Changes in use of psychostimulant medication for ADHD in South Australia (1990-2006)

Poisonings with ADHD medication in children under the age of 5 years in Australia: a retrospective study, 2004-2019

OBJECTIVE

To describe the temporal relationships in attention-deficit hyperactivity disorder (ADHD) medication poisoning exposures in children; describe patient demographics, medications involved, poisoning exposure reasons and disposition.

DESIGN

A population-based, retrospective cohort study of calls to Australia's largest Poisons Information Centre. Poisoning exposure counts and dispensing-adjusted rates were modelled with Poisson, quasi-Poisson and negative binomial regression where appropriate.

SETTING

Calls to the New South Wales Poisons Information Centre and dispensings on the Pharmaceutical Benefits Scheme.

PATIENTS

Children under the age of 5 years.

RESULTS

There were 1175 poisoning exposures to ADHD psychostimulants, 2004-2019; averaging 73 per year. Accidental poisonings accounted for 94% of cases. Methylphenidate was most frequently implicated (63%). Thirty-four per cent of cases were referred to hospital and a further 21% of calls were made by hospital staff. Poisoning exposure counts for all ADHD psychostimulants increased by 2.7% (95% CI=0.42% to 4.9%) per year; however, this differed by agent. Methylphenidate poisoning exposures increased by 5.2% per year (95% CI=4.3% to 6.1%), lisdexamfetamine increased by 62% per year (95% CI=48% to 76%), while dexamphetamine poisoning exposures decreased by 5.5% per year (95% CI=-9.5% to -1.4%). These trends are reflected in the number of dispensings; however, dispensings increased at a faster rate than exposures. When poisoning exposures were expressed as dispensing-adjusted rates, there was a 16% decrease (95% CI=-20% to -13%) per year.

CONCLUSIONS

ADHD medication use has increased, associated with an increased number of paediatric poisoning exposures. However, poisoning exposures per dispensed prescription has decreased. The majority of cases required hospitalisation, indicating the need for further poisoning prevention strategies.

Overdiagnosis of Attention-Deficit/Hyperactivity Disorder in Children and Adolescents: A Systematic Scoping Review

IMPORTANCE

Reported increases in attention-deficit/hyperactivity disorder (ADHD) diagnoses are accompanied by growing debate about the underlying factors. Although overdiagnosis is often suggested, no comprehensive evaluation of evidence for or against overdiagnosis has ever been undertaken and is urgently needed to enable evidence-based, patient-centered diagnosis and treatment of ADHD in contemporary health services.

OBJECTIVE

To systematically identify, appraise, and synthesize the evidence on overdiagnosis of ADHD in children and adolescents using a published 5-question framework for detecting overdiagnosis in noncancer conditions.

EVIDENCE REVIEW

This systematic scoping review adhered to the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) Extension for Scoping Reviews and Joanna Briggs Methodology, including the PRISMA-ScR Checklist. MEDLINE, Embase, PsychINFO, and the Cochrane Library databases were searched for studies published in English between January 1, 1979, and August 21, 2020. Studies of children and adolescents (aged ≤18 years) with ADHD that focused on overdiagnosis plus studies that could be mapped to 1 or more framework question were included. Two researchers independently reviewed all abstracts and full-text articles, and all included studies were assessed for quality.

FINDINGS

Of the 12 267 potentially relevant studies retrieved, 334 (2.7%) were included. Of the 334 studies, 61 (18.3%) were secondary and 273 (81.7%) were primary research articles. Substantial evidence of a reservoir of ADHD was found in 104 studies, providing a potential for diagnoses to increase (question 1). Evidence that actual ADHD diagnosis had increased was found in 45 studies (question 2). Twenty-five studies showed that these additional cases may be on the milder end of the ADHD spectrum (question 3), and 83 studies showed that pharmacological treatment of ADHD was increasing (question 4). A total of 151 studies reported on outcomes of diagnosis and pharmacological treatment (question 5). However, only 5 studies evaluated the critical issue of benefits and harms among the additional, milder cases. These studies supported a hypothesis of diminishing returns in which the harms may outweigh the benefits for youths with milder symptoms.

