Concept: Attention-Deficit Hyperactivity Disorder (ADHD)

Introduction

This concept describes the research methods used at the Manitoba Centre for Health Policy (MCHP) over time to define Attention-Deficit Hyperactivity Disorder (ADHD), including the specific ICD codes, prescription drugs and additional conditions that are involved. Findings from MCHP research are listed and described, and links to specific report information are provided.

Attention-Deficit Hyperactivity Disorder (ADHD) can generally be described as a neurobehavioral developmental disorder that is characterized by inattention, hyperactivity, and impulsivity. The disorder is often identified during school ages and symptoms may continue into adulthood. ADHD occurs twice as commonly in boys as in girls (American Psychiatric Association, 2000).

Data Sources

In the following algorithms, the following data sources are used to define ADHD:


• Hospital Abstracts data;
  
• Medical Services (Physician Claims) data; and
  
• Drug Program Information Network (DPIN) data.

Research Definitions and Algorithms

At MCHP, the following research projects have investigated ADHD. Over time, different definitions and algorithms have been used, as described in the following sections.

1. Martens et al. (2004)

In the Patterns of Regional Mental Illness Disorder Diagnoses and Service Use in Manitoba: A Population-Based Study deliverable by Martens et. al (2004), they defined ADD/ADHD as either:


• the presence of ICD-9-CM code 314 (hyperkinetic syndrome) in the Medical Services/Physician Claims data, the Hospital Discharge Abstracts data, or in the Mental Health Management Information System (MHMIS) data, OR
  
• a prescription for a psychostimulant (Cylert, Desoxyn, Dexedrine, Dopram, Ritalin, PMS-Methylphenidate, Vivarin) over the last year of the study.

Additional conditions that were considered included:


• Those individuals that had an ICD-9-CM diagnosis of 312 (conduct disorder) with a prescription for a psychostimulant were considered ADHD with a comorbid condition.
  
• Those individuals with an ICD-9-CM diagnosis code of 347 (catalepsy and narcolepsy) with a prescription for a psychostimulant, but no 314 diagnosis, were removed.
  
• Only individuals aged 4-18 years at the end of 2001/02 were included and ADD/ADHD was measured as a percent of the population for individuals 4-18 years of age.

2. Yallop (2007)

In her thesis, Rates of diagnosis and treatment of Attention-Deficit/Hyperactive Disorder in Manitoba children: Considering the socioeconomic gradient, Yallop, L. (2007), defined ADHD using the following conditions:


• one or more hospitalizations with a diagnosis of hyperkinetic syndrome of childhood (ICD-9-CM code 314) or hyperkinetic disorders (ICD-10 code F90); OR
  
• one or more physician visits with a diagnosis of hyperkinetic syndrome of childhood (ICD-9-CM code 314); OR
  
• two or more prescriptions for a psychostimulant (including Ritalin, Dopram, Vivarin, or Dexedrine) and no diagnosis for conduct disorder, narcolepsy or cataplexy.

The ICD codes used to identify sleep disorders included:


• ICD-9-CM code 347 OR ICD-10 code G47

NOTE: While other forms of treatment for ADHD, such as behavior therapy, are also employed by some Manitoba health practitioners (e.g. psychiatrists and psychologists), this study only considered treatment with respect to psychostimulant use. This decision was based on the lack of comprehensiveness of information on other treatment types as well as the pervasiveness of psychotropic treatment for ADHD.

Additional diagnoses were determined using the following definitions:


• the ICD codes used to identify learning disabilities, included:
  
  
  • ICD-9-CM code 315 (specific delays in development) and ICD-9-CM codes 317-319 (mental retardation); OR
    
  • ICD-10 codes F80-F83 and F88-F89 (disorders of psychological development) and ICD-10 codes F70-F79 (mental retardation).
  
  
• the ICD codes used to identify behaviour disturbances, included:
  
  
  • ICD-9-CM code 312 (disturbance of conduct, not elsewhere classified) and 313 (disturbance of emotions specific to childhood and adolescence); OR
    
  • ICD-10 codes F91-F94 and F98 (conduct disorders, mixed disorders of conduct and emotions, emotional disorders with onset specific to childhood, disorders of social functioning with onset specific to childhood and adolescence, other behavioral and emotional disorders with onset usually occurring in childhood and adolescence).

