ATLANTA , Georgia ( CNN ) -- Susan Todd loves her daily coffee fix . `` I can drink four or five cups , easily , comfortably , '' said Todd , 59 , of Clinton Township , Michigan . Skeet Spillane ( right ) got severe headaches when he quit caffeine . His wife said he was cranky most of the time . But if she skips her regular dose of caffeine , Todd warned , watch out . `` I feel lousy all over . It 's not that anything hurts , '' she explained . `` I just feel sluggish , and a cup of caffeine will cure that . '' Todd is among the estimated 80 to 90 percent of North American adults and children who consume caffeine products every day . Experts estimate about half that number will experience headaches and other symptoms from caffeine withdrawal syndrome . There are a number of reasons why someone might need to reduce or stop their daily caffeine intake . Experts tell pregnant women not to consume more than 200 milligrams of caffeine a day ( about one 12-ounce cup of coffee ) . Caffeinated products are not recommended for people who are prone to panic attacks or those who suffer from anxiety . Some surgical patients may also experience the symptoms of caffeine withdrawal syndrome on the day of surgery , because they are told not to eat or drink anything . Researchers at Johns Hopkins University in Baltimore , Maryland , recognized the condition as a disorder five years ago after reviewing decades of studies . They concluded the higher the caffeine intake , the more likely a patient was to suffer from severe withdrawal symptoms when denied the ingredient . Watch more on caffeine withdrawal syndrome » . Researchers also reported that some caffeine users considered themselves addicted to caffeine because they were unable to quit or cut down on their usage . Michael Kuhar , chief of the division of neuroscience at the Yerkes National Primate Research Center at Emory University in Atlanta , Georgia , prefers to use the word `` dependent '' rather than `` addicted . '' Even though he called caffeine a drug , Kuhar would n't go so far as saying it has reached the status of cocaine or heroin . According to Kuhar , caffeine is a mild stimulant . `` If you take a cup of caffeine you 're likely to feel good and energized , '' he said . Miss that cup of `` Joe '' or can of cola and do n't be surprised if you start feeling funny , Kuhar warned . He said some people complain of `` headache , fatigue , sleepiness , inability to focus and concentrate . '' Others report experiencing flu- like symptoms , irritability , depression and anxiety after skipping as little as one cup of coffee a day . Kuhar explained that caffeine blocks receptors in the brain that can dilate blood vessels causing headaches . `` Withdrawal symptoms can start from 12 to 20 hours after your last cup of coffee and peak about two days later and can last about as long as a week , '' Kuhar added . It is not just coffee that can lead to caffeine withdrawal . While a 6-ounce cup of brewed coffee contains about 100 milligrams of caffeine , tea and cola have about 40 milligrams each , a bar of milk chocolate has about 10 milligrams and hot chocolate has about 7 milligrams . Kuhar said that means adults as well as children may be suffering daily physiological and personality effects of caffeine withdrawal . He recommended that people who are motivated to give up caffeine , or cut back on consumption , do so very carefully . `` The thing to do is what we do with so many drugs -- basically you wean yourself off slowly , '' Kuhar suggested . `` That does n't mean it is going to be easy at every step , but it should be easier than going cold turkey . '' Johns Hopkins researchers also endorsed a stepped approach to quitting caffeine . They instruct patients to gradually substitute decaffeinated products or noncaffeinated products over time in order to reduce the likelihood of experiencing withdrawal symptoms . Kuhar suggested the process also can begin with reducing caffeine consumption by a half to a whole cup a day . Technology consultant Skeet Spillane , 42 , of St. Petersburg , Florida , started a step-down program after years of consuming up to three cups of coffee each day . He felt he was `` drinking way too much caffeine . '' Spillane said he knew right away that he was suffering from caffeine withdrawal when he started getting severe headaches . His wife told him he was cranky most of the time . He now drinks tea instead , and occasionally sneaks a cup of coffee . Looking back , Spillane admitted going through withdrawal was `` tough for a while , '' but he 's feeling better these days and he 's glad he 's not so dependent on caffeine .
Up to 90 percent of North Americans consume caffeine products every day . About half will experience withdrawal syndrome if they do n't partake . Symptoms include headache , fatigue , sleepiness , inability to focus . The higher the caffeine intake , the more likely a patient will suffer .