Patterns and profiles of methylphenidate use both in children and adults

Methylphenidate use and restorative treatment needs in young adults with attention deficit hyperactivity disorder

OBJECTIVE

To assess the effect and dose-response of methylphenidate (MP) use on the restorative treatment needs in young adults with attention deficit hyperactivity disorder.

PARTICIPANTS AND METHODS

This retrospective study comprises a cohort of military recruits aged 18-25 who served for 12 to 48 months between 2005 and 2017. The medical records of 213 604 participants were assessed of which: 6875 participants with ADHD who received treatment with MP, 6729 participants with ADHD who had no prescriptions for MP, and 200 000 healthy participants. The outcome was restorative treatment needs, which served as an indicator of caries: having at least one prescription for restorative treatment during the study period.

RESULTS

Frequency of prescription for restorative treatment among the treated, the untreated and the control groups was 24%, 22%, and 17%, respectively (p < .0001). On multivariate analysis, the dose-response association between MP use and the odds of having at least one restorative treatment was confirmed (OR = 1.006 for each additional 1 gr of MP; 95% CI [1.004:1.009]) CONCLUSIONS: Participants with ADHD who receive chronic treatment with MP have higher restorative treatment needs than participants with untreated ADHD and healthy participants. Our results show that chronic MP medication among young adults leads to an elevated need for restorative treatment and implies a significant impact on oral health (OH).

Discontinuation of methylphenidate after long-term exposure in nonhuman primates

Attention-deficit hyperactivity disorder (ADHD) is a common human neurobehavioral disorder that usually begins in early childhood. Methylphenidate (MPH) has been used extensively as a first-line medicine for the treatment of ADHD. Since ADHD is often diagnosed in early childhood and can persist for the entire lifespan, individuals may take MPH for many years. Given that in the course of one's lifetime a person may stop taking MPH for periods of time, or may implement lifestyle changes that may reduce the need for MPH entirely, it is important to understand how cessation of MPH affects the adult brain following long-term use of MPH. The blockage of the dopamine transporter (DAT) and the norepinephrine transporter (NET) by MPH may help with ADHD symptoms by boosting monoamine levels in the synapse. In the present study, microPET/CT was used to investigate possible neurochemical alterations in the cerebral dopamine system after cessation of long-term MPH administration in nonhuman primates. MicroPET/CT images were collected from adult male rhesus monkeys 6 months after they stopped receiving vehicle or MPH following 12 years of chronic treatment. The neurochemical status of brain dopaminergic systems was evaluated using the vesicular monoamine transporter 2 (VMAT2) ligand [¹⁸F]-AV-133 and a tracer for imaging dopamine subtype 2 (D₂) and serotonin subfamily 2 (5HT₂) receptors, [¹⁸F]-FESP. Each tracer was injected intravenously and ten minutes later microPET/CT images were obtained over 120 min. The binding potential (BP) of each tracer in the striatum was obtained using the Logan reference tissue model with the cerebellar cortex time activity curve (TAC) as an input function. Brain metabolism was also evaluated using microPET/CT images of [¹⁸F]-FDG. [¹⁸F]-FDG was injected intravenously, and ten minutes later, microPET/CT images were obtained over 120 min. Radiolabeled tracer accumulation in regions of interest (ROIs) in the prefrontal cortex, temporal cortex, striatum, and cerebellum were converted into standard uptake values (SUVs). Compared to the vehicle control group, the BPs of [¹⁸F] AV-133 and [¹⁸F]-FESP in the striatum were not significantly altered in MPH treated groups. Additionally, no significant differences were detected in the SUVs of [¹⁸F]-FDG in the MPH treated group compared with control. This study demonstrates that 6 months after cessation of long-term, chronic MPH treatment, there are no significant neurochemical or neural metabolic changes in the central nervous system (CNS) of non-human primates (NHPs) and suggests that microPET imaging is helpful in assessing the status of biomarkers of neurochemical processes linked to chronic CNS drug exposure. (Supported by NCTR).

Methylphenidate cross-sensitization with amphetamine is dose dependent but not age dependent

Psychostimulants such as methylphenidate (MPD) and amphetamine (AMP) are often prescribed to young children and adolescents to treat behavioral disorders, or used to improve their intellectual performance in our competitive society. This is concerning as the temporal effects of how MPD exposure at a young age influences the response to MPD and AMP administration later in adulthood remains unclear. The objective of this study was to test whether MPD has the characteristics of substances that elicit behavioral symptoms of dependence and whether those effects are influenced by the initial age of MPD exposure. Three control and nine experimental groups of male rats were used. They were exposed to repetitive (chronic) 0.6, 2.5, or 10.0 mg/kg MPD in adolescence only, adulthood only, or adolescence and adulthood respectively. Then all groups were subsequently re-challenged with a single AMP dose in adulthood to test whether cross-sensitization between MPD and AMP was expressed, potentially as a result of prior MPD consumption. Exposure to 2.5 mg/kg and 10.0 mg/kg MPD in adolescence and adulthood or in adulthood alone led to cross-sensitization with AMP while exposure to 0.6 mg/kg MPD in adolescence and adulthood or in adulthood alone did not lead to cross-sensitization with AMP. Thus, these results indicate that MPD cross-sensitization with AMP is dose dependent.