3. Brownell et al. (2008)

In the report Manitoba Child Health Atlas Update, Brownell et al. (2008), children aged 5 to 19 years of age were defined as having an ADHD diagnosis if they had any of the following conditions:


• one or more hospitalizations with a diagnosis of hyperkinetic syndrome of childhood (ICD-9-CM code 314.xx or ICD-10-CA code F90) in one year; OR
  
• one or more physician visits with a diagnosis of hyperkinetic syndrome of childhood (ICD-9-CM code 314) in one year; OR
  
• two or more prescriptions for a psychostimulant medication within one fiscal year without a corresponding diagnosis of conduct disorder (ICD-9-CM code 312.xx or ICD-10-CA code F91-F94) or narcolepsy (ICD-9-CM code 347 or ICD-10-CA code G47) in one year; OR
  
• one prescription for a psychostimulant in the fiscal year and a diagnosis of hyperkinetic syndrome of childhood in the previous three years.

See the Psychostimulant Codes.pdf for a list of psychostimulants used to identify ADHD in the Child Health Atlas Update (2008).

4. Martens et al. (2010), Chartier et al. (2012, 2015, 2016, 2018), Brownell et al.(2012, 2015, 2018, 2020)

In the following deliverables, the prevalence of ADHD in children was investigated:


• Profile of Metis Health Status and Healthcare Utilization in Manitoba: A Population-Based Study by Martens et al. (2010);
  
• Health and Healthcare Utilization of Francophones in Manitoba by Chartier et al. (2012);
  
• How Are Manitoba's Children Doing? by Brownell et al. (2012);
  
• The Educational Outcomes of Children in Care in Manitoba by Brownell et al. (2015);
  
• Care of Manitobans Living with Chronic Kidney Disease by Chartier et al. (2015);
  
• The Mental Health of Manitoba's Children by Chartier et al. (2016); and
  
• The PAX Program in Manitoba: A Population-Based Analysis of Children's Outcomes by Brownell et al. (2018)
  
• The Overlap Between the Child Welfare and Youth Criminal Justice Systems: Documenting "Cross-Over Kids" by Brownell et al. (2020)
  
  
• And, in the deliverable, Mental Illness Among Adult Manitobans by Chartier et al. (2018) they looked at adults and not children.

Algorithm Definition

In all of the research listed above, ADHD was defined using the following algorithm:


• one or more hospitalizations with a diagnosis of hyperkinetic syndrome (ICD-9-CM code 314 or ICD-10-CA code F90); OR
  
• one or more physician visits with a diagnosis of hyperkinetic syndrome (ICD-9-CM code 314); OR
  
• two or more prescriptions for ADHD drugs without a diagnosis of:
  
  • conduct disorder (ICD-9-CM code 312 or ICD-10-CA codes F63, F91, F92); OR
    
  • disturbance of emotions (ICD-9-CM code 313 or ICD-10-CA codes F93, F94); OR
    
  • cataplexy/narcolepsy (ICD-9-CM code 347 or ICD-10-CA code G47.4); OR
• one prescription for ADHD drugs in one year AND a diagnosis of hyperkinetic syndrome in the previous three years.
  
  NOTE: In most of the defined diagnoses / conditions, the time frame was restricted to within a one year period. In Chartier et al. (2015), this time frame was extended to five years for all mental disorders.

Age restrictions


• In Martens et al. (2010) and Chartier et al. (2012) children were defined as 5-19 years of age.
  
• In Brownell et al. (2012, 2015) and Chartier et al. (2016), children were defined as 6-19 years of age.
  
• In Chartier et al. (2015), children were defined as 6-17 years of age.
  
• In Brownell et al. (2018), the definition is restricted to children ages 3 and older.