CONCLUSIONS AND RELEVANCE

This review found evidence of ADHD overdiagnosis and overtreatment in children and adolescents. Evidence gaps remain and future research is needed, in particular research on the long-term benefits and harms of diagnosing and treating ADHD in youths with milder symptoms; therefore, practitioners should be mindful of these knowledge gaps, especially when identifying these individuals and to ensure safe and equitable practice and policy.

Trends in incidence rates of diagnosed attention-deficit/hyperactivity disorder (ADHD) over 12 years in Taiwan: A nationwide population-based study

We investigated time trends in the incidence rate (IR) of attention-deficit/hyperactivity disorder (ADHD) across the lifespan and potential factors affecting them using a Taiwanese population-based database. IR per 10,000 person-years (PY) of newly diagnosed ADHD based on ICD-9-CM was calculated annually for the total population, gender, 5 age groups, and 3 ADHD subtypes from 2000 to 2011. Among the 265,932 patients, IR increased from 7.92 to 13.92; the male-to-female ratio decreased from 3.61 to 2.90. The largest increase in IR was noted in young adults (19-30 years), followed by preschoolers (0-6 years), while the smallest increase was in adults (>31 years). The IR trends showed a more prominent increase in males than females among children, adolescents, and young adults, yet a reserved relationship existed among adults, with a more prominent increase in women. The combined type of ADHD exhibited a prominently increasing trend in the child/adolescent group (age≦18) and the inattentive type ADHD in the adult group (age>18). In conclusion, the ADHD IR is increasing with distinct differences among age, sex, and subtypes. The diminishing gap between those who need treatment and those actually treated might partly contribute to this trend, especially among young adults, preschoolers, and females.

Determinants of inter-practice variation in ADHD diagnosis and stimulant prescribing: cross-sectional database study of a national surveillance network

Early recognition, identification and treatment of children with attention deficit hyperactivity disorder (ADHD) can reduce detrimental outcomes and redirect their developmental trajectory. We aimed to describe variations in age of ADHD diagnosis and stimulant prescribing among general practitioner practices in a nationwide network and identify child, parental, household and general practice factors that might account for these variations. Cross-sectional study of children aged under 19 years registered within a general practice in the Royal College of General Practitioners (RCGP) Research and Surveillance Centre (RSC) network in 2016, RCGP RSC has a household key allowing parent and child details to be linked. Data from 158 general practices and 353 774 children under 19 were included. The mean age of first ADHD diagnosis was 10.5 years (95% CI 10.1 to 10.9, median 10, IQR 9.0-11.9) and the mean percentage of children with ADHD prescribed stimulant medications among RCGP RSC practices was 41.2% (95% CI 38.7 to 43.6). There was wide inter-practice variation in the prevalence of diagnosis of ADHD, the age of diagnosis and stimulant prescribing. ADHD diagnosis is more likely to be made later in households with a greater number of children and with a larger age difference between adults and children. Stimulant prescribing for children with ADHD was higher in less deprived practices. Older parents and families with more children fail to recognise ADHD and may need more support. Practices in areas of higher socio-economic status are associated with greater prescribing of stimulants for children with ADHD.

Methylphenidate and atomoxetine prescribing trends in children in the Western Cape Province of South Africa, 2005-2013

Background

There is paucity of data on methylphenidate and atomoxetine prescribing patterns in South African children.

Aim

To describe the prescribing trends of these agents in children residing in the Western Cape Province.

Setting

South African private health sector.

Methods

Longitudinal drug utilisation study on medicine claims data from 2005–2013, focussing on the number of patients and prescriptions per patient.

Results

The total number of patients increased by 29.5% from 2005 to 2013. The majority were boys (male:female ratio, 3.5:1), and between the ages of > 6 and ≤12 years in 2005 and >12 and ≤18 years in 2013. More than 75% of patients received methylphenidate or atomoxetine in the City of Cape Town Metropolitan municipality. Prescriptions for methylphenidate and atomoxetine increased by 45.5% overall from 2005 to 2013 (p < 0.001), with that for methylphenidate and atomoxetine increasing by 36.0% and 314.5%, respectively. The average number of annual methylphenidate prescriptions per patient increased from 3.96 ± 2.92 (95% CI, 3.69–4.23) in 2005 to 4.38 ± 2.85 (95% CI, 4.14–4.61) in 2013 (Cohen’s d = 0.14) and for atomoxetine from 2.58 ± 1.86 (95% CI, 1.80–3.37) in 2005 to 4.85 ± 3.66 (95% CI, 3.84–5.86) in 2013 (Cohen’s d = 0.62).

