Use of methylphenidate among children in Iceland 1989-2006

Neðst á síðunni er hægt að nálgast greinina í heild sinni með því að smella á hlekkinn View/OpenSTUDY OBJECTIVE: To determine the prevalence of methylphenidate use among children in Iceland and show utilization trends from 1989 to 2006. Patterns of use were analyzed by sex, age and region of habitation, short-acting vs. long-acting formulations and presciber's specialty. MATERIALS AND METHODS: A descriptive observational study. Data was retrieved from the nationwide Register on Prescribed Drugs in Iceland and the Icelandic Directorate of Health surveillance system on prescribed methylphenidate. The study population encompassed the total pediatric population (0-18 year-olds) in Iceland during the study period. Total, sex-, age, and region-specific yearly prevalence rates were computed. Specific prevalence rates of short-acting and long-acting methylphenidate use were compared. Prescribed volume and number of prescriptions were analyzed in relation to specialty of prescriber. Prevalence ( per thousand) was defined as the number of children per 1,000 children in the population who received at least one methylphenidate prescription in the given year. RESULTS: The total prevalence of methylphenidate use among children (0-18) in Iceland was 0.2 per thousand in 1989 and 25.1 per thousand in 2006. Overall use was three times more common among boys than girls. Prevalence was highest at age 10, 77.4 per thousand among boys and 24.3 per thousand among girls. A variance in use between regions was detected. Prevalence of short-acting methylphenidate use decreased from 2003 (18.7 per thousand) to 2006 (6.8 per thousand), while prevalence of long-acting medication increased from 14.4 per thousand to 24.6 per thousand. In 2006 pediatricians were the most common prescribers of methylphenidate to children in Iceland, accounting for 41% of prescriptions. CONCLUSION: Use of methylphenidate among children in Iceland increased considerably from 1989 to 2004, when a plateau seems to have been reached. In accordance with the trend in many Western countries, a rise in use of long-acting drugs was detected concurrently with a steep decrease in use of short-acting drugs. Compared to utilization rates in Europe, prevalence of methylphenidate use among children in Iceland is high.Inngangur: Markmið rannsóknarinnar var að greina algengi og þróun metýlfenídatnotkunar meðal barna á Íslandi frá árinu 1989 til 2006. Mynstur notkunar var greint eftir kyni, aldri og búsetu sjúklings, verkunartíma lyfs og sérgrein læknis sem ávísaði lyfinu. Efniviður og aðferðir: Lýsandi áhorfsrannsókn sem byggir á gögnum úr lyfjagagnagrunni Landlæknisembættisins, tölfræðigrunni Tryggingastofnunar ríkisins (TR) og gögnum Landlæknisembættisins um lyf undir sérstöku eftirliti. Þýði rannsóknar voru íslensk börn á aldrinum 0-18 ára á rannsóknartímabili. Gögn um lyfjanotkun voru greind með tilliti til kyns, aldurs og búsetu sjúklings, verkunartíma lyfs (stuttverkandi, langverkandi áhrif) og sérgrein læknis. Algengi metýlfenídatnotkunar (%0) var skilgreint sem fjöldi einstaklinga á hverja 1000 íbúa sem innleysti eina eða fleiri lyfjaávísun á metýlfenídat ár hvert. Niðurstöður: Algengi metýlfenídatnotkunar meðal barna (0-18 ára) á Íslandi hækkaði úr 0,2%0 árið 1989 í 25,1 %0 árið 2006. Notkun var að jafnaði þrisvar sinnum algengari meðal drengja en stúlkna. Algengið var árið 2006 hæst við 10 ára aldur (drengir 77,4 %0, stúlkur 24,3%0). Meðalársalgengi metýlfenídatnotkunar 2004 til 2006 var hæst meðal drengja á Suðurnesjum (44,80%0) og stúlkna á Norðurlandi vestra (17,06%0) en lægst á Vestfjörðum (drengir 23,44%0, stúlkur 8,06%0). Notkun stuttverkandi metýlfenídats minnkaði frá árinu 2003 (18,7%0) til ársins 2006 (6,8%0) en notkun langverkandi metýlfenídats jókst úr 14,4%0 í 24,6%0. Barnalæknar ávísuðu oftast lækna metýlfenídatlyfjum, 41% af heildarfjölda ávísana árið 2006. Ályktanir: Notkun metýlfenídats meðal íslenskra barna jókst töluvert frá upphafi rannsóknartímabils fram til ársins 2004 þegar ákveðnu jafnvægi virðist hafa verið náð. Líkt og víða hefur notkun langverkandi lyfja aukist á kostnað stuttverkandi lyfjaforms. Samanborið við önnur Evrópulönd er notkun metýlfenídats á Íslandi mikil

