Attention-Deficit/Hyperactivity Disorder (ADHD)

Author Alyson Hait

Editor: Anna Chou



Attention-Deficit/Hyperactivity Disorder (ADHD) is a common diagnostic label for individuals suffering from attention deficit, excessive activity levels and impulsivity (Barkley, 2015). At the time of this publication, this genetically transmitted neurological disorder affects around 4-12% of school-aged children and 4-5% of college-aged students and adults, and exists as one of the most prevalent psychiatric disorders in children (Wilens et al., 2010; Barkley, 2015).

Children with ADHD grow up with some of the common symptoms including difficulty with attention, easy distractibility, forgetfulness, and difficulty sustaining mental focus (Gentile et al., 2006; Thapar et al., 2012). Even though many factors can contribute to causing ADHD, both drug and non-drug therapies are available for managing symptoms. This article outlines the diagnostic and rehabilitative processes of ADHD, while taking into consideration that the disorder resembles and coexists with other psychiatric disorders. 



Experts have yet to discern all possible factors contributing to the condition, although it has been researched that around 79% is derived genetically, with 11% being due to environmental factors (Thapar et al., 2012). People with ADHD can have difficulties with what is known as executive function, which is important for paying attention, inhibition of inappropriate behaviour, maintaining focus during mental tasks, with symptoms differentiating between individuals (Wilens et al., 2010). People with ADHD may have decreased brain size in the areas responsible for these executive functions, and brain development may peak at a later age (Wilens et al., 2010).

These factors, as well as others, are strongly influenced by genetics, and it is important to note that approximately fifty percent of parents diagnosed with ADHD will have children that suffer from the same disorder (Gentile et al., 2006); with it being two to eight times more prevalent in populations with first-degree relatives suffering from the same condition (Felt et al., 2014).



  • Difficulty sustaining attention
  • Forgetfulness
  • Distractibility
  • Hyperactivity/fidgeting
  • Restlessness
  • and impulsivity (Wilens et al., 2010).


Symptoms for ADHD should begin by the age of 7, and occur continuously in at least two settings (e.g., work, home, school, etc.) for a minimum of 6 months (Wilens et al., 2010). Adults can be diagnosed with the disorder, as long as they were diagnosed or presented with symptoms during their childhood (Gentile et al., 2006).


Risk Factors

  • Environmental factors
  • Maternal smoking
  • Alcohol
  • Drug use
  • Stress
  • Low birth weight
  • Premature birth
  • Dietary toxins
  • Anxiety
  • Poor social environment
  • Family difficulties
  • and poverty status (Thapar et al., 2012)



Although it is not necessarily predictive of ADHD due to the ambiguous nature of the disorder, the condition is most commonly diagnosed using the DSM-V (The Diagnostic and Statistical Manual of Mental Disorders) which gives the criteria for diagnosing all currently recognized mental health disorders (Hartung et al., 2019).

According to the DSM-V, children up to the age of 16 must have six or more symptoms, while those 17 or older must show five or more symptoms, and they should be seen for at least six months ongoing (Gentile et al., 2006). Although it is more reliably diagnosed during early childhood, adults may be diagnosed with ADHD, albeit with a varying degree in symptoms and presentation(e.g., hyperactivity in adults may appear as restlessness or anxiousness) (Gentile et al., 2006).

As a means to clinically diagnose the psychological disorder, computerized screening tests, rating scales and imaging are used as tools to evaluate patients (Nair et al., 2006). The criteria for diagnosing ADHD can be found via the DSM-V, alongside the list of potential symptoms mentioned above (Thapar et al., 2012). 

It is important to note that due to the symptoms of ADHD overlapping with a variety of disorder, differential diagnoses exist and need to be critically considered during a patient’s diagnostic evaluation periods (Gentile et al., 2006). Some of the differential diagnoses for ADHD include but are not limited to bipolar disorder, anxiety disorder, antisocial personality disorder, borderline personality disorder, and developmental disabilities (Gentile et al., 2006). Medical conditions that initially present as ADHD include but are not limited to seizure disorders, hyperthyroidism, lead toxicity, sleep apnea, and head injuries (Gentile et al., 2006).  