Conclusion

Although the total number of patients and prescribing of methylphenidate and atomoxetine increased significantly from 2005 to 2013, a slight downward trend was observed in the mean number of prescriptions per patient per year from 2008 onwards. These prescribing patterns warrant further research.

ADHD Medication Trends in Turkey: 2009-2013

OBJECTIVE

To investigate the change of ADHD medication prescriptions in Turkey between 2009 and 2013.

METHOD

Consumption data of ADHD medications, immediate release (IR) methylphenidate (MPH; Ritalin), OROS MPH (Concerta), and atomoxetine (Strattera) were obtained from IMS Health database for the November 2008 to October 2013 period. Defined daily dose (DDD) of each drug was calculated according to WHO definitions and time-series analysis was conducted.

RESULTS

There was a significant seasonal effect for prescription of all drugs. Annual use of ADHD medications increased 2.18 times for all ADHD medications combined. DDDs per 1,000 population per day for all ADHD medications were 0.28 in 2009, 0.41 in 2010, 0.52 in 2011, and 0.59 in 2012. OROS MPH represented almost 75% of all ADHD medication utilization.

CONCLUSION

As reported from several other countries, ADHD medication use increased in Turkey. Results suggested that over- and underdiagnosis might be seen at the same time.

Heroic struggles, criminals and scientific breakthroughs: ADHD and the medicalization of child behaviour in Australian newsprint media 1999-2009

There is a dearth of scholarly analysis and critique of the Australian newsprint media’s role in the medicalization of child behaviour. To begin to redress this lack this paper analyses newsprint media’s use of metaphors that re/describe and construct realities of ADHD with a medicalizing effect. The interdisciplinary team used the Factiva^TM database to locate and review 453 articles published in Australian national and metropolitan newspapers during the decade 1999–2009. Data analysis involved generating statistical descriptions of the dataset according to attributes such as: date, state, newspaper titles and author names. This was followed by inductive analysis of article content. Content analysis revealed pervasive and striking use of metaphor in newsprint media reporting of ADHD content, especially when describing health professionals, educators, parents and children. This collection of metaphors was striking, and while the metaphors deployed were varied, this diversity seemed underscored by a common functionality that increased the risk that child behaviour was explained using medicalized knowledge. We contend that these metaphors collectively and coherently functioned to simplify and delimit meanings of children’s health and behaviour to favour depictions that medicalize problems of children and childhood.

Seeking Web-Based Information About Attention Deficit Hyperactivity Disorder: Where, What, and When

Background

Attention Deficit Hyperactivity Disorder (ADHD) is a common neurodevelopmental disorder, prevalent among 2-10% of the population.

Objective

The objective of this study was to describe where, what, and when people search online for topics related to ADHD.

Methods

Data were collected from Microsoft’s Bing search engine and from the community question and answer site, Yahoo Answers. The questions were analyzed based on keywords and using further statistical methods.

Results

Our results revealed that the Internet indeed constitutes a source of information for people searching the topic of ADHD, and that they search for information mostly about ADHD symptoms. Furthermore, individuals personally affected by the disorder made 2.0 more questions about ADHD compared with others. Questions begin when children reach 2 years of age, with an average age of 5.1 years. Most of the websites searched were not specifically related to ADHD and the timing of searches as well as the query content were different among those prediagnosis compared with postdiagnosis.

Conclusions

The study results shed light on the features of ADHD-related searches. Thus, they may help improve the Internet as a source of reliable information, and promote improved awareness and knowledge about ADHD as well as quality of life for populations dealing with the complex phenomena of ADHD.