Children's relative age in class and use of medication for ADHD: a Danish Nationwide Study

Background: Previous studies from North America and Iceland have shown that the youngest children within a grade are up to twice as likely to be diagnosed and treated for attention-deficit/hyperactivity disorder (ADHD) compared with their older classmates. We aimed to investigate whether younger age in class is associated with an increased probability of being prescribed medication for ADHD among school-aged children in Denmark. Methods: We followed all Danish children between 2000 and 2012 from 1st through 6th grade (7–12 years). Among children who started school on their age-assigned grade level, we estimated the prevalence proportion ratio (PPR) of receiving ADHD medication between the youngest children in class (born in October–December) and the oldest in class (born in January–March), specified by grade level, calendar year and gender. As a sensitivity analysis, we added children not on their age-assigned grade level to the main calculations. Results: We identified 932,032 eligible children for the main analysis, of whom 17.3% were among the youngest and 26.5% among the oldest in class. In total, 1.2% eligible children filled at least one prescription for ADHD medication in 2000–2012. The average PPR over the study period was 1.08 (95% CI, 1.04–1.12) and remained stable across subgroups and sensitivity analyses. Overall, 40% of children born October–December had entered school a year after their age-assigned grade level. Conclusions: Contrary to previous study results, we observed almost no relative age effect on medication use for ADHD among children in Denmark. We postulate that this may be due to the high proportion of relatively young children held back by 1 year in the Danish school system and/or a generally low prevalence of ADHD medication use in the country

