Jetlag presents itself if multiple time zones are passed through in a short amount of time and the natural inner clock is no longer in line with the actual time of day. This causes the hormone balance that underlies a normal and typical daily rhythm to become confused. Jetlag is more severe the more time zones are crossed, as adapting the inner rhythms can only occur slowly. Typical symptoms include nightly sleeplessness and drowsiness during the day, general discomfort, and other somatic symptoms such as difficulties concentrating and cardiovascular problems. There are possible impact on health: daytime drowsiness, problems falling and staying asleep at night, limited physical fitness, reduced cognitive ability, mood swings and gastrointestinal and psychosomatic problems. Reaction time can also be impaired. In the worst cases, cardiovascular illnesses, diabetes and cancer can occur.

In this case, melatonin is effective in regulating the shift of the sleep-wake rhythm as they occur, especially with flight across multiple time zones. Multiple studies have proven that melatonin can speed up the adjustment to the new time zone. Melatonin has also proven itself useful in alleviating other jetlag symptoms. Melatonin is also well suited for shift workers who often suffer from sleep disturbances, as these people—similar to those with jetlag syndrome—are exposed to frequent changes in the day’s rhythm. It is important that the exact timing of intake is regarded in order to allow the shift in phases caused by melatonin to be effective. An example of such an ideal time would be, for example, between 9 p.m. and 10 p.m. of the new time zone with jetlag, and one hour prior to the new rest phase for shift workers. This type of chronotherapy can be supported through light therapy, which applies strong light for a short amount of time directly to the eyes. With jetlag this occurs in the morning of the new time zone, and immediately preceding the active phase among shift workers.

Pharmacologically Induced Sleep Disorders

Many drugs and/or stimulants can also negatively influence the release of melatonin. It has been demonstrated that certain sleep aids such as benzodiazepine, as well as heart preparations such as beta blockers, suppress the production of melatonin. Excessive alcohol and/or caffeine consumption from coffee or black tea can also have a negative impact on the release of melatonin and lead to sleep disruption or unhealthy sleep. In the attempt to support endogenous production of melatonin through taking preliminary substances such as tryptophan and/or 5HTP, it is important to remember that elderly people are no longer capable of synthesizing melatonin out of the above substances. The result of an evening administration of these products is then a heightened level of serotonin, which leads to being awake rather than heightened melatonin levels, with the end result of a pharmacologically induced sleep disruption.

With endogenous sleep disturbances the amount of the produced melatonin is either reduced, or the melatonin is released at the wrong time, even though one is in a normal day/night rhythm.

Delayed Sleep Onset Syndrome

With the delayed sleep onset syndrome a sleep disturbance is present which is caused through a shifted melatonin rhythm. It normally appears among teenagers and young adults which belong to the chronotype “night owls.“ They make night into day, and stay up until the early morning hours, and then sleep into the afternoon. Those affected report chronic sleeplessness.

The delayed sleep onset syndrome of these owls is most easily treated with the help of light therapy in the morning. It is recommended to conduct the light therapy early in the morning in order to shift the sleep-wake rhythm forward. Similar effects can be achieved through taking melatonin in the first evening hours, whether it be fast-releasing or pulsing melatonin. A combination of both therapies is also possible.

 Sleep-Wake Disruption among the Blind (Non-24 Syndrome)

Non-24 is a serious, severe, and chronic disturbance of the day/night rhythm that is especially common among the blind. People with non-24 syndrome are not able to adjust or synchronize their inner clock to the 24-hour rhythm of a day. These people live in their own rhythm that lasts between 24-and-a-half and 25 hours. This leads to the fact that each day they fall asleep and get up 30 -60 minutes later. All the other rhythms of the body, such as body temperature, hormone release, or the height of activity, also shift accordingly.

The goal of a chronobiologically correct therapy is to synchronize the inner clock of the affected people with the 24-hour rhythm of the day. If necessary, this can be done in the mornings through light therapy, as well as through substances that suppress daytime drowsiness. However, this only works for those who are still able to minimally perceive light and dark. For all other patients the nighttime administration of melatonin or similarly acting substances should encourage sleep and serve as a time-keeper for the inner clock to follow.

Different substances can be used to adapt the endogenous rhythm of the blind to that of a normal day/night rhythm: On the one hand, melatonin can be used as a time-giving hormone in the evening. Through the ingestion of melatonin, whether it be a fast-releasing or a pulsing formula, the body is signaled that it is now night. Recently some melatonin-like substances have also become available, such as Tasimelteon (Hetlioz®), which also needs to be taken in the evening and works over the melatonin receptors in the brain to set the inner clock according to the day/night rhythm.

Sleep Disturbances in Old Age and Special Life Situations

Even though a life-prolonging effect has not yet been proven among humans, it is certain the melatonin does positively impact the quality of life, especially among the elderly. The hormone appears to be effective in the treatment of diverse processes which are associated with aging, such as disturbances in the sleep-wake rhythm, lowering of blood pressure and in the correction of immune system deficiencies. It is also assumed that the hormone is helpful in delaying the molecular destruction, cell loss and deterioration of the organism, which are all factors that contribute to ageing.

Due to an age-related decrease of the nightly melatonin level, elderly people often suffer from sleep disturbances. It is currently assumed that every second person over the age of 65 is affected by sleep disturbances. In this instance, the treatment with melatonin has proven itself to be helpful. Studies demonstrated that the use of melatonin not only ensured improved quality of sleep, but also decreased depression and fears. The positive effect of this hormone can be ascribed to its ability to normalize the circadian rhythm. Such a regenerated rhythm can then effect all other physiological processes positively, and can significantly increase the quality of life and possibly be a factor in increasing life expectancy.

A special group of patients are women going through menopause. This stage of life is accompanied by deep-seated hormonal changes that not only lead to sleep problems, but can also evoke other symptoms. The extent to which melatonin secretion changes through this event is still the subject of different investigations. Nevertheless, studies with women in perimenopause have been able to demonstrate that pituitary gland activity, as well as function of the thyroid, can be improved with the ingestion of melatonin. Additionally, most women treated with melatonin reported a general improvement in mood and a significant alleviation of depression. This thesis is supported through the fact that high melatonin concentration in old age—as demonstrated in all previous studies—improves general wellbeing and can lead to alleviation of age associated illnesses. This effect mirrors the effect of melatonin as a sleep regulator, as well as that of a potent antioxidant. For all humans, including menopausal women, it could be demonstrated that restful sleep significantly improved general wellbeing on the following day.

Sleep Disturbances with Winter Depression

So-called winter depression, also known as seasonal affective disorder (SAD), deals with a special form of depression that is most prevalent in the fall and winter months. The primary symptoms are a suppressed mood, reduction of energy levels and fearfulness, as well as prolonging of sleep time, increased appetite for sweets (ravenous appetite for carbohydrates), and weight gain. On the other hand, depression that is not seasonally characterized is rather accompanied by loss of appetite, weight loss and shortening of sleep. As this type of depression is more frequently found in regions that have long winters with long nights (for example the polar regions), it is assumed that this people suffer from a disruption in melatonin production. Often these people release melatonin more frequently and for longer periods of time.

Interestingly, a positive effect of exogenous melatonin could still be demonstrated. A small, early evening dose of melatonin in a fast-releasing dosage form can already help to improve the synchronization of the inner clock and the biological day rhythm with the light conditions present during the winter, which significantly improves the emotional state. Additionally, light therapy has also proven itself as a treatment option. When applied in the morning it not only reduces morning melatonin levels, but also impacts the entire rhythm positively.