[Time Trends in the Frequencies of ADHD and Stimulant Medication]

Time-trends in the frequencies of mental disorders represent specific challenges for the planning of services. The present review addresses the specific question whether or not there are time changes in terms of an increase of prevalence and incidence rates of attention-deficit hyperactivity disorders (ADHD) based on findings from international epidemiological studies from several decades. While there is no evidence that prevalence rates of ADHD have systematically increased, various national and international incidence studies on ADHD but also prevalence and incidence studies on prescribed medication indicate that the number of treated people with ADHD has increased significantly in the recent past. This increase remains even after adjusting for the general increase in the number of persons admitted to psychiatry for any disorder. Thus, the gap between those in need of treatment and those who actually receive treatment for ADHD has narrowed over time. However, after years of an increase, in recent years German studies dealing with prescriptions of medications have shown also a declining trend.

A Pilot Study for Understanding the Perceptions of Australian General Practitioners Regarding Psychopharmacology for Children With Autism Spectrum Disorders

BACKGROUND

General practitioners (GPs) are increasing involved in the care of children with autism spectrum disorders (ASDs), and prescribe and/or manage psychotropic medications for these children. Few published reports of perceptions of GPs regarding use of these medications exist in the literature.

OBJECTIVE

Qualitative analysis of comments by 177 GPs regarding psychopharmacology use in children with ASDs.

METHODS

A postal questionnaire survey containing both close- and open-ended questions was conducted in New South Wales, Australia.

RESULTS

Respondent GPs were more likely to be females graduated from Australian medical schools and reported an interest either in child or in mental health. The respondents demonstrated good understanding of the issues surrounding psychopharmacology use in children with ASD based on contemporary literature on this topic. The main themes included concerns regarding medication safety, evidence for their use, and role of these medications as an adjuvant to behavior management. GPs reported a lack of experience of these medications, and would often prescribe only under the supervision of specialists. GPs with greater confidence and involvement with children of ASDs prescribed more medications; whereas GP reporting more concerns with regard to medications prescribed less.

CONCLUSION

Respondent GPs have good understanding of psychotropic medications but need support from specialists for managing these medications in children with ASDs. Future larger studies should explore the utility of collaborative models of care for GPs to work in close partnerships with specialists.

Psychostimulant prescribing trends in a paediatric population in Ireland: a national cohort study

Background

Psychotropic paediatric prescribing trends are increasing internationally. The aim of this study is to examine the prevalence and secular trends in psychotropic prescribing in Irish children and adolescents between 2002 and 2011.

Methods

Data was obtained from the Irish General Medical Services (GMS) scheme pharmacy claims database from the Health Service Executive Primary Care Reimbursement Services (HSE-PCRS). Prescribing rates per 1000 eligible population and associated 95 % confidence intervals (CIs) were calculated across years (2002–2011), age groups (0–4, 5–11, 12–15 years) and gender. Rates of concomitant prescriptions for psycholeptics and antidepressants were also examined. The total expenditure costs were calculated and expressed as a percentage of the cost of all prescriptions for this age group (≤15 years).

Results

In 2002, 3.77/1000 GMS population (95 % CI: 3.53–4.01) received at least one psychostimulant prescription and this rate increased to 8.63/1000 GMS population (95 % CI: 8.34–8.92) in 2011. Methylphenidate was the most frequently prescribed psychostimulant. For both males and females the prevalence of medication use was highest among the 12–15 year old group. On average, a psycholeptic medication was prescribed to 8 % of all psychostimulant users and an antidepressant was concomitantly prescribed on average to 2 %. Total expenditure rose from €89,254 in 2002 to €1,532,016 in 2011.

Conclusions

The rate and cost of psychostimulant prescribing among GMS children and adolescents in Ireland increased significantly between 2002 and 2011. Further research is necessary to assess the safety, efficacy and economic impact of concomitant psychotropic prescribing in this population.

A Survival Analysis of Psychostimulant Prescriptions in New South Wales from 1990 to 2010

OBJECTIVE

Psychostimulant medication is considered a mainstay in the treatment of attention-deficit/hyperactivity disorder (ADHD); however, research suggests that the typical duration of medication treatment for children and youth may be <3 years. The purpose of this study was to evaluate the psychostimulant treatment persistence for children and adolescents in New South Wales, Australia.

