Addiction Addictive Behaviors Caffeine Side Effects of Caffeine and Caffeinated Drinks By Elizabeth Hartney, BSc., MSc., MA, PhD Elizabeth Hartney, BSc, MSc, MA, PhD is a psychologist, professor, and Director of the Centre for Health Leadership and Research at Royal Roads University, Canada. Learn about our editorial process Elizabeth Hartney, BSc., MSc., MA, PhD Medically reviewed by Medically reviewed by John C. Umhau, MD, MPH, CPE on November 20, 2020 John C. Umhau, MD, MPH, CPE is board-certified in addiction medicine and preventative medicine. He is the medical director at Alcohol Recovery Medicine. For over 20 years Dr. Umhau was a senior clinical investigator at the National Institute on Alcohol Abuse and Alcoholism of the National Institutes of Health (NIH). Learn about our Review Board John C. Umhau, MD, MPH, CPE Updated on November 22, 2020 Print Alicia Llop / Getty Images Caffeine is so common in American society, you can easily forget that it is an addictive drug. Office workers are particularly prone to habitual coffee drinking, as it helps to keep you alert and ward off fatigue. Some people even think caffeine improves their memory, although the research evidence for this is mixed. Does Drinking Coffee Actually Improve Memory? Short-Term Side Effects of Caffeine There certainly are recognized side effects of caffeine. Side effects of caffeine intoxication are included in the Diagnostic and Statistical Manual of Mental Disorders (DSM 5), the gold standard for diagnosing mental health problems. Diuresis – another embarrassing side effect of too much caffeine, you can end up running to the bathroom and urinating more fluid than you consumed.Excitement – although excitement is often a positive experience, after too much caffeine, you can get overly excited about trivial events, which can be awkward in social situations.Flushed face – a red face at work might make you look embarrassed, and can be embarrassing.Gastrointestinal disturbance – there is a range of gastrointestinal disturbances that can be side effects of too much caffeine, including stomachache, gas, heartburn, constipation, diarrhea, nausea and vomiting. However, while stomachaches are quite common after a lot of coffee, vomiting is quite rare, and if you have this reaction, you should avoid caffeine completely until you have discussed this with your doctor.Headache – caffeine is one of the most common causes of headache. It can trigger a headache when taken in excess, and if you drastically cut it out, it can cause a caffeine withdrawal headache. Caffeine has also been found to help alleviate migraine pain in the right doses. Insomnia – this can manifest in many different ways, but overall, it adds up to having difficulty getting enough sleep.Muscle twitching – involuntary muscle twitches are an annoying side effect of caffeine for some people, but there are other causes, so try abstaining from caffeine if this is an ongoing problem for you, and see if the twitching subsides. If it does not, talk to your doctor about treatment for this common problem.Nervousness – this is a sense of mental uneasiness, a kind of restlessness of the mind, that often goes hand in hand with anxiety.Periods of inexhaustibility – although this side effect may seem desirable, we all need rest. If you are unable to tire enough to get adequate rest, you can run yourself down, and not give your body adequate time to repair itself. You may not feel exhausted, but your body will become worn out without regular breaks from activity.Psychomotor agitation – this is a kind of physical fretfulness that makes it difficult to calm your body.Rambling flow of thought and speech – this is a common side effect of stimulant drugs and is often more annoying to the listener than to the speaker. But be aware that getting over-stimulated on coffee and dominating conversations might undermine your popularity at work.Restlessness – this is basically difficulty relaxing and calming yourself down.Tachycardia or cardiac arrhythmia – these side effects are changes to the speed and regularity of your heartbeat and are certainly a cause for concern. Stop using caffeine and see your doctor if you think your heartbeat is abnormal, particularly if you feel it is excessively rapid or irregular. Effects of Caffeine on the Body Research has shown that many people are unaware of these side effects, and a good deal of the research into caffeine has lauded the positive short-term effects, such as increased attention and energy, without taking these health effects into account. Was this page helpful? Thanks for your feedback! Learn the best ways to manage stress and negativity in your life. Sign Up You're in! Thank you, {{form.email}}, for signing up. There was an error. Please try again. What are your concerns? Other Inaccurate Hard to Understand Submit Article Sources Verywell Mind uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy. Meredith SE, Juliano LM, Hughes JR, Griffiths RR. Caffeine Use Disorder: A Comprehensive Review and Research Agenda. J Caffeine Res. 2013;3(3):114-130. doi: 10.1089/jcr.2013.0016 Juliano LM, Evatt DP, Richards BD, Griffiths RR. Characterization of individuals seeking treatment for caffeine dependence. Psychology of Addictive Behaviors. 2012;26(4):948-954. doi:10.1037/a0027246 Lee MJ, Choi HA, Choi H, Chung C-S. Caffeine discontinuation improves acute migraine treatment: a prospective clinic-based study. J Headache Pain. 2016;17(1):71. doi:10.1186/s10194-016-0662-5 Cornelis MC. The impact of caffeine and coffee on human health. Nutrients. 2019;11(2) doi:10.3390/nu11020416 Additional Reading Farag, N., Whitsett, T., McKey, B., Wilson, M., Vincent, A., Everson-Rose, S., and Lovallo, W. "Caffeine and Blood Pressure Response: Sex, Age, and Hormonal Status," Journal of Women's Health 19:1171-1176. 2010. American Psychiatric Association. Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition, (DSM 5), American Psychiatric Association. 2013. Derbyshire, E. & Abdula, S. "Habitual Caffeine Intake in Women of Childbearing Age," J Hum Nutr Diet 21:159–164. 2008.