The Buzz On Caffeine & Bipolar Disorder

By Peter Jaret







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Your cup of joe is brimming with health benefits—but can it aggravate mood swings?

By Peter Jaret

If it wasn’t for coffee,” late night talk show host David Letterman famously quipped, “I’d have no identifiable personality whatsoever.”

Plenty of devoted coffee drinkers can probably relate. Coffee is one of the most popular beverages in the world, prized as much for its rich aroma and roasted taste as for its caffeine buzz. Largely because of the popularity of coffee (and to a lesser extent tea and cola), caffeine

is the most commonly used psychoactive substance in existence, consumed by 80 percent of people around the world.

The new health drink?

It’s easy to understand why caffeinated beverages are beloved worldwide. Many studies have shown that caffeine can sharpen attention, boost physical stamina, and counteract sleepiness. Caffeine is recognized as a bona fide performance-enhancing drug among athletes.

But perhaps the biggest surprise is that coffee beans are teeming with antioxidants and may have important health benefits. In a study of more than 125,000 men and women, researchers at Harvard School of Public Health found that coffee drinking was linked to a significantly lower risk of type 2 diabetes. When researchers at the University of North Carolina at Chapel Hill ranked beverages in terms of their health benefits, coffee and tea took second place after water.

Even in someone without a mood disorder, too much caffeine can cause nervousness, agitation, rapid or irregular heartbeat, dizziness, and mood changes.

That’s all good news for java junkies. But what about those of us with bipolar disorder? Can the buzz that caffeine causes worsen mood swings?

It’s a question worth asking. Even in someone without a mood disorder, too much caffeine can cause nervousness, agitation, rapid or irregular heartbeat, dizziness, and mood changes. Among individuals who experience periodic panic attacks, scientists have learned that they can trigger an attack by giving volunteers large amounts of caffeine.

Could too much caffeine consumption also cause—or at least exacerbate—symptoms of other psychiatric disorders? To find out, Virginia Commonwealth University psychiatrist Kenneth Kendler, MD, and his colleagues recently analyzed data drawn from interviews with more than 3,600 adult twins. “What we found first was that people who consumed the most caffeine were also a bit more likely to suffer from a range of psychiatric or substance abuse disorders,” said Kendler. “So there’s definitely an association.” But an association doesn’t mean one causes the other, he was quick to point out.

In fact, when the team looked more closely at identical twins, they found strong evidence that caffeine consumption doesn’t cause or worsen psychiatric symptoms. “Even where one twin consumed a lot of caffeine and the other consumed almost none, the risk of psychiatric disorders was about the same,”

Kendler said. He theorizes that the same genes that predispose people to a range of psychiatric disorders may also predispose them to higher levels of caffeine consumption. Kendler’s study did not look specifically at bipolar disorder. In fact, virtually no studies have researched caffeine use and bp symptoms. “You could certainly speculate that caffeine’s physiological effects could have an impact on symptoms of mania and depression,” said Kendler, “but it would be pure speculation. And there’s too much of that already.”

Common caffeine myths

Indeed, much popular wisdom about caffeine is wrong, according to psychologist Andrew Smith, PhD, a researcher at Cardiff University in the United Kingdom and one of the world’s leading experts on the substance.

If you drink too much coffee in the morning to stay alert, will you experience a slump in the afternoon? “We don’t find much evidence for that kind of rebound effect,” said Smith. Do habitual coffee drinkers need more and more coffee to get the same buzz? “Again, the answer seems to be largely no. In fact, most people are remarkably consistent in their caffeine intake. They may drink a couple of cups of coffee in the morning and then stop by noon, for example. People are very good at controlling the dose of caffeine that they get.”

Still, a small percentage of people are unusually sensitive to the effects of caffeine. They may feel anxious and agitated after drinking even relatively small amounts of coffee. Some habitual coffee drinkers who go cold turkey may experience withdrawal, specifically in the form of pounding headaches. “But that’s much less common than is widely believed and probably only affects about 10 percent of habitual coffee drinkers,” Smith said.

A cup of common sense

Where does all this leave the individual java lover?

If you drink a few cups of coffee during the day and don’t have any complaints about jitteriness or anxiety, chances are you don’t need to worry. If you drink a lot of coffee or other caffeinated beverages and tend to feel hyper or agitated, it’s worth reducing your consumption to see if caffeine is the culprit.

Cutting back may also be wise if you consume more than a couple of cups and have trouble sleeping. Caffeine, especially when it’s consumed later in the day, can disrupt sleep patterns, said Thomas Roth, MD, director of the Sleep Disorders Center at Henry Ford Hospital in Detroit, Michigan. “Our studies show that the less sleep people get, the more cups of coffee they drink. But using a powerful stimulant like caffeine isn’t a substitute for healthy sleep.”

Caffeine has a relatively short half-life of about eight hours, so it won’t take long to gauge the effect of consuming less. To avoid getting a headache, scale back gradually by drinking a little less coffee each day or gradually mixing more decaf in with the high-octane brew. Since decaffeinated coffee is just about as rich in antioxidants as caffeinated coffee, you’re likely to get many of the same potential health benefits, but without the buzz.

Printed as “The Buzz on Caffeine“, Summer 2008