Contributing factors
Sleep and wakefulness are influenced by different neurotransmitter signals. These signals are controlled by the body's circadian rhythms, the regular changes in mental and physical characteristics that occur in the course of a day. Most circadian rhythms are regulated by the body's biological "clock," the suprachiasmatic nucleus (SCN), which is located in the portion of the brain known as the hypothalamus, just above the point where the optic nerves cross. Light that reaches the retina creates signals that travel along the optic nerve to the SCN. Signals from the SCN travel to many regions of the brain, including the pineal gland, which responds to light signals by switching off production of melatonin. In darkness, the pineal gland renews melatonin production, causing drowsiness. The SCN also regulates other functions associated with the sleep/wake cycle including body temperature, hormone secretion, urine production, and changes in blood pressure.¹ Anything that disrupts the circadian rhythms, such as travel across different time zones (jet lag) or night-shift work can result in insomnia. Mental illness, stress, diet, drugs, and other factors that influence neurotransmitter function can also cause insomnia.

Conventional treatment
For short-term insomnia, doctors may prescribe sleeping pills (depressants), which cause drowsiness and improve sleep latency (the time it takes to fall asleep). However, most sleeping pills stop working after several weeks of nightly use, and long-term use can actually interfere with good sleep. In addition, many sleeping pills can lead to dependence or have other negative side effects. Mild insomnia can often be prevented or cured by practicing good sleep habits. For more serious cases, researchers are experimenting with light therapy and other ways to alter circadian cycles.¹

Nutritional/lifestyle considerations
A number of lifestyle and dietary factors can influence sleep and insomnia. Because stress is a major contributor to insomnia, stress-reduction techniques can be helpful for many people. Going to bed and rising at routine times can help maintain normal circadian rhythms for consistent sleep patterns. Keeping the bedroom a comfortable temperature is also important because extreme temperatures can disrupt sleep and prevent people from falling asleep. Daily exercise often helps people sleep better, however, exercising shortly before bedtime may interfere with sleep. For maximum benefit, it is best to exercise 5 to 6 hours before going to bed.¹ Stimulants, such as cafffeine and nicotine, can contribute to insomnia and should be avoided. Although it may initially help people fall asleep, alcohol should also be avoided because it interferes with sleep quality and duration.

Dietary factors that influence neurotransmitter function can also play a role in sleep latency and quality. High carbohydrate, low protein diets can increase serum levels of the amino acid L-tryptophan,² which is the precursor of serotonin and melatonin, two neurotransmitters that regulate sleep and relaxation. Studies have shown that supplemental melatonin can improve sleep latency in some cases,^3-10 presumably by adjusting disrupted circadian rhythms. 5-HTP (5-hydroxytryptophan), a natural tryptophan metabolite and serotonin precursor, has recently gained popularity as a sleep-promoting supplement, however large-scale studies on its efficacy for treating insomnia are lacking. Many herbs, such as valerian, kava kava, chamomile, hops, skullcap, and passion flower, have traditionally been used for promoting sleep and relaxation, but few of these have been subjected to scientific trials. A few small trials have shown valerian root to be effective in treating insomnia,^11-13 and one trial found a valerian-hops preparation to be as effective as the prescription sedative benzodiazepine, but with fewer side-effects.¹⁴