METHODS

This study used survival analysis to assess duration of medication treatment on a large administrative database of children and youth from New South Wales, Australia. Several models were fit to evaluate differences in survival rates among decades (1990-1999 vs. 2000-2010), gender, and age.

RESULTS

Results showed that: 1) Overall median treatment time (i.e., median survival time) was 1.96 years (99% CI=1.93, 1.99); 2) there were small, but significant changes over time in duration of treatment; 3) females had shorter treatment duration than males; and 4) there were relatively large differences in treatment duration across age groups.

CONCLUSIONS

These results indicate that the majority of children and youth receive medication treatment for only a small portion of childhood/adolescence, and that there are differential patterns in treatment duration across age groups.

Psychostimulant prescription for ADHD in new South Wales: a longitudinal perspective

OBJECTIVE

There is a need for Australian studies of ADHD that utilize the individual child as the unit of analysis because they provide a more accurate picture of national patterns (in new prescriptions, start age, and duration). The aim of this study was to build toward a national picture of patterns in psychostimulant use for ADHD by undertaking a retrospective analysis of archival data on prescriptions within New South Wales (NSW), Australia's most populated state.

METHOD

A person-based data set was used to assess (a) rate of new prescriptions by age group, (b) demographic characteristics (age of start, male:female ratio), (c) duration of use, and (d) comparisons across the two decades.

RESULTS

Five findings were observed: (a) The prevalence of psychostimulant use was 1.24% in 2010, (b) there was significant variability in the rate of new prescriptions by age group after 2003, (c) start age declined over the 1990 to 2000 period, but began to increase from 2000 to 2010, (d) the male:female ratio declined, and (e) the duration of psychostimulant use declined consistently.

CONCLUSION

Results suggest disconnect between persistence across the life span and actual treatment patterns. A decline in medication treatment for more than 1 year and the growing proportion of discontinuous treatment suggests a need for strategies to assist families with the transition onto and off medications.

A systematic review of the application of spatial analysis in pharmacoepidemiologic research

PURPOSE

Although current reviews of the use of spatial analysis in general epidemiologic research illustrate an important and well-established role in exploring and predicting health, its application has not been reviewed in the subspecialty field of pharmacoepidemiology.

METHODS

We systematically reviewed the scientific literature to assess to what extent spatial analysis has been applied in pharmacoepidemiologic research and explored its potential added value.

RESULTS

A systematic search in PubMed and Embase/MEDLINE yielded 823 potentially relevant articles; 45 articles met our criteria for review. The studies were reviewed on study objective, applied spatial methods and units of analysis, and author-reported added value of the geographic approach used. Of the 45 included studies, 34 (76%) reported a geographic research objective. Comparative spatial methods were most often used (n = 25; 56%). Eleven studies used spatial statistics (32%); cluster analysis (n = 5) and aggregate data analysis (n = 4) being most common. Mapping was done in 15 studies (33%). The most common added value reported was to aid the planning of health policies and interventions (n = 24; 53%). A minority of pharmacoepidemiologic studies used a geographic approach and the applied methods were less advanced compared with the broader field of epidemiology.

CONCLUSIONS

Further advancements are needed to incorporate currently available spatial techniques to impact health care planning.

A review of geographic variation and Geographic Information Systems (GIS) applications in prescription drug use research

BACKGROUND

While understanding geography's role in healthcare has been an area of research for over 40 years, the application of geography-based analyses to prescription medication use is limited. The body of literature was reviewed to assess the current state of such studies to demonstrate the scale and scope of projects in order to highlight potential research opportunities.

OBJECTIVE

To review systematically how researchers have applied geography-based analyses to medication use data.

METHODS

Empiric, English language research articles were identified through PubMed and bibliographies. Original research articles were independently reviewed as to the medications or classes studied, data sources, measures of medication exposure, geographic units of analysis, geospatial measures, and statistical approaches.