Medication Lists

The lists of ADHD medications used in these reports varies:


• In Martens et al. (2010), ADHD medications were identified by:
  
  • the ATC code N06BA; or
    
  • the generic product name of METHYLPHENIDATE, DEXTROAMPHETAMINE, DEXEDRINE, PEMOLINE, or MODAFINIL; or
    
  • the English trade name of CYLERT, DESOXYN, DEXEDRINE, DOPRAM, RITALIN, PMS-METHYL, VIVARIN, RIFENIDATE, ALERTEC, ADDERALL XR, BIPHENTIN, or CONCERTA.
• In Brownell et al. (2012), the list is based on the latest ATC codes and Drug Identification Numbers (DINs) available for ADHD medications - ADHD medication list in Brownell et al. (2012).
  
• In Chartier et al. (2018), the same list was used as Brownell et al. (2012).
  
• In Brownell et al. (2018), ADHD medications were identified by:
  • the ATC code N06BA; or
    
  • the generic product name of DEXTROAMPHETAMINE or AMPHETAMINE.

Research Findings

The following provides a brief description of how ADHD was investigated in several MCHP research projects. Links to the specific on-line ADHD sections of this research are also provided.


• In the Patterns of Regional Mental Illness Disorder Diagnoses and Service Use in Manitoba: A Population-Based Study deliverable by Martens et. al (2004), they investigated the treatment prevalence of ADHD disorders by RHA and RHA District. For more information, see section 2.12 Treatment Prevalence of ADD/ADHD
  
  
• In the Manitoba Child Health Atlas Update deliverable by Brownell et al. (2008), they investigated the prevalence of ADHD over two time periods: 2000/01 and 2005/06 and reported these rates by RHA, Winnipeg community areas, and by income quintiles.For more information, see section 7.3 ADHD
  
  
• In the Profile of Metis Health Status and Healthcare Utilization in Manitoba: A Population-Based Study deliverable by Martens et al. (2010), they investigated the prevalence of ADHD in children by RHA, Metis region and Winnipeg community areas. For more information on the prevalence of ADHD in this research, see section 8.6 Attention Deficit Hyperactivity Disorder Prevalence (ADHD)
  
  
• In the Health and Healthcare Utilization of Francophones in Manitoba by Chartier et al. (2012), they investigated and compared a Francophone cohort to a non-Francophone cohort and calculated the rate ratios for ADHD. For more information on the results of this research, see section 8.5 Attention–Deficit Hyperactivity Disorder (ADHD)
  
  
• In the How Are Manitoba's Children Doing? deliverable by Brownell et al. (2012), they investigated ADHD by looking at regional trends over time (2000/01 and 2009/10) by aggregate regions, age groups, and income quintiles and produced Lorenz Curves to help illustrate this socio-economic change over time. For more information on the results of this research, see the section titled Attention–Deficit Hyperactivity Disorder (ADHD)
  
  
• In The Educational Outcomes of Children in Care in Manitoba deliverable by Brownell et al. (2015), they investigated ADHD as part of a group of mental disorders, and compared three different cohorts: children in care, children receiving services from CFS (Child and Family Services), and children neither in care nor receiving services from CFS. For more information on the prevalence of ADHD in this research, see the section titled Mental Disorders
  
  
• In the Care of Manitobans Living with Chronic Kidney Disease deliverable by Chartier et al. (2015) they investigated the prevalence and relative risk of ADHD in children as a comorbidity to chronic kidney disease (CKD). For more information on prevalence and relative risk, see Table 5.2 Mental Disorders in Children.
  
  
• In The Mental Health of Manitoba's Children deliverable by Chartier et al. (2016) they investigated the prevalence of ADHD over two different time periods (2005/06-2008/09 and 2009/10-2012/13) by health region, Winnipeg community area, age groups and sex, and income quintile. For more information on the results of this research, see the section titled Attention-Deficit Hyperactivity Disorder

Cautions/Limitations

NOTE: Lists of drugs to treat diseases and conditions change all the time: new drugs are added, drugs are taken off the market, etc. Also it is very research specific. The list of medications presented in this concept represent a starting point and it is advisable to verify with a clinician or pharmacist the list of current medications being used in your research.