Caffeine Confusion

There are three recent articles about caffeine that are being discussed in the news.

The topics:
Does caffeine cause hallucinations? (Only in susceptible people.)
Does coffee prevent dementia? (Maybe.)
Does caffeine interfere with verbal and motor learning? (Only if it prevents proper sleep necessary for memory consolidation after learning a task, by keeping brain acetycholine levels artificially elevated.)

The bottom line: if you are drinking moderate amounts of coffee (less than five cups per day), don't drink them too late into the day, and are experiencing no side effects (such as anxiety, palpitations, racing heart, or unexplained elevated blood sugars as a stressed person with diabetes), then don't worry! Worry more about what you PUT in the coffee - go easy on the fat and sugar.

Does Caffeine Cause Hallucinations?
http://news.yahoo.com/s/livescience/20090114/sc_livescience/caffeinecancausehallucinations
In short, no. In people who are already susceptible to hallucinations, however (about 3% of the population), caffeine may increase hallucinations. Researchers postulate that since caffeine increases cortisol release in people already under stress, that somehow the combination of caffeine, stress, and cortisol, leads to the findings.
It is important to note that caffeine on top of stress causes increased cortisol release. This could explain why some patients with diabetes note increased blood sugars after caffeine consumption. As noted below, however, some studies show DECREASED risk of type II diabetes with daily coffee consumption.

Can Coffee Ward Off Dementia?
http://www.webmd.com/alzheimers/news/20090116/coffee-strong-enough-to-ward-off-dementia
From the article:
“Drinking coffee in moderate amounts during middle age may reduce the risk of dementia and Alzheimer's disease in the elderly, according to a new study.
Researchers in Finland and Sweden examined the records of 1,409 people whose coffee drinking habits had been recorded when they were at midlife.
Those who drank three to five cups of coffee per day in midlife were much less likely to have developed dementia or Alzheimer's in follow-up checks two decades or more later, the researchers say in the January issue of the Journal of Alzheimer's Disease…

…In the study, participants were asked in 1972, 1977, 1982, or 1987, when they were all in midlife (average age 50), how much coffee they drank. Then they were split into three groups: low coffee drinkers (zero to two cups per day), moderate coffee drinkers (three to five cups per day), and high coffee drinkers (more than five cups per day).
After an average of 21 years, 1,409 people between ages 65 and 79 were re-examined. A total of 61 were classified as having dementia, 48 with Alzheimer's…
The study showed that coffee drinkers at midlife had a lower risk for dementia or Alzheimer's later in life than people who drank little or no coffee at midlife. The lowest risk was found among moderate coffee drinkers. Moderate coffee drinkers had a 65%-70% decreased risk of dementia and a 62%-64% decreased risk of Alzheimer's compared with low coffee drinkers, the researchers write…
The researchers note that previous studies have shown that coffee drinking improves cognitive performance, and caffeine reportedly reduces the risk of Parkinson's disease.
The researchers say it's not known how coffee would offer protection against dementia, but that coffee drinking also has been associated with a decreased risk of type 2 diabetes, which is a risk factor for dementia.
The authors speculate that the effect may have something to do with coffee's antioxidant capacity in the blood.
The study also showed that tea drinking was not associated with a reduced risk of dementia or Alzheimer's disease.”


Caffeine No Substitute for a Nap to Enhance Memory
Equivalent of 2-3 Cups of Coffee Worsens Motor Learning and Word Recall
http://www.nimh.nih.gov/science-news/2008/caffeine-no-substitute-for-a-nap-to-enhance-memory.shtml

Bottom line: after learning something new, take a nap! It helps your brain “consolidate” the new memories, so you keep them for the long term. If you have caffeine, it may impair the “memory making” process.

From the article:
“Ninety percent of Americans use caffeine daily, some substituting it for sleep. While the stimulant enhances alertness and concentration, it's been unclear whether it also helps learning and memory. By contrast, daytime naps, like nighttime sleep, benefit both alertness and memory…
Evidence suggests that caffeine interferes with tasks that require processing explicit, as opposed to implicit, information - like recalling a specific word, versus remembering how to type or ride a bike. Studies show that consolidation of such explicit verbal memory during sleep depends on lowered levels of the chemical messenger acetylcholine in the brain's memory hub. Yet, by blocking activity of a natural sedative chemical, caffeine boosts acetylcholine in this hub.
"This increase in acetylcholine by caffeine may impair the consolidation process by blocking replay of new memories," proposes Mednick.”
No caffeine before bed or naps, if you want to learn most effectively.