Pharmacological Treatment

The overall goal of pharmacological treatment in ADHD is to secure enhanced levels of attention, improved academic performance, working memory, reduced aggression and psychomotor activity to name a few (Gentile et al., 2006). The most highly efficacious drugs have been found to be psychostimulant drugs such as Ritalin, Concerta, Focalin, Adderall, or Dexedrine, all of which are commonly used to treat ADHD (Wilens et al., 2010). Even though these drugs may cause some side effects such as decreased appetite, decrease in cardiovascular health, and insomnia with an increased risk of stimulant abuse, they have also been researched and shown to improve ADHD symptoms amongst all age groups (Wilens et al., 2010).


Non-pharmacological Treatment

ADHD management can also involve non-drug options that instead include behavioural treatment methods such as psychotherapy, which involves addressing emotions and creating strategies for managing behaviours without medications (Wilens et al., 2010). Tutoring is often recommended, as well, for children that struggle in a school environment (Wilens et al., 2010). More recent therapies, such as cognitive behaviour therapy, which involved altering thought patterns and beliefs to create positive changes in behaviour, have shown promise in managing ADHD symptoms, especially in adults (Wilens et al., 2010).


Articles on Misdiagnosis 

Barkley, R. A. (2010). Differential Diagnosis of Adults With ADHD: The Role of Executive Function and Self-Regulation. The Journal of Clinical Psychiatry, 71(7), 0–0. doi:10.4088/JCP.9066tx1c.

Manos, M. J., Giuliano, K., & Geyer, E. (2017). ADHD: Overdiagnosed and overtreated, or misdiagnosed and mistreated. Cleveland Clinic Journal of Medicine, 84(11), 873–880. doi:10.3949/ccjm.84a.15051.

Taurines, R., Schwenck, C., Westerwald, E., Sachse, M., Siniatchkin, M., & Freitag, C. (2012). ADHD and autism: Differential diagnosis or overlapping traits? A selective review. ADHD Attention Deficit and Hyperactivity Disorders, 4(3), 115–139.


Barkley, R. A. (2015). History of ADHD. In Attention-deficit hyperactivity disorder: A handbook for diagnosis and treatment, 4th ed (pp. 3–50). The Guilford Press.


Felt, B. T., Biermann, B., Christner, J. G., Kochhar, P., & Harrison, R. V. (2014). Diagnosis and Management of ADHD in Children. American Family Physician, 90(7), 456–464.

Gentile, J. P., Atiq, R., & Gillig, P. M. (2006). Adult ADHD. Psychiatry (Edgmont), 3(8), 25–30. 


Hartung, C. M., Lefler, E. K., Canu, W. H., Stevens, A. E., Jaconis, M., LaCount, P. A., Shelton, C. R., Leopold, D. R., & Willcutt, E. G. (2019). DSM-5 and Other Symptom Thresholds for ADHD: Which Is the Best Predictor of Impairment in College Students? Journal of Attention Disorders, 23(13), 1637–1646. doi:10.1177/1087054716629216.

Nair, J., Ehimare, U., Beitman, B. D., Nair, S. S., & Lavin, A. (2006). Clinical review: Evidence-based diagnosis and treatment of ADHD in children. Missouri Medicine, 103(6), 617–621.

Thapar, A., Cooper, M., Jefferies, R., & Stergiakouli, E. (2012). What causes attention deficit hyperactivity disorder? Archives of Disease in Childhood, 97(3), 260–265.

Wilens, T. E., & Spencer, T. J. (2010). Understanding Attention-Deficit/Hyperactivity Disorder From Childhood to Adulthood. Postgraduate Medicine, 122(5), 97–109.


Print this Article

Mini Disclaimer

User discretion: The material presented here is for your information and to be used for your reference only. Our volunteers have sourced this information from reputable sources and made sure it meets the quality standards at MARI. The information presented is not intended to be used as a diagnostic tool, a basis upon which to make diagnostic decisions, or to substitute the advice of a medical or healthcare professional. 

If you are a patient experiencing any of the listed symptoms, please consult a healthcare provider for specialized care and follow the instructions provided for you by your doctor. If you are in the US and would like advice on a possible case leading to errors in medicine, please reach out to our MARI Consultation team.

We appreciate your feedback!

Thank you for visiting our website. We are always looking for ways to improve. Please take a moment to tell us about your experience.