Long-term methylphenidate use for children and adolescents with attention deficit hyperactivity disorder and risk for depression, conduct disorder, and psychotic disorder: a nationwide longitudinal cohort study in South Korea

BACKGROUND

Methylphenidate (MPH) is the most frequently prescribed medication for the treatment of attention deficit hyperactivity disorder (ADHD). However, the safety of its long-term use remain unclear. In particular, real-world evidence of long-term MPH treatment regarding the risk of depression, conduct disorders, and psychotic disorders in children and adolescents is needed. This study aimed to compare the risks of depression, conduct disorder, and psychotic disorder between long- and short-term MPH treatments in children and adolescents.

METHODS

This population-based cohort study used a nationwide claims database of all patients with ADHD in South Korea. Patients aged less than 18 years who were prescribed MPH were included in the study. Long- and short-term MPH were defined as > 1 year, and < 1 year, respectively. Overall, the risk of developing depressive disorder, conduct disorder and oppositional defiant disorder (ODD), and psychotic disorder were investigated. A 1:2 propensity score matching was used to balance the cohorts, and the Cox proportional hazards model was used to evaluate the safety of MPH.

RESULTS

We identified 1309 long-term and 2199 short-term MPH users. Long-term MPH use was associated with a significantly lower risk of depressive (hazard ratio [HR], 0.70 [95% confidence interval [CI] 0.55-0.88]) and conduct disorders and ODD (HR, 0.52 [95% CI 0.38-0.73]) than short-term MPH use. Psychotic disorder was not significantly associated with long-term MPH use (hazard ratio [HR], 0.83 [95% confidence interval [CI] 0.52-1.32]).

CONCLUSIONS

Our findings suggest that long-term MPH use may be associated with a decreased risk of depression, conduct disorders and ODD. Moreover, the long-term use of MPH does not increase the risk of psychotic disorders. Long-term MPH administration may be considered as a favourable treatment strategy for children and adolescents with ADHD regarding depressive, conduct, and psychotic disorders.

Increased sperm DNA damage leads to poor embryo quality and subfertility of male rats treated with methylphenidate hydrochloride in adolescence

BACKGROUND

Methylphenidate hydrochloride (MPH) is a psychostimulant widely used in the treatment of attention deficit hyperactive disorder (ADHD), as well as a performance enhancer, for at least 60 years. Despite the notable effectiveness as a psychostimulant, ADHD is a chronic disorder and has a two-third chance of accompanying the individual throughout life. Long-term use of MPH has been associated not only with an increase in the development of neurodegenerative diseases, but it also has side effects on male fertility in experimental animals.

OBJECTIVES

To investigate whether methylphenidate poses a risk to sperm DNA structure and to the quality of embryos conceived after treatment during adolescence in rats.

MATERIALS AND METHODS

Wistar rats at 38 days of age were treated either with 5 mg/kg body weight of MPH, in a single daily dose for 30 days, via gavage or with distilled water-only protocol. Levels of oxidative stress in testicular and epididymal tissues were evaluated. Sperm chromatin quality and acrosome integrity was assessed under flow cytometry. From 107 days of age, animals were mated with untreated females. The effects of the paternal contribution at two different embryo development moments - cleavage stage (2.5 days post coitum) and late gestation (20 days post coitum) - were analyzed.

RESULTS

MPH caused high levels of sperm DNA damage, which was reflected in 40% of decrease in early embryo quality and a lower number of live pups at 20 dpc.

DISCUSSION

The high level of fragmentation seen in the embryos sired from the MPH group is consistent with the poor chromatin structure of the sperm, and does not seem to be a result of oxidative stress in the reproductive tissues.

CONCLUSIONS

The results presented here suggest that the subchronic use of MPH during male prepubertal phase may cause long term subfertility and compromise embryo survival. This article is protected by copyright. All rights reserved.

ADHD diagnosis and methylphenidate consumption in children and adolescents: A systematic analysis of health databases in France over the period 2010-2019

CONTEXT

ADHD is the most common mental disorder in school-aged children. In France, methylphenidate is the only drug authorized for ADHD. Here, we describe the pattern of ADHD diagnosis and methylphenidate prescription to children and adolescents from 2010 to 2019.

