Did you now that approximately 75 to 80 percent of the total world population drinks caffeine regularly?  And that in the United States, about 90 percent consume caffeine in one form or another?
It may not be totally surprising given the benefits it brings, not to mention the amazing taste and aroma you may be looking for every morning. And it’s not totally a newsflash that a lot of people have formed a habit around coffee. In fact, studies say that over a quarter of those consuming caffeine fall under the Diagnostic and Statistical Manual of Mental Disorders (DSM-5) Substance Dependence list. 
If you’re one of the coffee lovers wondering whether they may be having too much coffee, here are 5 signs that tell you it may be time to take it easy:
As a stimulant, caffeine can affect your mood.
Based on a review conducted by A. Nehlig, having 75 mg of caffeine (a cup of joe) every 4 hours can lead to a “pattern of sustained improvement of mood over the day.” It can increase alertness and well-being, help concentration, improve mood and limit depression. 
But too much of this good thing can get you hooked!
According to Dana Hunnes, Ph.D., M.P.H., R.D., senior dietician at UCLA Medical Center and adjunct assistant professor at the Fielding School of Public Health, caffeine “stimulates the dopamine receptors in our brain, kind of like cocaine and other certain drugs, just not nearly to the same extent." 
Because it affects your mind this way, too much coffee may lead to dependence. Because the coffee euphoria feels good, you may find yourself reaching out for another cup.
And if the next time you’re feeling moody and grumpy, check yourself. Do you feel the need to get another caffeine fix? Do you feel like a cup can get you more emotionally stable and back in a great mood again? If you said yes and yes, then it’s your body telling you to chill and take it easy on your coffee.
Plus, if you often find yourself grumpy and just a plain zombie right after getting out of bed, then it may be another sign that you may have developed a tolerance for the positive mood-altering effects of coffee.
In the coffee junkie’s world, this is called caffeine tolerance.
Drinking too much coffee every day may lead to tolerance, prompting your system to get more than your usual fix to get the same benefits.
An article on Caffeine Informer talks about caffeine tolerance.  It says that a first-time coffee drinker (or someone who has been off caffeine for a long time) has zero-tolerance. And these people get the most bang for the cup – euphoria, alertness, good mood, and increased energy and motivation.
But having too much may increase the tolerance, and hence wean off caffeine’s benefits. If you notice that your usual cup or two don’t perk you up anymore, it may be a sign that you’ve developed a tolerance for caffeine.
Luckily, there’s a workaround for this – in the form of caffeine cycling.
If after a cup or two you feel jittery and anxious – instead of being perky and alert – then you may have gone overboard with coffee.
Loading up on caffeine may lead to high anxiety and even panic attacks, especially for those who have mental health disorders. If you’re starting to notice yourself being high-strung and on the edge often, then it may be time to wean off your caffeine intake.
Did you know that caffeine helps ease migraine headaches? In fact, it helps pain relievers and headache meds work more effectively.
Moments before migraine strikes, blood vessels start to enlarge. What makes caffeine an effective pain reliever is its vasoconstrictive properties that restrict blood flow, narrowing the blood vessels and eventually helping ease the pain.
But having too much caffeine can create the opposite result – it could lead to headaches. There are two reasons why:
Based on research done at the John Hopkins Medicine Behavioral Pharmacology Research Unit, approximately 50 percent of coffee drinkers suffer from withdrawal headaches after skipping their caffeine fix for a day. 
Aside from perking you up, caffeine can also help you concentrate and become more productive?
If, during mind-numbing, brain-wracking moments, you want to feel like Popeye going for a whole can of spinach, just reach out for the coffee-maker and you’re likely to feel the same.
In fact, caffeine can help you absorb information and remember it more efficiently! Here are 8 ways caffeine can affect your concentration and mental performance.
But too much caffeine may negate this. If you’re wondering how much is too much, the magic number is 400 mg. If you want to know more how many cups of coffee or cans of cola 400 mg represents, then check out this article: How much caffeine should you have in a day?
There are supplements that can give you that caffeine fix while ensuring that you benefit from well-oiled cognitive functions.
VALI Caffeine and L-Theanine Nootropic Stack helps with concentration, being more creative, and staying focused without the headaches, crashes, and anxiety that can come from caffeine alone.
Want to know more signs that you may be having a little too much coffee than you're supposed to? Watch this space for part 2 of this article!
In the meantime, here's a video to tell if you're "addicted" or not:
Unless you work outdoors or indoors in a job where you are physically active all day, it can be difficult for some people who have desk jobs to stay awake at work without caffeine.
Maybe the most important thing you can do to make sure you don’t nod off at work is to get a good night of sleep, at least 7 to 8 hours, at a regular time every night. Boredom can also cause you to nod off. Other than getting a good night’s sleep and having a fascinating job, there are things you can do to stay awake.
How do investment bankers stay awake on their 18-hour shifts?
Investment bankers work such long hours that many resort to chemical stimuli. There have been rumors of methamphetamine and cocaine use among investment bankers to burn the midnight oil. Other investment bankers take Ritalin or Adderall, which are given to children with ADHD but which are stimulants for adults. But the mainstay is probably coffee, energy drinks, and other concoctions containing caffeine.
Some law students spend 60 hours a week studying. Those who’ve been through law school advise prospective students to leave the Xbox at home so they’re not tempted with potentially ruinous distraction. How do law students get energy to study so much?
One thing many law school students do not do is party and socialize a lot. This has a doubly salutary effect because the time spent not partying is time they can spend studying. And then they are not out of sorts, hung over or over-tired the next day from partying.