Objects are the same size, obviously, whether they are near or far, but our minds perceive size relative to surroundings. The dogs appear much larger the closer they get. They may seem huge to a person who is afraid of dogs. 3) Depressants, Stimulants, and Hallucinogens

Depressants numb one's feelings. They act as anesthetic to one's nervous system. One loses energy, almost as if very fatigued. A person under the influence of a depressant will feel very apathetic towards everything. It is all too much effort. Alcohol acts as a depressant, with real physiological effects in addition to the psychological effects. Heavy alcohol consumption decreases metabolization of fat in the liver and also suppresses movement of white blood cells, making one more prone to infections. Heavy alcohol consumption causes the stomach to produce more digestive acids, which can lead to ulcers or acid reflux disease.

Nicotine is a stimulant. Nicotine can stimulate nerve cells, making one feel more alert. When one inhales a cigarette, the nicotine travels quickly to the brain cells, altering mood and performance. One's heart rate and breathing rate increase. A person who smokes can feel more energized with a cigarette and feel a heightened sense of awareness.

Marijuana is a hallucinogen, although hallucinations rarely occur unless great amounts of marijuana are used. Marijuana heightens the senses, increasing one's perceptions with respect to sight, smell, hearing and taste. An individual experiences a heightened sense of consciousness but a greatly reduced sense of motivation. The appetite may also increase. The heart beat can increase with marijuana use, making the user feel more alive. Used long-term, however, marijuana can adversely affect memory.

4) Sleep Cycle and Sleep Disorders

There are five stages in the sleep cycle: one through four and the rapid eye movement (REM) cycle. In stage one, sleep is light. One can move easily from sleep to wakefulness. The eyes move slowly and muscle movement slows. In stage two, eye movement stops....

In stage three, very slow brain waves (delta waves) are interspersed with smaller, faster waves. In stage four, almost all the waves are delta waves. Stages three and four are deep sleep, sometimes called delta sleep. There is no eye movement or muscle activity, and it is very difficult to wake someone during delta sleep. During REM, there is rapid eye movement, increased heart beat, more rapid breathing, and increased brain waves. During this stage, dreams occur; people who wake during this phase will remember their dreams.
Insomnia is a sleep disorder that can occur in one, or both, of two ways. People can have difficulty falling asleep initially, or they can fall asleep but have difficulty staying asleep. Doctors sometimes prescribe medication for insomnia, but some treatments can be habit-forming. Behavioral strategies may be a better option for many sufferers. These include limiting activities in the bedroom (e.g., removing the television), avoiding caffeine and alcohol, and relaxation techniques.

Another sleep disorder is sleep apnea. This is a physical problem in which the person breathes irregularly, with shallow breaths, or even stops breathing entirely for a few seconds. It is usually caused when the soft tissue in the back of the throat softens too much and blocks the airway. Sleep apnea can occur in anyone at any age, but is more common in men and in people of both genders who are overweight.

A third sleep disorder is one known as "restless leg syndrome." Sufferers feel a tingling or crawling sensation in their legs and they feel unable to keep their legs still. The sensation can also occur in the arms, although this is much less common. Movement can provide temporary relief to the crawling sensation, but it can resume once the person stops movement. Although medication has been shown to be effective in treating restless leg syndrome, many of the symptoms can be just as effectively treated as insomnia: avoidance of alcohol and caffeine, and relaxation techniques. Daily exercises and regular massages can also be beneficial.