Effect of Pharmacological Treatment of Attention-Deficit/Hyperactivity Disorder on Criminality

OBJECTIVE

Criminality rates are higher among persons with attention-deficit/hyperactivity disorder (ADHD), and evidence that medication reduces crime is limited. Medication rates between clinics vary widely even within universal health care systems, partly because of providers' treatment preferences. We used this variation to estimate causal effects of pharmacological treatment of ADHD on 4-year criminal outcomes.

METHOD

We used Norwegian population-level registry data to identify all unique patients aged 10 to 18 years diagnosed with ADHD between 2009 and 2011 (n = 5,624), their use of ADHD medication, and subsequent criminal charges. An instrumental variable design, exploiting variation in provider preference for ADHD medication between clinics, was used to identify causal effects of ADHD medication on crime among patients on the margin of treatment, that is, patients who receive treatment because of their provider's preference.

RESULTS

Criminality was higher in patients with ADHD relative to the general population. Medication preference varied between clinics and strongly affected patients' treatment. Instrumental variable analyses supported a protective effect of pharmacological treatment on violence-related and public-order-related charges with numbers needed to treat of 14 and 8, respectively. There was no evidence for effects on drug-, traffic-, sexual-, or property-related charges.

CONCLUSION

This is the first study to demonstrate causal effects of pharmacological treatment of ADHD on some types of crimes in a population-based natural experiment. Pharmacological treatment of ADHD reduced crime related to impulsive-reactive behavior in patients with ADHD on the margin of treatment. No effects were found on crimes requiring criminal intent, conspiracy, and planning.

STUDY PREREGISTRATION INFORMATION

The ADHD controversy project: Long-term effects of ADHD medication; https://www.isrctn.com/; 11891971.

Variation in attitudes toward diagnosis and medication of ADHD: a survey among clinicians in the Norwegian child and adolescent mental health services

Prevalence and medication rates of ADHD vary geographically, both between and within countries. No absolute cutoff exists between ADHD and normal behavior, making clinician attitudes (leading to local practice cultures) a potential explanation for the observed variation in diagnosis and medication rates. The objective of this study was to describe variation in attitudes toward diagnosis and medication of ADHD among clinicians working in child and adolescent mental health services (CAMHS). We hypothesized that attitudes would vary along a spectrum from "restrictive" to "liberal". We also explored whether differences in attitudes between clinicians were related to professional background and workplace (clinic). A survey in the form of a web-based questionnaire was developed. All CAMHS outpatient clinics in Norway were invited. Potential respondents were all clinicians involved in diagnosing and treating children and adolescents with ADHD. To investigate the existence of attitudes toward diagnosis and medication as latent constructs, we applied confirmatory factor analysis (CFA). We further examined how much of variance in attitudes could be ascribed to profession and clinics by estimating intraclass correlation coefficients. In total, 674 respondents representing 77 (88%) of the clinics participated. We confirmed variation in attitudes with average responses leaning toward the "restrictive" end of the spectrum. CFA supported "attitude toward diagnosis" and "attitude toward medication" as separate, and moderately correlated (r = 0.4) latent variables, representing a scale from restrictive to liberal. Professional background and workplace explained only a small part of variance in these attitudes.

A systematic meta-review of systematic reviews on attention deficit hyperactivity disorder

BACKGROUND

There are now hundreds of systematic reviews on attention deficit hyperactivity disorder (ADHD) of variable quality. To help navigate this literature, we have reviewed systematic reviews on any topic on ADHD.

METHODS

We searched MEDLINE, PubMed, PsycINFO, Cochrane Library, and Web of Science and performed quality assessment according to the Joanna Briggs Institute Manual for Evidence Synthesis. A total of 231 systematic reviews and meta-analyses met the eligibility criteria.

RESULTS

The prevalence of ADHD was 7.2% for children and adolescents and 2.5% for adults, though with major uncertainty due to methodological variation in the existing literature. There is evidence for both biological and social risk factors for ADHD, but this evidence is mostly correlational rather than causal due to confounding and reverse causality. There is strong evidence for the efficacy of pharmacological treatment on symptom reduction in the short-term, particularly for stimulants. However, there is limited evidence for the efficacy of pharmacotherapy in mitigating adverse life trajectories such as educational attainment, employment, substance abuse, injuries, suicides, crime, and comorbid mental and somatic conditions. Pharmacotherapy is linked with side effects like disturbed sleep, reduced appetite, and increased blood pressure, but less is known about potential adverse effects after long-term use. Evidence of the efficacy of nonpharmacological treatments is mixed.

CONCLUSIONS

Despite hundreds of systematic reviews on ADHD, key questions are still unanswered. Evidence gaps remain as to a more accurate prevalence of ADHD, whether documented risk factors are causal, the efficacy of nonpharmacological treatments on any outcomes, and pharmacotherapy in mitigating the adverse outcomes associated with ADHD.