METHODS

We conducted a retrospective cohort study of all beneficiaries of the French general health insurance scheme (87% of the population, 58 million people). We extracted information for all children and adolescents aged 0-17 years who received: (1) A diagnosis of ADHD (34,153 patients). (2) At least one methylphenidate prescription (144,509 patients). We analyzed the clinical, demographic, institutional, and social parameters associated with ADHD diagnosis and methylphenidate consumption in France.

RESULTS

The ADHD diagnosis among children and adolescents increased by 96% between 2010 and 2019. ADHD diagnosis affects more boys than girls. About 50.6% of children hospitalized with a diagnosis of ADHD in 2017 also had another psychiatric diagnosis. The rate of children hospitalized with an ADHD diagnosis and treated with MPH varied between 56.4 and 60.1%. The median duration of MPH treatment for a 6-year-old ADHD child initiated in 2011 is 7.1 years. In 2018, 62% of ADHD children were receiving at least one psychotropic medication. Between 2010 and 2019, methylphenidate prescription increased by +56% for incidence and +116% for prevalence. The prevalence of methylphenidate prescription reached between 0.61 and 0.75% in 2019. Boys are predominantly medicated. The median duration of treatment among 6-year-olds in 2011 was 5.5 years. The youngest children received the longest treatment duration. Diagnoses associated with methylphenidate prescription did not always correspond to the marketing authorization. Among children receiving the first prescription of methylphenidate, 22.8% also received one or more other psychotropic drugs during the same year. A quarter of initiations and half of renewals were made outside governmental recommendations. Educational and psychotherapeutic follow-up decreased from 4.1% in 2010 to 0.8% in 2019. French children and adolescents, who were the youngest in their class were more likely to be diagnosed (55%) and prescribed methylphenidate (54%). Children from disadvantaged families had an increased risk of ADHD diagnosis (41.4% in 2019) and methylphenidate medication (25.7% in 2019).

Methylphenidate for attention-deficit/hyperactivity disorder in adults: a narrative review

RATIONALE

Psychostimulants, including methylphenidate (MPH), are the mainstay of pharmacotherapy for attention-deficit/hyperactivity disorder (ADHD) in adults. Even though MPH is the most commonly used medication for ADHD these days, there are relatively few resources available that provide comprehensive insight into the pharmacological and clinical features of the compound.

OBJECTIVE

The aim of this paper is to provide an up-to-date outline of the pharmacology and clinical utility of MPH for ADHD in adult patients.

METHODS

While conducting the narrative review, we applied structured search strategies covering the two major online databases (MEDLINE and Cochrane Central Register of Controlled Trials). In addition, we performed handsearching of reference lists of relevant papers.

RESULTS

Methylphenidate exhibits multimodal mechanism of action, working primarily as a dopamine and noradrenaline reuptake inhibitor. It also protects the dopaminergic system against the ongoing 'wearing off' (by securing a substantial reserve pool of the neurotransmitter, stored in the presynaptic vesicles). In placebo-controlled trials, MPH was shown to be moderately effective both against the core ADHD symptoms (standardized mean difference [SMD], 0.49; 95% confidence interval [CI], 0.35-0.64), and the accompanying emotion regulation deficits (SMD, 0.34; 95% CI, 0.23-0.45). The most common adverse events related to long-term treatment with MPH are decreased appetite (~ 20%), dry mouth (15%), heart palpitations (13%), gastrointestinal infections (~ 10%), and agitation/feeling restless (~ 10%).

CONCLUSIONS

There is substantial body of evidence to suggest that MPH is an effective and safe treatment option for adults with ADHD.

Druggable genome in attention deficit/hyperactivity disorder and its co-morbid conditions. New avenues for treatment

Attention-Deficit/Hyperactivity Disorder (ADHD) is a common neurodevelopmental disorder with only symptomatic care available. Genome-wide association (GWA) studies can provide a starting point in the search for novel drug targets and possibilities of drug repurposing. Here, we explored the druggable genome in ADHD by utilising GWA studies on ADHD and its co-morbid conditions. First, we explored whether the genes targeted by current ADHD drugs show association with the disorder and/or its co-morbidities. Second, we aimed to identify genes and pathways involved in the biological processes underlying ADHD that can be targeted by pharmacological agents. These ADHD-associated druggable genes and pathways were also examined in co-morbidities of ADHD, as commonalities in their aetiology and management may lead to novel pharmacological insights. Strikingly, none of the genes encoding targets of first-line pharmacotherapeutics for ADHD were significantly associated with the disorder, suggesting that FDA-approved ADHD drugs may act through different mechanisms than those underlying ADHD. In the examined druggable genome, three loci on chromosomes 1, 4 and 12 revealed significant association with ADHD and contained nine druggable genes, five of which encode established drug targets for malignancies, autoimmune and neurodevelopmental disorders. To conclude, we present a framework to assess the druggable genome in a disorder, exemplified by ADHD. We highlight signal transduction and cell adhesion as potential novel avenues for ADHD treatment. Our findings add to knowledge on known ADHD drugs and present the exploration of druggable genome associated with ADHD, which may offer interventions at the aetiological level of the disorder.