Prevalence of psychotropic drug use among elderly Icelanders living at home

Neðst á síðunni er hægt að nálgast greinina í heild sinni með því að smella á hlekkinn View/OpenOBJECTIVE: To evaluate the prevalence of psychotropic drug use among home-dwelling elderly Icelanders in the year 2006. MATERIALS AND METHODS: A population-based drug utilization study using the Icelandic Medicines Registry. The study group consisted of Icelanders, seventy years and older living at home (8% of total population). Prevalence of antidepressant, neuroleptic, anxiolytic and hypnotic use (ATC-groups N06A, N05A, N05B, N05C) was defined as the dispension per 100 individuals of one or more prescriptions for these drugs within the year 2006. For cross-national comparison we used data for 70-74 year olds in the Danish Registry of Medicinal Product Statistics. RESULTS: One third of all dispensed prescriptions in Iceland in 2006 were for people aged 70 years and older, and one fourth were for psychotropics. Elderly women were more likely than men to use psychotropics (RR=1.40 95% CI: 1.37-1.43). The prevalence of psychotropic use was 65.5% for women and 46.8% for men. Anxiolytics and hypnotics (N05B or N05C) were the most frequently used psychotropics, with a prevalence of 58.5% for women and 40.3% for men. Antidepressants were used by 28.8 % of women and 18.4 % of men. Neuroleptics were used by 5%. By comparing 70-74 years old Icelanders and Danes, the Icelanders were 1.5 to 2.5 times more likely to receive any psychotropics drug in 2006. CONCLUSION: Use of psychotropics, especially anxiolytics and hypnotics, is common among elderly Icelanders. Comparing information for 70 to 74 year olds with Danes of same age, the prescribing of psychotropics is more frequent in Iceland.Markmið: Að meta algengi geðlyfjanotkunar aldraðra sem bjuggu utan stofnana árið 2006. Efniviður og aðferðir: Lýsandi áhorfsrannsókn sem byggði á gögnum úr lyfjagagnagrunni Landlæknisembættisins. Þýðið var Íslendingar 70 ára og eldri sem bjuggu utan stofnana (8,6% af heildarmannfjölda). Algengi þunglyndis-, geðrofs-, kvíðastillandi- og svefnlyfjanotkunar (ATC-flokkar N06A, N05A, N05B, N05C) var skilgreint sem fjöldi einstaklinga á hverja 100 íbúa sem leysti út eina eða fleiri lyfjaávísun á tiltekin lyf árið 2006. Niðurstöður voru bornar saman við upplýsingar úr lyfjagagnagrunni um geðlyfjanotkun Dana á aldrinum 70 til 74 ára. Niðurstöður: Einstaklingar 70 ára og eldri leystu út þriðjung allra lyfjaávísana á Íslandi árið 2006, þar af var fjórðungur á geðlyf. Eldri konur voru líklegri en karlar til að nota geðlyf (RR=1,40 95% CI: 1,37-1,43). Algengi geðlyfjanotkunar í þýðinu var 65,5% fyrir konur og 46,8% fyrir karla. Algengust var notkun kvíðastillandi lyfja og svefnlyfja (N05B eða N05C), 58,5% meðal kvenna og 40,3% meðal karla. Algengi þunglyndislyfjanotkunar var 28,8% meðal kvenna og 18,4% meðal karla. Um 5% þýðisins notaði geðrofslyf. Algengi geðlyfjanotkunar meðal 70-74 ára var 1,5 til 2,5 falt hærra á Íslandi en Danmörku. Ályktun: Geðlyfjanotkun eldri Íslendinga er almenn, einkum í flokkum kvíðastillandi- og svefnlyfja. Samanborið við upplýsingar úr dönskum lyfjagagnagrunni fyrir aldurshópinn 70-74 ára er ávísun á geðlyf algengari á Íslandi

Pregnancy-Induced Hypertensive Disorders before and after a National Economic Collapse: A Population Based Cohort Study.

To access publisher's full text version of this article, please click on the hyperlink in Additional Links field or click on the hyperlink at the top of the page marked Files. This article is open access.Data on the potential influence of macroeconomic recessions on maternal diseases during pregnancy are scarce. We aimed to assess potential change in prevalence of pregnancy-induced hypertensive disorders (preeclampsia and gestational hypertension) during the first years of the major national economic recession in Iceland, which started abruptly in October 2008.Women whose pregnancies resulted in live singleton births in Iceland in 2005-2012 constituted the study population (N = 35,211). Data on pregnancy-induced hypertensive disorders were obtained from the Icelandic Medical Birth Register and use of antihypertensive drugs during pregnancy, including β-blockers and calcium channel blockers, from the Icelandic Medicines Register. With the pre-collapse period as reference, we used logistic regression analysis to assess change in pregnancy-induced hypertensive disorders and use of antihypertensives during the first four years after the economic collapse, adjusting for demographic and pregnancy characteristics, taking aggregate economic indicators into account. Compared with the pre-collapse period, we observed an increased prevalence of gestational hypertension in the first year following the economic collapse (2.4% vs. 3.9%; adjusted odds ratio [aOR] 1.47; 95 percent confidence interval [95%CI] 1.13-1.91) but not in the subsequent years. The association disappeared completely when we adjusted for aggregate unemployment rate (aOR 1.04; 95% CI 0.74-1.47). Similarly, there was an increase in prescription fills of β-blockers in the first year following the collapse (1.9% vs.3.1%; aOR 1.43; 95% CI 1.07-1.90), which disappeared after adjusting for aggregate unemployment rate (aOR 1.05; 95% CI 0.72-1.54). No changes were observed for preeclampsia or use of calcium channel blockers between the pre- and post-collapse periods.Our data suggest a transient increased risk of gestational hypertension and use of β-blockers among pregnant women in Iceland in the first and most severe year of the national economic recession.RANNIS/12045202

