Caffeine
Caffeine is probably the most widely used mood-altering substance. It is found in coffee, tea, cola, cocoa, and over-the- counter analgesics and stimulants. It’s not associated with any kind of social or serious health problem and is therefore not considered dangerous enough to regulate. It does, however, have some troublesome effects that are worth knowing about.

The term “caffeinism” refers to a group of symptoms caused by excessive, chronic ingestion of the substance, including restlessness, nervousness, and muscle twitching, as well as some gastrointestinal problems. It’s a common cause of insomnia or restless sleep. For people with depression or anxiety disorders, caffeine can aggravate symptoms and complicate treatment.

Withdrawal symptoms begin to emerge and peak within a day or two after the last ingestion of caffeine. These symptoms can include fatigue, headache, irritability, withdrawal, and poor concentration. It’s not uncommon for people who drink coffee all day long during the work week to experience caffeine withdrawal on the weekends or during vacations. The easiest way to diagnose caffeine withdrawal is to have the sufferer drink a cup of coffee or a Coke and see what happens.

Weekend headache sufferers who get relief from over-the- counter preparations that contain caffeine are unwittingly treating the withdrawal.

Nicotine
Addiction to nicotine is probably the most prevalent drug problem in today’s world. Nicotine is found in tobacco products such as cigarettes, cigars, pipe tobacco, chewing tobacco, and snuff. The addictiveness of nicotine is well documented, as are the health hazards of smoking and chewing tobacco.

Nicotine acts as a stimulant in a fashion similar to that of cocaine and amphetamines; however, its overall effect is less
pronounced. It also interacts with a number of other systems in the brain such as the cholinergic system and hormonal systems. It has reinforcing properties caused by its interaction with dopamine-producing cells in the pleasure center of the brain.

Smokers have been shown to unconsciously regulate their doses of nicotine to amazingly consistent levels. Even smokers who switch to “light” cigarettes eventually increase the number of cigarettes smoked or the depth of inhalation to keep the nicotine levels constant.

Nicotine’s effects are immediate and short-lived. Smokers generally begin to crave another cigarette within a few hours of the last one, and it is thought that the primary mechanism for addiction to cigarettes is that of treating the symptoms of withdrawal. In other words, the immediate reduction of anxiety and irritability that comes from smoking another cigarette tends to reinforce the addiction.

Although nicotine addiction does not cause the profound social and behavioral problems that result from the use of drugs like cocaine and amphetamines, it is associated with many serious medical problems, including cancer and heart disease. Quitting smoking is no easy matter, and there are high failure rates for all methods. Nonetheless, social pressure has encouraged many people to be successful in their efforts. It may be that as smoking becomes more and more socially unacceptable, the remaining smokers will be people with more complicated problems. For example, smoking is more prevalent among people who are addicted to other substances and among those with other psychiatric problems.

The reasons for this are not completely clear, but it’s probably because the brain is so complicated and nicotine’s effects are fairly widespread throughout the nervous system. Changing the system by eliminating nicotine may cause a cascade of effects in people whose brains are otherwise abnormal, which would make quitting much more complicated.