Evolution of doctor shopping for oxycodone in the 67 million inhabitants in France as a proxy for potential misuse or abuse

ABSTRACT

This nationwide study aimed to compare use of oxycodone and doctor shopping for oxycodone in 2010 and 2016, and to quantify doctor shopping for oxycodone by sex, age, formulation, and dosage in 2010 and 2016. This study is a cross-sectional comparative analysis of doctor shopping based on all dispensings of oxycodone in France, in 2010 and 2016. Dispensings of oxycodone were extracted from the Système national des données de santé, which covers the 67 million inhabitants in France. Quantification of doctor shopping relies on an algorithm accounting for overlapping prescriptions, which is a proxy for potential misuse or abuse. The number of subjects who received oxycodone increased by 214% from 67,838 subjects in 2010 to 212,753 subjects in 2016, and the number of subjects with doctor-shopping behavior increased by 197%, from 1066 subjects in 2010 to 3163 subjects in 2016. For 30- to 44-year-old men, the total quantity of oxycodone obtained by doctor shopping increased by 391%, from 4582 defined daily doses in 2010 to 22,517 defined daily doses in 2016. By formulation and dosage, the total quantity of oxycodone obtained by doctor shopping increased with the dosage for both immediate-release and extended-release tablets in 2010 and 2016. The widespread extent of doctor shopping and its 3-fold increase in line with population exposure is a strong signal in the French context. These results are another argument to avoid trivializing oxycodone to prevent misuse, potential abuse, and potential oxycodone-related deaths, but it requires caution to prevent compromising effective treatment of pain.

First-Time Users of ADHD Medication Among Children and Adolescents in Germany: An Evaluation of Adherence to Prescribing Guidelines Based on Claims Data

Background: Drug utilization studies based on real-world data are vital for the identification of potentially needed improvements to rational prescribing. This is particularly important for the pharmacological treatment of children and adolescents with attention-deficit hyperactivity disorder (ADHD) due to the associated potential side effects and the frequent use. Whereas prevalent use is well-characterized, studies on first-time use of ADHD medication are scarce. This study aimed to evaluate off-label prescribing in first-time users of ADHD medication among children and adolescents in Germany based on three criteria: (i) lack of a documented ADHD diagnosis; (ii) first-time pharmacological treatment with a second-line drug; and (iii) patient age below 6 years. Methods: Based on German claims data, we included children and adolescents aged 0-17 years with a first-time dispensation of any ADHD medication in the period 2015-2017. These first-time users were characterized with regard to sex, age, specialty of the prescribing physician, documentation of an ADHD diagnosis, psychiatric hospitalization, psychiatric comorbidities, and history of other psychopharmacological drugs at first-time use. Results: The study population comprised 18,703 pediatric first-time users of ADHD medication. Of these, 9.8% had no documented ADHD diagnosis. Most of the ADHD drug users received first-line ADHD pharmacotherapy (methylphenidate, atomoxetine), whereas 2.6% were prescribed second-line ADHD medication (lisdexamfetamine, guanfacine, dexamfetamine, multiple ADHD drugs) as first drug. Overall, 1.2% of first-time users were aged below 6 years. A total of 12.7% of the study population met any off-label criterion. Conclusions: About 13% of pediatric first-time users of ADHD medication in Germany received an off-label pharmacotherapy at first-time use. Prescribing ADHD medication without a confirmed ADHD diagnosis was the most common of the three assessed off-label criteria. Off-label prescribing regarding drug choice and age of patients only occurred in a small percentage of initial pharmacological ADHD treatment. Our results suggest the need for improvement in rational prescribing, especially with regard to diagnostic requirements.

Doctor shopping for methylphenidate as a proxy for misuse and potential abuse in the 67 million inhabitants in France

Doctor shopping enables subjects to receive more than the prescribed dose out of any medical management, which suggests a search for high doses and makes doctor shopping a relevant proxy for misuse and potential abuse. Therefore, this study aimed to identify and characterize profiles of subjects with doctor-shopping behavior for methylphenidate in the entire French population. This study is a cross-sectional study of doctor-shopping behavior for methylphenidate in France, in 2016, using the Système national des données de santé, and accounting for overlapping prescriptions. Subjects who obtained >840 mg by doctor shopping were defined as subjects with heavy doctor-shopping behavior, and subjects who obtained >0 mg and ≤840 mg by doctor shopping were defined as subjects with light doctor-shopping behavior. A total of 63 739 subjects were included, and received 339.6 kg of methylphenidate. Among them, 216 (0.3%) subjects had heavy doctor-shopping behavior, and 313 (0.5%) subjects had light doctor-shopping behavior. Compared with subjects with light doctor-shopping behavior, subjects with heavy doctor-shopping behavior were older (64% of 30- to 49-year-old subjects vs. 77% of ≤17-year-old subjects; P < 0.001), received more concomitant dispensings of antipsychotics (37% vs. 26%; P = 0.008) and opioid maintenance treatments (50% vs. 6%; P < 0.001), and had more prescribers (4 [IQR = 2-5] vs. 2 [IQR = 2-3]; P < 0.001). In the French context where prescription and dispensing of methylphenidate are highly regulated and methylphenidate is much less used than in other countries, these results are a warning signal to avoid trivializing methylphenidate in adults.