Sense of security during COVID-19 isolation improved with better health literacy - A cross-sectional study

Funding Information: This work was supported by the University of Iceland Research Fund , the Icelandic Nurses’ Association Research Fund and Landspitali University Hospital Science Fund ( A-2022-051 ). Publisher Copyright: © 2023 The AuthorsOBJECTIVE: To assess sense of security, health literacy, and the association between sense of security and health literacy during COVID-19 self-isolation. METHODS: In this cross-sectional survey all adults who caught COVID-19 from the onset of the pandemic until June 2020 in Iceland and received surveillance from a special COVID-19 outpatient clinic, were eligible. Participants retrospectively answered the Sense of Security in Care - Patients' Evaluation and the European Health Literacy Survey Questionnaire. Data were analysed with parametric and non-parametric tests. RESULTS: Participants' (N = 937, 57% female, median age 49 (IQR=23)) sense of security during isolation was Med 5.5 (IQR=1) and 90% had sufficient health literacy. The proposed regression model (R2 =.132) indicated that those with sufficient health literacy had, on average, higher sense of security than those with inadequate health literacy. CONCLUSION: Sense of security was high among individuals who received surveillance from an outpatient clinic during isolation and was associated with health literacy. The high health literacy rate may be an indication of a high COVID-19 specific health literacy rather than general health literacy. PRACTICE IMPLICATIONS: Healthcare professionals can improve the sense of security of patients through measures to improve their health literacy, including their navigation health literacy, by practising good communication, and providing effective patient education.Peer reviewe

A population-based study of stimulant drug treatment of ADHD and academic progress in children.

To access publisher's full text version of this article. Please click on the hyperlink in Additional Links field.We evaluated the hypothesis that later start of stimulant treatment of attention-deficit/hyperactivity disorder adversely affects academic progress in mathematics and language arts among 9- to 12-year-old children. We linked nationwide data from the Icelandic Medicines Registry and the Database of National Scholastic Examinations. The study population comprised 11,872 children born in 1994-1996 who took standardized tests in both fourth and seventh grade. We estimated the probability of academic decline (drop of ≥ 5.0 percentile points) according to drug exposure and timing of treatment start between examinations. To limit confounding by indication, we concentrated on children who started treatment either early or later, but at some point between fourth-grade and seventh-grade standardized tests. In contrast with nonmedicated children, children starting stimulant treatment between their fourth- and seventh-grade tests were more likely to decline in test performance. The crude probability of academic decline was 72.9% in mathematics and 42.9% in language arts for children with a treatment start 25 to 36 months after the fourth-grade test. Compared with those starting treatment earlier (≤ 12 months after tests), the multivariable adjusted risk ratio (RR) for decline was 1.7 (95% confidence interval [CI]: 1.2-2.4) in mathematics and 1.1 (95% CI: 0.7-1.8) in language arts. The adjusted RR of mathematics decline with later treatment was higher among girls (RR, 2.7; 95% CI: 1.2-6.0) than boys (RR, 1.4; 95% CI: 0.9-2.0). Later start of stimulant drug treatment of attention-deficit/hyperactivity disorder is associated with academic decline in mathematicsPfizer Novartis University of Iceland Icelandic Centre for Research (RANNIS

Confronting the unknown—Nursing surveillance of COVID-19-infected patients through remote telephone calls and in an on-site urgent clinic