RESULTS

From 145 publications matching key search terms, forty publications met the inclusion criteria. Cardiovascular and psychotropic classes accounted for the largest proportion of studies. Prescription drug claims were the primary source, and medication exposure was frequently captured as period prevalence. Medication exposure was documented across a variety of geopolitical units such as countries, provinces, regions, states, and postal codes. Most results were descriptive and formal statistical modeling capitalizing on geospatial techniques was rare.

CONCLUSION

Despite the extensive research on small area variation analysis in healthcare, there are a limited number of studies that have examined geographic variation in medication use. Clearly, there is opportunity to collaborate with geographers and GIS professionals to harness the power of GIS technologies and to strengthen future medication studies by applying more robust geospatial statistical methods.

Predictive factors for more than 3 years' duration of central stimulant treatment in adult attention-deficit/hyperactivity disorder: a retrospective, naturalistic study

There is effective short-term central stimulant (CS) treatment of attention-deficit/hyperactivity disorder (ADHD) symptoms in adult ADHD, and despite this, many patients discontinue the treatment too early. The present study examines the duration of CS treatment in a Norwegian cohort of adult ADHD to identify predictors for long treatment duration (≥ 3 years). The data were based on the medical records of a sample of 117 of all 119 adult ADHD patients diagnosed over a period of 8 years in a specific catchment area and treated with CS. A logistic regression model was applied to identify possible predictors for long treatment duration. The sample was severely impaired in terms of comorbidity, educational achievement, and employment. The median duration of CS treatment was 33.0 months. Use of extended-release formulations of methylphenidate predicted long treatment duration positively (odds ratio, 4.420 [95% CI, 1.875-10.419]), whereas baseline antisocial personality disorder predicted long treatment duration negatively (odds ratio, 0.210 [0.085-0.518]). This study showed that it is possible to treat severely impaired and highly comorbid adult ADHD patients with CS over years. The finding that extended-release formulations of methylphenidate predict long treatment duration supports previous research, and it is important to show this association in naturalistic samples such as in the present study. Comorbid antisocial personality disorder was a negative predictor of long CS treatment duration. Univariate analyses also indicate that comorbid substance use disorder is related to shorter duration of CS treatment.

Long-term effects of chronic oral Ritalin administration on cognitive and neural development in adolescent wistar kyoto rats

The diagnosis of Attention Deficit Hyperactivity Disorder (ADHD) often results in chronic treatment with psychostimulants such as methylphenidate (MPH, Ritalin^®). With increases in misdiagnosis of ADHD, children may be inappropriately exposed to chronic psychostimulant treatment during development. The aim of this study was to assess the effect of chronic Ritalin treatment on cognitive and neural development in misdiagnosed “normal” (Wistar Kyoto, WKY) rats and in Spontaneously Hypertensive Rats (SHR), a model of ADHD. Adolescent male animals were treated for four weeks with oral Ritalin^® (2 × 2 mg/kg/day) or distilled water (dH₂O). The effect of chronic treatment on delayed reinforcement tasks (DRT) and tyrosine hydroxylase immunoreactivity (TH-ir) in the prefrontal cortex was assessed. Two weeks following chronic treatment, WKY rats previously exposed to MPH chose the delayed reinforcer significantly less than the dH₂O treated controls in both the DRT and extinction task. MPH treatment did not significantly alter cognitive performance in the SHR. TH-ir in the infralimbic cortex was significantly altered by age and behavioural experience in WKY and SHR, however this effect was not evident in WKY rats treated with MPH. These results suggest that chronic treatment with MPH throughout adolescence in “normal” WKY rats increased impulsive choice and altered catecholamine development when compared to vehicle controls.

The diversion and misuse of pharmaceutical stimulants: what do we know and why should we care?

AIMS

To examine the literature pertaining to the diversion and misuse of pharmaceutical stimulants.

METHODS

Relevant literature was identified through comprehensive MEDLINE, EMBASE and PubMed searches.