Trends in stimulant dispensing by age, sex, state of residence, and prescriber specialty - United States, 2014-2019

BACKGROUND

Stimulant medications are commonly prescribed for the treatment of attention-deficit/hyperactivity disorder; however, they also have high potential for diversion and misuse. We estimated national stimulant dispensing trends from 2014 to 2019 and differences in dispensing by age, sex, state, prescriber specialty, payor type, patient copay, and stimulant type.

METHODS

We calculated rates of stimulant dispensing using IQVIA National Prescription Audit (NPA) New to Brand, NPA Regional, and NPA Extended Insights data, which provide dispensing estimates from approximately 49,900 pharmacies representing 92 % of prescriptions dispensed in the United States. Average annual percent change (AAPC) from 2014 to 2019 was analyzed using Joinpoint regression.

RESULTS

From 2014 to 2019, the national annual rate of stimulant dispensing increased significantly from 5.6 to 6.1 prescriptions per 100 persons. Rates differed by prescription stimulant type, with increases occurring among both amphetamine-type stimulants and long-acting stimulants. Rates among females (AAPC = 3.6 %; P = 0.001) and adults aged 20-39 years (AAPC=6.7 %; P = 0.002), 40-59 years (AAPC=9.7 %; P < 0.001), and ≥60 years (AAPC = 6.9 %; P = 0.001) increased significantly during the study period. Stimulant dispensing rates varied substantially across states, ranging from 1.0 per 100 in Hawaii to 13.6 per 100 in Alabama.

CONCLUSIONS

National stimulant dispensing rates increased from 2014 to 2019, driven by notable increases among females and adults aged ≥20 years. These trends should be considered when prescribing stimulants given growing concerns over prescription stimulant diversion, misuse, and related health harms.

Short term methylphenidate treatment does not increase myocardial injury in the ischemic rat heart

Methylphenidate is commonly used for the treatment of attention deficit hyperactivity disorder. The cardiovascular safety of methylphenidate has been a subject of debate with some studies indicating that methylphenidate increases the likelihood of experiencing a myocardial infarction. However, it is unknown whether methylphenidate worsens the extent of injury during an ischemic insult. The purpose of this study was to determine whether short term exposure to methylphenidate increases the extent of myocardial injury during an ischemic insult. Male and female rats received methylphenidate (5 mg/kg/day) or saline for 10 days by oral gavage. Hearts were subjected to 20 min of ischemia and 2 h of reperfusion on a Langendorff isolated heart apparatus on day 11. Cardiac contractile function was monitored via an intraventricular balloon and myocardial injury was assessed by triphenyltetrazolium chloride staining. Methylphenidate significantly increased locomotor activity in male and female rats, confirming absorption of this psychostimulant into the central nervous system. Male hearts had significantly larger infarcts than female hearts, but methylphenidate had no impact on infarct size or postischemic recovery of contractile function in hearts of either sex. These data indicate that methylphenidate does not increase the extent of injury induced by an ischemic insult.

Patterns of Lisdexamfetamine Dimesylate Use in Children, Adolescents, and Adults with Attention-Deficit/Hyperactivity Disorder in Europe

Objectives: Lisdexamfetamine dimesylate (LDX) is approved in some European countries for the second-line treatment of attention-deficit/hyperactivity disorder (ADHD) in children and adolescents when response to previous methylphenidate (MPH) treatment is considered clinically inadequate, and as a first-line treatment in adults. Limited evidence exists on the real-world use of LDX across Europe. This retrospective study evaluated LDX drug utilization patterns from eight European countries for up to 5 years. Methods: Data were collected from national registries (Denmark, Finland, Norway, Sweden), electronic medical records (Germany, Spain, United Kingdom), and prescription databases (Switzerland) in eight European countries. Patients were included if they were prescribed LDX at least once since the LDX launch date in each country. Demographic and clinical characteristics, and LDX prescription data included patient age and gender, a recorded diagnosis of ADHD, the number of prescriptions per participant, previous MPH prescription recorded, average daily dose, treatment persistence, discontinuation, and switching of medications. Results: Overall, information for 59,292 patients (437,272 LDX prescriptions) was analyzed. Most patients were male (58.1%-84.3%) and fewer than 1% were under 6 years of age. Extensive use of LDX in adults was observed in four countries (Denmark, Finland, Norway, and Sweden), including countries where LDX was not approved for this age group. Most patients had a recorded diagnosis of ADHD (61.9%-95.4%). The mean number of prescriptions per patient ranged from 5.4 to 10.0. At least 79.6% of patients with ADHD had a recorded previous MPH prescription. Mean duration of LDX exposure ranged from 233.1 to 410.8 days. The average daily dose of LDX was ≤70 mg/day for most patients (79.4%-99.7%). The 5-year discontinuation rate ranged from 22.8% to 70.6% and was below 40% for most countries. The proportion of patients switching from LDX to other medications was ≤33.8. Conclusions: This study provides the first long-term, real-world information related to LDX use by children, adolescents, and adults in Europe in the 5 years since its first launch in the region. Most LDX prescriptions fulfilled label requirements regarding a recorded diagnosis of ADHD before treatment initiation, previous MPH use, and an average daily dose of ≤70 mg/day. LDX was largely prescribed within the indicated age range, although adult use of LDX was high in some countries where LDX is not approved for this population.