Funding Information: University of Iceland Research Fund. We wish to thank Runólfur Pálsson, MD, Professor and Director of Internal Medicine and Rehabilitation Services, Sigríður Gunnarsdóttir, Chief Nursing Officer for support in conducting this study, Drífa Katrín Guðmundsdóttir Blöndal and Stefanía Bergsdóttir for transcribing the interviews and giving an insightful view on the data analysis and Ásvaldur Kristjánsson for assistance with conducting the focus group interviews. Publisher Copyright: © 2022 The Authors. Journal of Advanced Nursing published by John Wiley & Sons Ltd.Aim: To describe nursing surveillance of coronavirus disease 2019 (COVID-19)-infected patients through remote telephone calls and in an on-site urgent clinic during the first wave of the pandemic as experienced by nurses providing the care. Design: Qualitative descriptive study. Methods: Data were collected through seven semi-structured, audio-recorded, focus group interviews with 24 nurses. Interviews were conducted in May and June 2020, transcribed and analysed using deductive and inductive content analysis into an overarching category, main categories and subcategories. Reporting followed the COREQ guidelines. Results: Nurses relied on intensive listening when assessing and caring for COVID-19-infected patients. They realized that the patients had complex needs for nursing and healthcare which was beyond the scope of a tentatively prescribed assessment scheme. They designed their care to ensure holistic care, reflected in the overarching category, ‘Confronting an unfamiliar health condition in unprecedented circumstances’ and the categories: ‘Digging into the unknown’ and ‘Ensuring holistic nursing care’. The category ‘Contributing to averting catastrophe’ reflects the wealth of knowledge, support and experience that the nurses used to independently deliver care, albeit in interdisciplinary collaboration, working to their greatest potential. They were proud of the significance of their work. Conclusion: Novel nursing surveillance through remote telephone calls and in an on-site urgent care clinic delivered to COVID-19 patients self-managing at home resulted in holistic nursing care during the first wave of the pandemic. This has relevance for professionalism in nursing. Impact: Findings give a unique insight into nursing surveillance of COVID-19-infected patients provided through telephone calls and in on-site urgent care clinics. The potential of intensive listening as conducted in the study suggests that it may be feasible to assess and holistically take care of COVID-19-infected patients, and other patient groups as well, with this form of healthcare. This has relevance for healthcare beyond crisis management during pandemics. Patient or Public Contribution: There was no patient or public contribution as the study only concerned the providers of the service, i.e. the nurses themselves.Peer reviewe

Geðlyfjanotkun meðal barna: Samanburður á notkun ADHD lyfja á Norðurlöndunum og áhrif lyfjameðferðar við ADHD á námsárangur