RESULTS

The evidence to date suggests that the prevalence of diversion and misuse of pharmaceutical stimulants varies across adolescent and young adult student populations, but is higher than that among the general population, with the highest prevalence found among adults with attention deficit-hyperactive disorder (ADHD) and users of other illicit drugs. Concerns that these practices have become more prevalent as a result of increased prescribing are not supported by large-scale population surveys. Information on trends in misuse in countries where there have been recent increases in prescription and consumption rates, however, is limited. Little is known about the frequency and chronicity of misuse, or the extent of associated harms, particularly among those populations, i.e. adolescents, young adult student populations, those with ADHD and illicit drug users, where abuse may be more likely to occur.

CONCLUSIONS

Continued monitoring of the diversion and misuse of pharmaceutical stimulants is of major clinical importance. Despite recognition of the abuse liability of these medications, there is a paucity of data on the prevalence, patterns and harms of diversion and misuse among populations where problematic use and abuse may be most likely to occur (e.g. adolescents, young adults, illicit drug users). Comprehensive investigations of diversion and misuse among these populations should be a major research priority, as should the assessment of abuse and dependence criteria among those identified as regular users.

Australian national trends in stimulant dispensing: 2002-2009

OBJECTIVE

Internationally there has been an increase in the prescriptions of stimulant medication. The aim of this study was to examine longitudinal national trends of stimulant dispensing in Australia between 2002 and 2009.

METHOD

Government databases were retrospectively reviewed for all dispensed stimulant prescriptions between 2002 and 2009. Prescriptions were converted to defined daily dose (DDD)/1000 population/day using census data. Utilization of dexamphetamine and methylphenidate were analysed by source (subsidized or non-subsidized), prescriber (general practitioner, psychiatrist or other specialists), gender and age of patient.

RESULTS

Between 2002 and 2009, dispensing of stimulants in Australia increased 87% from 2.93 to 5.47 DDD/1000 population/day. Dexamphetamine remained the most commonly dispensed stimulant, with rates of dispensing falling 13% from 2.02 to 1.75 DDD/1000 population/day. Dispensed prescriptions of methylphenidate increased 300% from 0.45 in 2002 to 1.81 DDD/1000 population/day in 2009, attributable to the availability of long-acting preparations. Dispensing of stimulants to males was four-fold greater than to females. There was substantial dispensing of dexamphetamine to those older than 25 years.

CONCLUSIONS

Stimulant dispensing in Australia increased between 2002 and 2009 as a result of increased dispensing of long-acting preparations of methylphenidate. Further research is required to determine if the increase in stimulant dispensing in Australia is clinically appropriate.

Less discontinuation of ADHD drug use since the availability of long-acting ADHD medication in children, adolescents and adults under the age of 45 years in the Netherlands

Treatment options for ADHD in the Netherlands have increased with the introduction of the extended-release formulations of methylphenidate (MPH ER, Concerta^®) in 2003 and atomoxetine (ATX, Strattera^®) in 2005, but data on the effect on drug usage patterns are scarce. The objective of the present study was to describe changes in the patterns of ADHD medication use and determinants thereof among children, adolescents and adults (<45 years) starting ADHD medication since the introduction of MPH ER and ATX. Data were obtained from Dutch community pharmacies as collected by the Foundation for Pharmaceutical Statistics, covering 97% of all dispenses for prescription medicines to outpatients in the Netherlands. Usage patterns (continuation, discontinuation, switching and addition) of ADHD drugs were evaluated at 3, 6 and 12 months after initiation for three separate time cohorts (patients starting ADHD medication in Jan-Dec 2002, Jan 2003–June 2004, respectively July 2004–Dec 2005). It was found that between 2002 and 2006, most ADHD drug users were initiated on methylphenidate IR. Discontinuation of any ADHD drug treatment decreased over time partly in favour of switching and addition. Discontinuation at 3 months decreased from around 33% to around 25%, at 6 months from less than 50% to almost 35%, and at 12 months from just fewer than 60% to less than 45%. Discontinuation was higher among females and in adults >18 years. After the introduction of MPH ER and ATX (time cohort III), 16.5% of the incident ADHD drug users switched their medication and almost 9% added an ADHD drug to the prior ADHD drug. In conclusion, discontinuation of incident ADHD drug use is high after 3, 6 and 12 months. During the study period, the incidence of discontinuation decreased because of the availability of extended-release methylphenidate and atomoxetine.