

6

7

8

9

10

0

1

2

3

4

5

6

7

8

9

10

0

1

2

3

4

5

6

7

8

9

10

0

1

2

3

4

5

6

7

8

9

10

77