The 10-year trend in drug prescriptions for attention-deficit/hyperactivity disorder (ADHD) in Germany

Purpose

The aim of this study was to analyse whether the global trend in drug prescriptions for attention-deficit hyperactivity disorders (ADHD), as observed during the last years and often criticized as medicalization, have remained stable or shifted.

Methods

This observational study was based on a secondary analysis of data from a large German database including patients with an ADHD diagnosis between 2008 and 2018. Prescription data comprised all important ADHD drugs.

Results

A total of 620 practices delivered data from a total of 77,504 patients (31% of them females) with a diagnosis of AHDH. Nearly 38% (29,396/77,504) of all patients received, at least, one prescription for an ADHS medicine between 2008 and 2018. The number of patients receiving a drug steadily increased annually until 2012 and then slowly fell, but unevenly distributed across the age groups. While the number of younger patients ( ≤ 16 years) receiving a prescription fell by 24% and the defined daily doses (DDDs) remained stable, the number of patients between 17 and 24 years receiving a prescription increased by 113% and the DDDs by 150%. Respectively, the number of older adults (≥ 25 years) with a prescription increased by 355% and the DDDs by 515%. Nearly one-third of older adults received an ADHD medicine only once.

Conclusion

The ever-increasing prescription of ADHD medicines stopped some years ago for children. ADHS and its pharmacological management are increasingly observed among older adolescents and adults, with a different pattern of drug persistence compared with children.

Electronic supplementary material

The online version of this article (10.1007/s00228-020-02948-3) contains supplementary material, which is available to authorized users.

Trends in attention-deficit and hyperactivity disorder (ADHD) medications among children and young adults in Ireland: a repeated cross-sectional study from 2005 to 2015

OBJECTIVE

This study examined the prescribing patterns of attention-deficit hyperactivity disorder (ADHD) medications in Ireland between 2005 and 2015 in children, adolescents and young adults, and concomitant use of psychotropic medication.

DESIGN

Repeated cross-sectional study.

SETTING

Community setting using pharmacy claims data in Ireland.

PARTICIPANTS

Children and young adults aged 0-24 years.

PRIMARY AND SECONDARY OUTCOMES

Authorised medications used to treat ADHD during the study period, methylphenidate, dexamfetamine, lisdexamfetamine dimesylate and atomoxetine were extracted from a national pharmacy claims database. Dispensing of concomitant psychotropic medications including antipsychotics, anxiolytics, hypnotics/sedatives and antidepressants were examined.

RESULTS

The number on any ADHD medication ranged from 1913 in 2005 to 4853 in 2015, and the prevalence rate per 1000 eligible population aged <25 years increased significantly over time from 5.61 (95% CI 5.36 to 5.86) in 2005 to 8.36 (95% CI 8.13 to 8.60) in 2015 (p<0.0001). Negative binomial regression showed significant changes over time for ADHD prescribing (p<0.001), with significantly higher rates across the different age groups. The rates overall were three to five times higher in males. There was a significant increase in the percentage on concomitant antidepressants from 2% in 2005 to 6% in 2015 (p<0.001).

CONCLUSIONS

There were significantly higher rates of ADHD prescribing in children/adolescents and a significant increase in the coprescribing of antidepressants. The reasons for the increase are unclear but may reflect increasing awareness and diagnosis of the condition.