Effect of ADHD medication on risk of injuries: a preference-based instrumental variable analysis

ADHD is associated with an increased risk of injury. Causal evidence for effects of pharmacological treatment on injuries is scarce. We estimated effects of ADHD medication on injuries using variation in provider preference as an instrumental variable (IV). Using Norwegian registry data, we followed 8051 patients who were diagnosed with ADHD aged 5 to 18 between 2009 and 2011 and recorded their ADHD medication and injuries treated in emergency rooms and emergency wards up to 4 years after diagnosis. Persons with ADHD had an increased risk of injuries compared to the general population (RR 1.35; 95% CI: 1.30-1.39), with higher risk in females (RR 1.47; 95% CI: 1.38-1.56) than males (RR 1.23; 95% CI: 1.18-1.28). The between-clinics variation in provider preference for ADHD medication was large and had a considerable impact on patients' treatment status. There was no causal evidence for protective effects of pharmacological treatment on injuries overall for young individuals with ADHD characterized by milder or atypical symptoms. However, there was an apparent effect of pharmacological treatment over time on the risk of injuries treated at emergency wards in this patient group.

Geographical variation in ADHD: do diagnoses reflect symptom levels?

Rates of ADHD diagnosis vary across regions in many countries. However, no prior study has investigated how much within-country geographic variation in ADHD diagnoses is explained by variation in ADHD symptom levels. We examine whether ADHD symptom levels explain variation in ADHD diagnoses among children and adolescents using nationwide survey and register data in Norway. Geographical variation in incidence of ADHD diagnosis was measured using Norwegian registry data from the child and adolescent mental health services for 2011-2016. Geographical variation in ADHD symptom levels in clinics' catchment areas was measured using data from the Norwegian mother, father and child cohort study for 2011-2016 (n = 39,850). Cross-sectional associations between ADHD symptom levels and the incidence of ADHD diagnoses were assessed with fractional response models. Geographical variation in ADHD diagnosis rates is much larger than what can be explained by geographical variation in ADHD symptoms levels. Treatment in the Norwegian child and adolescent mental health services is free, universally available upon referral, and practically without competition from the private sector. Factors beyond health care access and unequal symptom levels seem responsible for the geographical variation in ADHD diagnosis.

Preference-based instrumental variables in health research rely on important and underreported assumptions: a systematic review

OBJECTIVE

Preference-based instrumental variables (PP IV) designs can identify causal effects when patients receive treatment due to variation in providers' treatment preference. We offer a systematic review and methodological assessment of PP IV applications in health research.

STUDY DESIGN AND SETTING

We included studies that applied PP IV for evaluation of any treatment in any population in health research (PROSPERO: CRD42020165014). We searched within four databases (Medline, Web of Science, ScienceDirect, SpringerLink) and four journals (including full-text and title and abstract sources) between January 1, 1998, and March 5, 2020. We extracted data on areas of applications and methodology, including assumptions using Swanson and Hernan's (2013) guideline.

RESULTS

We included 185 of 1087 identified studies. The use of PP IV has increased, being predominantly used for treatment effects in cancer, cardiovascular disease, and mental health. The most common PP IV was treatment variation at the facility-level, followed by physician- and regional-level. Only 12 percent of applications report the four main assumptions for PP IV. Selection on treatment may be a potential issue in 46 percent of studies.

CONCLUSION

The assumptions of PP IV are not sufficiently reported in existing work. PP IV-studies should use reporting guidelines.

Causal modelling of variation in clinical practice and long-term outcomes of ADHD using Norwegian registry data: the ADHD controversy project

INTRODUCTION

Attention-deficit/hyperactivity disorder (ADHD) is among the most common mental disorders in children and adolescents, and it is a strong risk factor for several adverse psychosocial outcomes over the lifespan. There are large between-country and within-country variations in diagnosis and medication rates. Due to ethical and practical considerations, a few studies have examined the effects of receiving a diagnosis, and there is a lack of research on effects of medication on long-term outcomes.Our project has four aims organised in four work packages: (WP1) To examine the prognosis of ADHD (with and without medication) compared with patients with other psychiatric diagnoses, patients in contact with public sector child and adolescent psychiatric outpatient clinics (without diagnosis) and the general population; (WP2) Examine within-country variation in ADHD diagnoses and medication rates by clinics' catchment area; and(WP3) Identify causal effects of being diagnosed with ADHD and (WP4) ADHD medication on long-term outcomes.

METHOD AND ANALYSIS

Our project links several nationwide Norwegian registries. The patient sample is all persons aged 5-18 years that were in contact with public sector child and adolescent psychiatric outpatient clinics in 2009-2011. Our comparative analysis of prognosis will be based on survival analysis and mixed-effects models. Our analysis of variation will apply mixed-effects models and generalised linear models. We have two identification strategies for the effect of being diagnosed with ADHD and of receiving medication on long-term outcomes. Both strategies rely on using preference-based instrumental variables, which in our project are based on provider preferences for ADHD diagnosis and medication.

ETHICS AND DISSEMINATION

The project is approved by the Regional Ethics Committee, Norway (REC number 2017/2150/REC south-east D). All papers will be published in open-access journals and results will be presented in national and international conferences.

TRIAL REGISTRATION NUMBERS

ISRCTN11573246 and ISRCTN11891971.