In conjunction with the release of its 1996 and 1997 annual reports, the UN's International Narcotics Control Board issued warnings about the dramatically increasing use of methylphenidate, primarily in the United States.

Methylphenidate was classified under the 1971 Convention on Psychotropic Substances in Schedule II, as having 'high abuse potential'. Subsequently, its manufacture, consumption and abuse decreased considerably until the beginning of the 1990s.

However, the International Narcotics Control Board (INCB) has observed that world-wide use of methylphenidate has risen from less than 3 tonnes in 1990 to more than 8.5 tonnes in 1994, and continued to rise in 1995. The United States accounts for approximately 90 per cent of total world manufacture and consumption of the substance. The unprecedented sharp increase is due to its controversially extensive use in the treatment of 'attention deficit disorder (ADD)' in children. Some other countries have also reported more moderate increases in the use of methylphenidate for this purpose.

ADD is a term used to describe a syndrome largely manifested in behavioral patterns. The primary signs of ADD are inattention, impulsivity and, in some cases, hyperactivity. Patients are generally boys between the ages of 6 and 14. The combination of symptoms varies from patient to patient, and concerns have been raised that some doctors prescribing methylphenidate are opting for an 'easy' solution for behavioral problems which may have complex causes.

The INCB shares the concern of the United States Drug Enforcement Agency (DEA) about the increased use of methylphenidate, most commonly marketed in that country under the brand name Ritalin. The latest data indicates that 10 to 12 per cent of all boys between the ages 6 and 14 in the United States have been diagnosed as having ADD and are being treated with methylphenidate. Treatment is more prevalent in middle class communities and is expected to rise in 1996.

Among the dangers, as the Board sees it, are that ADD might be diagnosed too often overlooking other causes for attention and behavior problems and that doctors may be overprescribing methylphenidate. United States investigators found divergent prescribing practices among physicians, only 1 per cent of whom were responsible for the majority of all methylphenidate prescriptions issued. This also has impact on regional variations in the use of methylphenidate.

The Board is also concerned that, contrary to labeling, some doctors prescribe stimulants to children under the age of six and, in many cases, other recommended forms of treatment are not applied. The duration of treatment with methylphenidate, which in many countries is restricted to three years, tends to be much longer in the United States and many children remain on it into adolescence and even adulthood. No information on possible side-effects of such long-term treatment with methylphenidate is currently available.

Abuse of methylphenidate in the United States has increased, with serious damage to health, and a black market in the drug has recently emerged. The substance is abused mainly by adolescents who purchase tablets from children under treatment for ADD or steal them from school medical wards. A preferred method of abuse is to crush the tablets and snort the powder. Since the drug is touted as "accepted medication" for children, abusers are unaware of its health hazards, which include addiction and a range of stimulant-abuse symptoms.

The INCB is also concerned that the use of Ritalin is being actively promoted by an influential parent association, which has received significant financial contributions from the preparation's leading United States manufacturer. The same parent association has petitioned the DEA to ease the control of this substance, a move which would make methylphenidate even more easily available. Among the changes sought is dropping the requirement that the patient be re-examined by a doctor before a prescription for methylphenidate can be refilled.

At present, the unprecedented high level of ADD diagnosis in children, the very widespread prescription of Ritalin and the growing abuse and black market appear to be limited to the United States. But, the INCB foresees the likelihood that this trend will soon take hold in other countries. Some of the parent groups promoting methylphenidate in the United States have announced their intention to extend their activities outside the country. The Board is therefore requesting all Governments to exercise utmost vigilance to prevent the overdiagnosing of ADD and any medically-unjustified treatment with methylphenidate and other stimulants. It has also requested the World Health Organization (WHO) to investigate this matter and to provide expertise to national public health authorities.

With abuse of illegal amphetamine-type stimulants reaching epidemic proportions, the International Narcotics Control Board (INCB) is concerned that despite the warning it issued a year ago, the issue still requires serious attention.

Methylphenidate, a central nervous system stimulant with properties similar to those of the widely-abused amphetamines, has been increasingly used to treat attention deficit disorder (ADD) in children. Global licit consumption of the substance -- marketed mainly as 'Ritalin'-- rose from less than three metric tons in 1990 to more than 10 tonnes in 1995. About 90 per cent of global consumption is in the United States. Canada consumes per capita about one half the United States amount, and the quantities dispensed in Australia, Switzerland and other countries are also rising but from significantly lower levels.

Although proposals to weaken domestic control of methylphenidate were withdrawn in the United States following the alarm raised last year by the Board and others, consumption of the substance is still rising steeply to an estimated 10.5 tonnes in 1996 and a projected 13 tonnes in 1997. Reports indicate that in some schools in the United States a very high percentage of students receive stimulant medication, primarily methylphenidate. Particularly worrying is the fact that abuse of this substance is not restricted to adolescents and adults; the number of pre-adolescents abusing the drug is expanding. According to the United States Drug Abuse Warning Network (DAWN), the estimated number of methylphenidate-related emergency room cases for 10- to 14-year-olds has multiplied tenfold since 1990 and, in 1995, reached the level of cocaine-related emergencies for the same age-group.

In drawing attention to the methylphenidate problem in its Report of a year ago, the Board raised the issues of possible overdiagnosing of ADD, questionable promotional practices for methylphenidate, and the diversion of the substance from licit channels and an increase in its abuse. The therapeutic use of methylphenidate is now under scrutiny by the American medical community; the INCB welcomes this .

Methylphenidate, due to its high abuse potential, was one of the first substances to be placed under international control in Schedule II of the 1971 Convention on Psychotropic Substances.

The primary signs of ADD are inattention, impulsivity and, in some cases, hyperactivity. Those diagnosed are generally boys between the ages of 6 and 14. However, concerns have been raised that doctors are resorting to methylphenidate as an "easy" solution for behavioural problems which may have complex causes. Critics warn that parents' and teachers' assessments of what constitutes "inattention" and "impulsivity" are highly subjective and that doctors' prescribing practices for methylphenidate are far from uniform. A black market in the drug has emerged in recent years, with adolescents and even adults buying tablets from children under treatment or tablets stolen from school medical wards, in addition to the diversion of methylphenidate from pharmacies by theft or forged prescriptions. The preferred method of abuse is to crush the tablets and snort the powder. Since the drug is touted as "accepted medication" for children, abusers are unaware of its health hazards, which include addiction and a range of stimulant-abuse symptoms.

In its current report, the Board reiterates its request to all Governments to exercise the utmost care to prevent overdiagnosing of ADD in children and medically unjustified treatment.