Glutaminergic signaling in the caudate nucleus is required for behavioral sensitization to methylphenidate

Methylphenidate (MPD) is a widely prescribed psychostimulant for the treatment of attention deficit hyperactivity disorder, and is growing in use as a recreational drug and academic enhancer. MPD acts on the reward/motive and motor circuits of the CNS to produce its effects on behavior. The caudate nucleus (CN) is known to be a part of these circuits, so a lesion study was designed to elucidate the role of the CN in response to acute and chronic MPD exposure. Five groups of n = 8 rats were used: control, sham CN lesions, non-specific electrolytic CN lesions, dopaminergic-specific (6-OHDA toxin) CN lesion, and glutaminergic-specific (ibotenic acid toxin) CN lesions. On experimental day (ED) 1, all groups received saline injections. On ED 2, surgeries took place, followed by a 5-day recovery period (ED 3-7). Groups then received six daily MPD 2.5 mg/kg injections (ED 9-14), then three days of washout with no injection (ED 15-17), followed by a re-challenge with the previous 2.5 mg/kg MPD dose (ED 18). Locomotive activity was recorded for 60 min after each injection by a computerized animal activity monitor. The electrolytic CN lesion group responded to the MPD acute and chronic exposures similarly to the control and sham groups, showing an increase in locomotive activity, i.e. sensitization. The dopaminergic-specific CN lesion group failed to respond to MPD exposure both acute and chronically. The glutaminergic-specific CN lesion group responded to MPD exposure acutely but failed to manifest chronic effects. This confirms the CN's dopaminergic system is necessary for MPD to manifest its acute and chronic effects on behavior, and demonstrates that the CN's glutaminergic system is necessary for the chronic effects of MPD such as sensitization. Thus, the dopaminergic and glutaminergic components of the CN play a significant role in differentially modulating the acute and chronic effects of MPD respectively.

Pharmacoepidemiological research for the development and evaluation of drugs in pediatrics

New regulations have come into force in Europe and the US establishing the pediatric development as an integral part of the early development of medicinal products. Parallel to the advances in pediatric clinical research, it became obvious that all available sources and research tools to gather valuable information for the safe and efficacious prescription of medicines in children should be used. Real-life, pharmacoepidemiological studies provide information that contribute to the better knowledge of drug utilization, effects and safety in the pediatric population and thereby, a better prescribing in children. In this paper, we suggest some possible applications, provide examples of impact of pharmacoepidemiological and pharmacovigilance studies and expose future perspectives in pediatric pharmacoepidemiology.

Simultaneous determination of methylphenidate and ritalinic acid in hair using LC-MS/MS

Methylphenidate (MPH) is one of the most commonly prescribed stimulants for attention deficit hyperactivity disorder and its abuse is on the rise with its growing availability. Some analytical methods have been reported for the detection of MPH in hair. However, the concentration range of MPH as well as its metabolite, ritalinic acid (RA) in the hair of MPH abuse cases has not been reported. In this study, a sensitive and reliable liquid chromatography-tandem mass spectrometry method was developed and validated for the simultaneous determination of MPH and RA in hair. Sample preparation was carried out by a simple methanol extraction using 10mg of hair. Limits of detection for MPH and RA in hair were 0.5pg/mg and 1pg/mg, respectively, and the limits of quantification (LOQs) were 1pg/mg for both the analytes. Validation results showed good linearity in the range of 1-100pg/mg with acceptable precision and accuracy. The developed method was applied to real hair samples obtained from ten drug users who obtained MPH illegally without a prescription. MPH concentrations in the hair samples ranged from 1.0pg/mg to 265.0pg/mg, and RA was present at concentrations <LOQ-76.3pg/mg. In this study, hair analysis and background findings revealed that most subjects have abused illicit substances (methamphetamine, Δ⁹-tetrahydrocannabinol, zolpidem etc.) other than MPH. The low picogram range of LODs for MPH and RA in hair was achieved with the present method and the results from real sample analysis would provide useful information related to MPH abuse under forensic settings.

Overuse of methylphenidate: an analysis of Swedish pharmacy dispensing data

PURPOSE

To identify overuse of methylphenidate and to investigate patterns of overuse in relation to sociodemographic and clinical characteristics.

PATIENTS AND METHODS

Swedish national, pharmacy dispensing data were analyzed for all 56,922 individuals aged 6-79 years, who filled a methylphenidate prescription between 2010 and 2011. Overuse was defined as having above 150% days covered by the dispensed amount during 365 days from the first prescription fill, assuming use at the maximum recommended daily dose.

RESULTS

In total, 4,304 individuals (7.6% of the methylphenidate users) were categorized as overusers. The risk of overuse increased with age (OR for 46-65 years vs 6-12 years 17.5, 95% CI 14.3-21.3), and was higher in men (OR 1.4, 95% CI 1.3-1.5) and individuals with low income (OR 1.1, 95% CI 1.0-1.2), as well as in individuals with an attention deficit hyperactivity disorder (ADHD) diagnosis (OR 1.4, 95% CI 1.3-1.6), health care visits (OR 1.3, 95% CI 1.2-1.4), previous ADHD medication use (OR 2.6, 95% CI 2.4-2.8), and previous diagnosis of mental and behavioral disorders due to psychoactive substance use (OR 2.1 95% CI 2.0-2.3).