Abstract Attention-deficit hyperactivity disorder (ADHD) is a neurodevelopmental disorder affecting 5-10% of school-aged children. Drug treatment for ADHD with stimulants is now widely used as a therapeutic option in the US and increasingly in Europe. Nevertheless, the increasing use of ADHD drugs is debated, chiefly because of concerns of over-use, addiction and uncertainty of the long-term outcomes of treatment. Although research in pediatric psychopharmacology has expanded during the past decade, utilization studies have typically rested on limited data sources. Thus, the evidence base for prevalence of use and treatment safety, as well as long-term risks and effectiveness of many psychotropic agents for children remains fragmented. The long-term effects of stimulant treatment are largely unknown and evidence about their effect on academic progress among children with ADHD is limited. Our studies are based on the unique setting in Iceland, the nationwide prescription drug registries now available in all Nordic countries and the rare opportunity of record linkage to national scholastic examinations in Iceland. We aimed to investigate patterns of psychotropic drugs use among the total pediatric population in Iceland, to compare ADHD drug use among all Nordic countries and, finally, to address whether children’s academic progress is affected by the initiation of stimulant treatment for ADHD. In Study I we found a markedly high prevalence between 2003 and 2007 of psychotropic drug use among children in Iceland (48.7 per 1000 in 2007). Stimulants and antidepressants were the two most commonly used psychotropic drugs in 2007, respectively with a prevalence of 28.4 and 23.4 per 1000 children. A statistically significant trend of declining prevalence and incidence of antidepressant use occurred during the study period, while prevalence increased for use of stimulants and antipsychotics. Out of 21,986 psychotropic drugs dispensed in 2007, 25.4% were used off-label for children. In Study II we compared national use in 2007 of ADHD drugs (stimulants and atomoxetine) between all five Nordic countries, covering in total almost 25 million individuals. We found a significant difference in the extent of utilization between the countries. The prevalence of use varied from a low 1.2 per 1000 inhabitants in Finland, to a high 12.5 per 1000 in Iceland. Children aged 7 to 15 years were in 2007 almost five times more likely in Iceland, than in Sweden to have been dispensed an ADHD drug. Prevalence among Nordic boys (age 7-15) was 4.3-fold the prevalence among Nordic girls, while among adults (age 21+) women were almost as likely as men to use ADHD drugs. In all five Nordic countries methylphenidate was the most commonly used ADHD drug, accounting for over 80% of the use in 2007. It was also the only ADHD drug with a valid marketing authorization and reimbursed in every Nordic county. In study III we investigated the extent to which academic progress among 9- to 12-year old children is related to initiation of stimulant treatment, covering 11,872 children who took standardized tests in mathematics and language arts. In contrast with non-medicated children in the general population, children starting stimulant treatment between 4th and 7th grade tests presented with an overall academic decline. Compared with those starting stimulant treatment earlier (≤12 months after 4th grade test), children with later treatment start (25-36 months after 4th grade test) were 1.7-fold more likely to decline academically in mathematics and 1.1-fold more likely to decline in language arts. The adjusted risk ratio of mathematics decline with later treatment was higher among girls (RR, 2.7), than boys (RR, 1.4). In conclusion, based on nationwide registry data from the Nordic countries our results indicate (I) a markedly high use of psychotropic drugs, especially of stimulants and antidepressants, among children in Iceland and (II) a considerable variation in use of ADHD stimulant drugs in the Nordic countries. Furthermore, our results indicate (III) that later start of stimulant drug treatment for ADHD is associated with academic decline, particularly in