The Pharmaceutical Journal
Vol 276 No 7391 p298
11 March 2006

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Does melatonin really help to combat sleeplessness? more
Space traffic facing threat from orbiting junk more
Discouraging suicides among the mentally ill more

Does melatonin really help to combat sleeplessness?

An editorial in the BMJ of 18 February discusses the most recent arguments over melatonin and how it might assist the sleepless.

In North America, it appears, melatonin is enjoying massive publicity as a drug classified as a nutritional supplement and taken by millions of people who believe that it will improve their ability to sleep. It is advertised and sold widely in pharmacies, drug stores, health food stores and on the internet. The BMJ claims that adequate controls of the drug’s pharmaceutical quality and safety have not been assured.

A review of the efficacy and safety of exogenous melatonin by experts at the University of Alberta appears in the same journal issue. It concludes that there is no evidence that melatonin is indeed effective in treating secondary sleep disorders or those resulting from sleep restriction associated with travel jet lag and disordered shift work.

It is not true that melatonin derived from outside sources induces sleep through its pharmacological activity. It acts as a regulating switch that advances or retards the body’s circadian phases. Its activity depends upon the time of day when it is taken.

If consumed at or about the onset of darkness it takes the place of endogenous melatonin in shifting the body forward towards the phase of sleep. The doses taken are much greater than those naturally secreted.

If, on the other hand, melatonin is taken at the time of awakening from natural sleep, the nocturnal period of reduced alertness and performance may be prolonged, delaying adaptation of the circadian rhythm.

Although adverse effects of melatonin reported have included headaches, dizziness, nausea and drowsiness, they appear to be no more frequent than the effects of a control placebo. It is concluded that short-term use of melatonin is perfectly safe.

Possible interaction with warfarin and a suggestion that the drug might cause harm in children suffering from severe epilepsy remain to be investigated.

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Space traffic facing threat from orbiting junk

According to two space scientists working in Houston, Texas, writing in Science for 20 January, the risks of encountering debris in the course of a space flight have grown enormously over recent years.

It has been reported by the US Space Surveillance network that more than 9,000 man-made objects are currently orbiting the earth. Their combined mass exceeds 5,000,000kg and they include many fragments of projectiles. Between 1991 and the start of 2005 three accidental collisions with such objects have been documented. Fortunately, none of these created large and trackable clouds of debris.

Given the estimated future launches of satellites involving low earth orbits, the rate of production of new debris attributable to collisions exceeds the loss of debris through natural decay. Collision fragments will raise degradation rate through atmospheric drag and solar radiation pressure until 2055, but thereafter the total satellite population will increase, resulting in a yearly average of 10.8 catastrophic and 7.4 lesser collisions over the next two centuries. Some 60 per cent of catastrophes occur at altitudes between 900 and 1000km above the earth. Experiments with more massive rocket bodies and spacecraft with longer orbit decay times will multiply collisions.

The removal of existing large objects from orbit will be necessary to avoid future problems. The cost of conventional means to achieve this would be enormous, and research into improved technology calls for co-operation between governments and private enterprise. Meanwhile, space system operations in near-earth orbits will face increasing risks.

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Discouraging suicides among the mentally ill

A commentary published in the British Journal of Psychiatry in February offers a rather depressing outlook on the problem of what measures are available to discourage mentally disturbed individuals from committing suicide or attempting it. Suicide prevention is regarded as a health service priority.

Two of the most important determinants of an act of self-destruction are age and psychiatric diagnosis. In older persons, physical health problems and major depressive illness commonly lead to suicide attempts, whereas in young persons personal relationship problems and misuse of drugs are more common.

A study carried out as part of a national inquiry into suicide and homicide made use of information from nearly 5,000 suicidal deaths registered with psychiatrists between 1996 and 2000 taken from the records of people contacting mental health services during the year before death.

Deaths of young persons were often linked to schizophrenia, personality disorder, unemployment or substance misuse. Schizophrenia patients committing suicide were often inpatients who were violent. About a third of those with depression died within a year of the onset of the disease. Many suffering from drug misuse or personality disorder had a history of missing health appointments or avoiding contact with mental health services. In the younger age groups, there was a prevalence of difficulties with relationships or legal problems. Patients younger than 25 require comprehensive care packages.

Recognition of depression and the need for its treatment, particularly at times of personal bereavement and when there is also physical illness, could reduce suicide among older patients.

Suicide among psychiatric patients, a study has shown, might be reduced by improving ward design and, in particular, removing fixtures that might be used in hanging. Records have shown that between 1996 and 2000, there were 20,927 deaths by suicide and 5,099 of those concerned had been in contact with health services in the year before death. These included 754 who were currently inpatients and 1,100 who had recently been discharged from inpatient psychiatric care. Nearly a quarter of those in the first group died within seven days of admission, most by hanging on the ward. Suicide after discharge was most frequent during the first two weeks, half of them on the first day. At last contact with staff, most of these patients were considered to be at low risk, and a third of the deaths were thought to have been preventable.

Discharged psychiatric patients should be followed up within seven days if they present with severe mental illness or a recent history of self-harm. Patients who discharge themselves should be strenuously encouraged to continue engagement with their therapists.

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