CONCLUSION

Among individuals using methylphenidate in Sweden, 7.6% receive amounts that are larger than what they should have a medical need for, assuming that they were using the maximum recommended daily dose 365 days per year. Notably, the prevalence of overuse was associated with previous diagnosis of alcohol and drug misuse. The prevalence was also positively associated with higher age and previous use of ADHD medication. These findings may point toward a link between exposure time and overuse. However, future studies with long-term data are needed to investigate this.

Attention-Deficit/Hyperactivity Disorder and Transitional Aged Youth

PURPOSE OF REVIEW

Extensive research has been conducted on attention-deficit/hyperactivity disorder (ADHD) in children and adults; however, less is known about ADHD during the transition from childhood to adulthood. Transitional aged youth (TAY) with ADHD represents a particularly vulnerable population as their newfound independence and responsibility often coincides with the development of comorbid disorders. The purpose of this review is to provide an update on the evaluation, diagnosis, and treatment of TAY-ADHD.

RECENT FINDINGS

Recent studies discovering ADHD symptoms emerging in TAY call the classification of ADHD as a disorder necessarily developing in childhood into question. TAY-ADHD are also shown to be vulnerable to academic and social impairments, increased risky behavior, and comorbid psychiatric disorders. Due to the risk of stimulant diversion in TAY, providers are advised to take precaution when prescribing medication to this population. Recent studies demonstrating the efficacy of psychotherapy in conjunction with non-stimulant or extended release stimulant medication provide a feasible alternative. This review highlights research on the course and evaluation of ADHD, impairments and comorbidities specific to TAY, and treatments tailored to address the unique challenges associated with TAY-ADHD.

The Intersection of Central Dopamine System and Stroke: Potential Avenues Aiming at Enhancement of Motor Recovery

Dopamine, a major neurotransmitter, plays a role in a wide range of brain sensorimotor functions. Parkinson's disease and schizophrenia are two major human neuropsychiatric disorders typically associated with dysfunctional dopamine activity levels, which can be alleviated through the druggability of the dopaminergic systems. Meanwhile, several studies suggest that optimal brain dopamine activity levels are also significantly impacted in other serious neurological conditions, notably stroke, but this has yet to be fully appreciated at both basic and clinical research levels. This is of utmost importance as there is a need for better treatments to improve recovery from stroke. Here, we discuss the state of knowledge regarding the modulation of dopaminergic systems following stroke, and the use of dopamine boosting therapies in animal stroke models to improve stroke recovery. Indeed, studies in animals and humans show stroke leads to changes in dopamine functioning. Moreover, evidence from animal stroke models suggests stimulation of dopamine receptors may be a promising therapeutic approach for enhancing motor recovery from stroke. With respect to the latter, we discuss the evidence for several possible receptor-linked mechanisms by which improved motor recovery may be mediated. One avenue of particular promise is the subtype-selective stimulation of dopamine receptors in conjunction with physical therapy. However, results from clinical trials so far have been more mixed due to a number of potential reasons including, targeting of the wrong patient populations and use of drugs which modulate a wide array of receptors. Notwithstanding these issues, it is hoped that future research endeavors will assist in the development of more refined dopaminergic therapeutic approaches to enhance stroke recovery.

Patterns and profiles of methylphenidate use both in children and adults

AIM

The aim of the present study was to characterize patterns of use of methylphenidate (MPH), a prescription stimulant medication recommended in the treatment of attention deficit hyperactivity disorder (ADHD) and of narcolepsy, in France, both in children and adults, over a 3-year period.

METHODS

Using the French General Health Insurance database, limited to two areas covering approximately 4 million individuals, we made up a cohort of incident MPH users between July 2010 and June 2013. Splitting them into distinct age groups (18-24, 25-49 and ≥50 years of age for adults and <6, 6-11 and 12-17 years of age for children), we established the characteristics of these populations at MPH initiation and during follow-up according to the duration of treatment, quantities dispensed and coprescription with central nervous system (CNS) drugs.

RESULTS

We included a cohort of 3534 incident users, involving 30 238 dispensings of MPH, leading to an annual rate of 29 incident users per 100 000 in 2013. Children (66% of new users) were characterized by long-term use of MPH with few comedications. The group of 25-49-year-old patients were dispensed MPH more frequently than other groups, had the highest mean dose and were more often coprescribed other CNS drugs. The ≥50 year-old group was more often coprescribed antidepressants and antiparkinsonian drugs.

CONCLUSIONS

Our pharmacoepidemiological study involving incident MPH users with a large number of characteristics showed different patterns of MPH use among children and adults. The results from the 25-49-year-old group suggested that MPH might be being used for medical conditions other than ADHD or narcolepsy in adults, and that it might be subject to misuse and/or abuse.