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There are many examples of people claiming they need their morning cup of coffee in order to be able to function at their normal level:

NIC blog:

Like many early morning risers, I need my morning cup of coffee to get my brain going.

Read This Article if You Must Have Your Morning Cup of Coffee:

Many Americans simply cannot function without their morning cup of coffee; in fact it is estimated that 72% of all Americans have a morning cup of coffee to get going

Does Coffee Take Away Blood Flow to the Brain?

Coffee is a staple drink of the morning, particularly for people who are tired and need a boost of energy to get going.

Does a single cup of (non-decaf) coffee drank in the morning have a real physiological effect that would aid in waking up and increasing concentration? Or is the morning cup of coffee ritual perhaps something closer to a placebo like effect?

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    +1 To help establish notability, I heard there was one study that claimed that the benefit of the cup was in getting rid of withdrawal symptoms. – Andrew Grimm May 27 '12 at 6:29
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    Hold on, I’m doing the experiment right now … – Konrad Rudolph May 27 '12 at 9:53
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    Are you asking: "Does someone who drinks coffee get a problem when there is a morning without coffee" or are you asking "Do people who don't drink coffee get up better when they switch to drinking coffee? – Christian May 27 '12 at 15:31
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    @Christian I don't see how my question could be clearer. Your latter interpretation is more accurate and I don't see how you could think the former. – Sonny Ordell May 28 '12 at 20:50
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    I think that it's about the Placebo Effect. If you think that your day will be better after drinking a coffee, it will be... I don't trust coffee, so if I'm tired I can drink as much coffee as I want and I'm still sleepy. – user7358 May 30 '12 at 18:04
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Yes it does, and there is plenty of evidence to support this fact.

A ~240mL (8 oz) cup of coffee has ~150 mg caffeine (from WolframAlpha)

In a recent review of 41 studies, Ruxton (2008) finds consistent evidence that doses of coffee less than and equal to what might be found in a cup of coffee provide "improvements in physical endurance, cognitive function, particularly alertness and vigilance, mood and perception of fatigue." Here is the abstract (with bits about a secondary hypothesis related to hydration replaced by '...':

The reputed benefits of moderate caffeine consumption include improvements in physical endurance, cognitive function, particularly alertness and vigilance, mood and perception of fatigue... This paper is a review of double-blind, placebo-controlled trials published over the past 15 years to establish what range of caffeine consumption would maximise benefits and minimise risks for cognitive function, mood, physical performance and hydration. Of the 41 human studies meeting the inclusion criteria, the majority reported benefits associated with low to moderate caffeine intakes (37.5 to 450 mg per day)... It was concluded that the range of caffeine intake that appeared to maximise benefit and minimise risk is 38 to 400 mg per day, equating to 1 to 8 cups of tea per day, or 0.3 to 4 cups of brewed coffee per day. The limitations of the current evidence base are discussed.

Another systematic literature review by Glade (2010), in which most effects were observed at doses were in the 50-200mg range (referred to as moderate), concludes:

The consumption of moderate amounts of caffeine 1) increases energy availability, 2) increases daily energy expenditure, 3) decreases fatigue, 4) decreases the sense of effort associated with physical activity, 5) enhances physical performance, 6) enhances motor performance, 7) enhances cognitive performance, 8) increases alertness, wakefulness, and feelings of “energy,” 9) decreases mental fatigue, 10) quickens reactions, 11) increases the accuracy of reactions, 12) increases the ability to concentrate and focus attention, 13) enhances short-term memory, 14) increases the ability to solve problems requiring reasoning, 15) increases the ability to make correct decisions, 16) enhances cognitive functioning capabilities and neuromuscular coordination, and 17) in otherwise healthy non-pregnant adults is safe.

A summary of the studies on which the above conclusions are based can be found in table 2 of the Ruxton reference, the first page of this table is shown below:

table 2

  • I made the image link to the large version, thanks. – Sklivvz Jun 2 '12 at 11:51
  • David, could you expand your answer to include aspects of any placebo effect? This isn't touched on in your answer. The image in your answer seems to imply that some studies found there was a placebo effect (if I am reading it correctly). – Sonny Ordell Jun 2 '12 at 23:36
  • @sonny placebo is generally used as a control. All effects presented in the table are considered effects of caffeine, because they were observed when caffeine was given, but not when a placebo was given. – David LeBauer Jun 4 '12 at 2:05
  • @David, that isn't stated clearly in the table or your answer, which is why I would like you to address it in your answer. I'm also reluctant to accept your answer as correct if yo9u don't address it because any increase in alertness could be due to a placebo effect, as the studies cited in row1's answer. – Sonny Ordell Jun 4 '12 at 2:38
  • It is okay if you don't want to select my answer, but it is clear from the table since the column says "results for caffeine vs. placebo". This means what I said in the previous comment. I may address this if I have time later, but it is really beyond the scope of the question. – David LeBauer Jun 4 '12 at 2:40
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There are a few studies that suggest that drinking coffee is just a placebo effect or the reversal of caffeine withdrawl.

Journal of Neuropsychopharmacology

Frequent coffee drinkers develop a tolerance to both the anxiety-producing effects and the stimulatory effects of caffeine. While frequent consumers may feel alerted by coffee, evidence suggests that this is actually merely the reversal of the fatiguing effects of acute caffeine withdrawal. And given the increased propensity to anxiety and raised blood pressure induced by caffeine consumption, there is no net benefit to be gained.

University of East London

People who drank the decaf coffee thinking it was caffeinated coffee did just as well on the tests as the people who really did have the caffeine...Both caffeine and expectation of having consumed caffeine improved attention and psychomotor speed," researchers wrote in the study.

University of California

People who drink caffeine decline in their ability to do tasks at the same time that their opinion of that ability goes up. Performance down, opinion of that performance up.

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    I don't see how these studies are answer the question. In the first study in J. Neuropsychopharmocology - If coffee increases alertness by reversing symptoms of withdrawal then the answer to OP is yes, coffee makes a person feel alert. In the Univ. E. London study - if drinking decaf coffee makes a person feel more alert, again, the answer to the OP is yes, coffee makes a person feel alert. The third study addresses memory, not focus. – David LeBauer Jun 2 '12 at 5:07
  • Could you define placebo? – Abe Jun 2 '12 at 5:13
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    @David, 1) Isn't that the same as saying a heroin addict doesn't feel like vomiting after taking a hit, therefore heroin prevents nausea? So after drinking coffee they are actually just back to feeling normal again and don't have an actual gain compared to a non-coffee drinker. 2) My understanding is that they are saying the perception of drinking coffee makes them feel more alert, so yes it makes them feel more alert, as would drinking purple water if they thought it would help. 3) Fair enough, I would say that memory and focus are related. – row1 Jun 2 '12 at 5:35
  • @David I asked the question with caffeinated coffee in mind. I will edit the question to reflect that. – Sonny Ordell Jun 2 '12 at 6:34
  • 1) yes, that would be a good analogy, and thus heroin could be said to prevent nausea. A doctor might prescribe Methadone for the exact same effect. 2) yes, but the question did not ask about purple water. 3) probably related but definitely distinct. All interesting points that could make interesting questions (and be treated in appropriate detail) on this site, biology.se, or cogsci.se. Please provide links if you find or ask such a question. – David LeBauer Jun 2 '12 at 11:39

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