Editor's note: This popular story from the Daily Briefing's archives was republished on March 26, 2019.
Caffeine is the most-used drug in the world, and misusing it can have real, lasting side effects, but until you stop drinking coffee, it can be hard to determine if you have an addiction, Heidi Mitchell writes for the Wall Street Journal.
How caffeine works
When caffeine is ingested, Mitchell writes, it interferes with the brain's adenosine receptors, which ordinarily tell the body when it's feeling tired. Without signals from those receptors, you're left feeling awake and alert.
But on the other side, because your body has adjusted to the changes in adenosine, you'll typically feel tired or have a headache when the caffeine wears off. You may even feel nauseated.
Caffeine also stimulates the reward center of the brain, which, according to Laura Juliano, a psychology professor at American University, makes you brain say, "This feels good. How can I do this again?"
All of this parallels the ways that other recreational drugs affect your body. Juliana said, "Regular users will choose to take caffeine over money, over a placebo—so it shares the same reinforcing qualities that we see in other recreational drugs."
Over time, some people ultimately develop a condition known as caffeine use disorder. They become entirely dependent on caffeine and must ingest it to avoid withdrawal, Mitchell writes. They may have tried to quit but simply can't, and they may continue using caffeine even though it causes physical or psychological harms, such as difficulty sleeping.
How to know if you're addicted—and how to cut back
According to Juliano, most people with caffeine use disorder don't realize they're addicted until they have to stop drinking it for some reason. At that point, withdrawal symptoms clue them into the fact that they're dealing with an addiction.
"Since caffeine is embedded in our routines and social customs, people can go 20 years without missing a day, and they don't know they are dependent," she explained. "One of my patients was drinking 20 cups of coffee a day and experiencing a great deal of anxiety until he cut back."
According to Juliano, symptoms of withdrawal can include aches, headaches, or tiredness. But some people face even worse effects: "Sometimes people get caught off-guard, and they think they have the flu, or the worst headache of their life," she said. One patient even thought the withdrawal symptoms were caused by a brain aneurysm.
So what's a safe level of caffeine consumption? According to Juliano, up to 400 milligrams of caffeine each day should be fine for healthy adults—although some people experience physical dependence with only 100 milligrams of caffeine per day. A typical 12 oz. cup of coffee, Juliano said, can contain between 107 and 420 milligrams of caffeine.
If you're looking to cut back on your caffeine consumption, Juliano suggested weaning yourself off slowly rather than quitting cold turkey, as withdrawal symptoms will be far more intense if you quit immediately. Juliano recommended that "you cut your caffeine consumption in half each week."
Juliano also recommended checking in with yourself to gauge your overall health, how well you're sleeping, and how anxious you are—and consider whether caffeine could be having harmful effects in any of these areas.
"In our society, we have many people who suffer from anxiety and sleep problems, and they should consider giving themselves some relief from caffeine and seeing if that helps," she said (Mitchell, Wall Street Journal, 10/30).
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