mathematics. Keywords: psychotropic drug use, stimulant drug treatment, ADHD, academic progress, nationwide registry data, population-basedÁgrip Enn vantar vísindalegan grunn um útbreiðslu geðlyfjanotkunar, meðferðaröryggi og áhrif ýmissa geðlyfja fyrir börn, þrátt fyrir aukna þekkingu um notkun og virkni geðlyfja fyrir börn síðastliðinn áratug. Athyglisbrestur og ofvirkni (ADHD) er taugaþroskaröskun sem 5-10% barna á skólaaldri glíma við. Örvandi lyfjameðferð er útbreitt meðferðarform fyrir börn með ADHD í Bandaríkjunum og í auknum mæli í Evrópulöndum. Vaxandi notkun ADHD lyfja er umdeild í ljósi mögulegrar of- og misnotkunar og vegna óvissu um langtímaáhrif lyfjameðferðar. Enn er lítið vitað um langtímaáhrif örvandi lyfjameðferðar og þekkingu vantar um áhrif meðferðar á námsárangur barna með ADHD. Niðurstöður okkar byggja á einstökum rannsóknaraðstæðum á Íslandi, sem felast í fágætu tækifæri til samtengingar gagna á landsvísu um lyfjanotkun og námsárangur barna á samræmdum prófum, ásamt lýðgrunduðum lyfjagagnagrunnum á öllum Norðurlöndunum. Markmið okkar var að (I) lýsa mynstri geðlyfjanotkunar meðal allra barna á Íslandi, (II) bera saman tíðni notkunar ADHD lyfja á Norðurlöndunum og (III) kanna tengsl námsárangurs og örvandi lyfjameðferðar hjá börnum með ADHD. Í fyrstu rannsókn okkar lýstum við mynstri geðlyfjanotkunar meðal íslenskra barna. Niðurstöður sýndu að á árunum 2003 til 2007 var algengi geðlyfjanotkunar meðal íslenskra barna hlutfallslega hátt (48,7 á hver 1000 börn 2007). Algengust var notkun örvandi lyfja (28,4 á hver 1000 börn 2007) og þunglyndislyfja (23,4 á hver 1000 börn 2007). Bæði algengi og nýgengi þunglyndislyfjanotkunar lækkaði marktækt á rannsóknartímabilinu en algengi notkunar örvandi lyfja og geðrofslyfja jókst. Meðal þeirra 21.986 geðlyfja sem voru útleyst fyrir börn árið 2007 var rúmlega fjórðungur (25,4%) án ábendingar fyrir börn. Í annarri rannsókn okkar bárum við saman notkun ADHD lyfja (örvandi lyf og atomoxetín) árið 2007 meðal nærri 25 milljóna íbúa Norðurlandanna. Marktækur munur fannst á lyfjanotkun milli landanna fimm. Lægst var algengið í Finnlandi (1,2 á hverja 1000 íbúa) en hæst á Íslandi (12,5 á hverja 1000 íbúa). Árið 2007 voru íslensk börn (7-15 ára) nærri fimm sinnum líklegri en sænsk börn til að fá útleyst ADHD lyf. Algengi notkunar var rúmlega fjórfalt hærra hjá norrænum drengjum (7-15 ára) en norrænum stúlkum. Meðal fullorðinna (21 árs og eldri) var notkun lyfjanna nær jöfn. Metýlfenídat var mest notaða ADHD lyfið í hverju landi og náði yfir rúmlega 80% notkunar árið 2007. Jafnframt var það eina lyfið með markaðsleyfi og endurgreitt á öllum fimm Norðurlöndum. Þriðja rannsókn okkar var um tengsl upphafs örvandi lyfjameðferðar og námsframvindu hjá 9 til 12 ára börnum. Rannsóknin náði til barna sem höfðu tekið samræmd próf í stærðfræði og íslensku bæði í 4. og 7. bekk, alls 11.872 börn. Námsárangur barna úr almennu þýði stóð í stað milli 4. og 7. bekkjarprófa á meðan árangur barna sem fékk lyfjameðferð við ADHD versnaði almennt. Áhættan á versnun í námi var aukin meðal barna sem hófu lyfjameðferð seint (25-36 mánuðum eftir 4. bekkjarpróf) samanborið við þau börn sem hófu lyfjameðferð fyrr (≤12 mánuðum eftir 4. bekkjarpróf). Áhættuhlutfallið var 1,7 í stærðfræði og 1,1 í íslensku. Stelpum sem hófu lyfjameðferð seint var hættara við versnun í stærðfræði (áhættuhlutfall 2,7) en strákum (áhættuhlutfall 1,4). Niðurstöður okkar, sem byggja á lýðgrunduðum upplýsingum úr miðlægum gagnagrunnum á Norðurlöndunum, benda til þess (I) að notkun geðlyfja, einkum örvandi- og þunglyndislyfja, sé algeng meðal íslenskra barna og (II) að töluverður munur sé á algengi örvandi lyfjanotkunar við ADHD milli Norðurlandanna. Ennfremur benda niðurstöður til þess (III) að börnum með ADHD sem hefja lyfjameðferð seint sé hættara við að hraka í námi en þeim sem hefja meðferð fyrr, sér í lagi í stærðfræði. Lykilorð: geðlyfjanokun, örvandi lyfjameðferð, ADHD, námsárangur, miðlæg gögn á landsvísu, lýðgrunduð rannsóknRannsóknarmiðstöð Íslands, RANNÍS, styrkti verkefnið. Doktorsefnið hlaut einnig styrki úr Rannsóknarsjóði Háskóla Íslands (Doktorsstyrkur, Aðstoðarmannasjóðsstyrkur, Verkefnastyrkur og Ferðastyrkir)