This week, we’re focusing on understanding what Attention Deficit Hyperactivity Disorder (ADHD) really means, as more people are being diagnosed. While increased awareness has grown, confusion remains about what ADHD is. ADHD is not simply “being easily distracted” or “always on the go.” It involves significant challenges that need the right support. Today, let’s clarify the true meaning of ADHD and how professionals approach treatment.
What is ADHD?
ADHD, or Attention Deficit Hyperactivity Disorder, is a psychiatric condition that affects a person’s mental health. People with ADHD often have trouble staying focused on tasks and goals, show high levels of hyperactivity, and act impulsively (1). In the past, ADHD and ADD (Attention Deficit Disorder) were considered separate, but now they are grouped together and divided into three types: Predominantly Hyperactive, Predominantly Inattentive, or Combined Type (1,2). These categories are listed in the DSM, a guide used to define mental health disorders. The DSM helps doctors diagnose ADHD by reviewing reports from the person and others who know them, such as family, friends, or colleagues. These outside perspectives help us determine whether the symptoms are serious enough to affect daily life and whether they have persisted long enough to be considered ADHD (2).
If you’d like to see the criteria, check the signs and symptoms section below, where you’ll also find a website for more information.
Causes and Risk Factors
Like many mental health conditions, ADHD doesn’t have a single known cause. Both genetics and environment play a role in its development. While ADHD often runs in families, no specific gene has been linked to it. Studies show that twins are twice as likely to have ADHD compared to the general population. Some researchers think that a brain chemical called dopamine may be involved. An imbalance of dopamine might cause the symptoms and behaviours seen in people with ADHD.
Other studies suggest that certain choices during pregnancy can affect the baby and may lead to ADHD later on. These include smoking, drinking alcohol, or not getting enough nutrients while pregnant.
Other risk factors linked to ADHD include (4):
- Premature birth – While not all babies born early will have ADHD, they are at higher risk because of factors like lower birth weight and slower brain development (3).
- Pesticide exposure – Some studies have found a link between certain pesticides and symptoms similar to ADHD (5).
- Mercury exposure – One study suggested a possible link between mercury exposure and ADHD, but there isn’t enough evidence to say mercury causes ADHD (6).
- Sleep disorders or sleep deprivation – Some studies suggest that a lack of sleep can make children more hyperactive, and in adults, it can keep them awake even when they feel tired (7).
How Common is ADHD?
ADHD is being diagnosed more often now because there’s more information available, leading more people to wonder if they have it. As conversations about neurodivergence and conditions like ADHD, Tic Disorders, and Autism become more common, more people are asking their GP for a diagnosis. The media is also covering ADHD more than before (8). This rise in diagnoses has led to some challenges, such as a shortage of medications, since they are being prescribed more often (8, 9). As more people seek help and medication becomes harder to get, it’s becoming more difficult to support everyone with ADHD.
Recent data shows that about 5% of children worldwide have ADHD, with boys diagnosed more often than girls. This doesn’t mean boys are more likely to have the condition, but rather that there are biases in how it’s diagnosed. Boys are usually referred for assessment when they exhibit disruptive behaviour, whereas girls often present with the inattentive type, which is easier to overlook (10).
In the UK, about 3-4% of adults have been diagnosed with ADHD, with men diagnosed more often than women (10).
ADHD is also more common among people from lower-income backgrounds, those who are unemployed, or those in lower social classes (10).
Signs and Symptoms
How do we decide if someone has ADHD? As mentioned earlier, doctors use the DSM criteria (2). ADHD is defined as a lasting pattern of inattention and/or hyperactivity-impulsivity that gets in the way of daily life or development. The DSM doesn’t give a definite answer, but it offers a reliable guide for professionals to use when diagnosing different people.
According to the DSM, symptoms of Inattention are:
- Often fails to give close attention to details or makes careless mistakes in schoolwork, work, or other activities.
- Often has difficulty sustaining attention in tasks or play activities.
- Often does not seem to listen when spoken to directly.
- Often does not follow through on instructions and fails to finish schoolwork, chores or duties in the workplace (not due to oppositional behaviour or failure to understand instructions)
- Often has difficulty organising tasks and activities.
- often avoids, dislikes, or is reluctant to engage in tasks that require sustained mental effort (such as schoolwork or homework)
- often loses things necessary for tasks or activities (e.g., toys, school assignments, pencils, books or tools)
- is often easily distracted by extraneous stimuli
- is often forgetful in daily activities
To be diagnosed with Predominantly Inattentive ADHD, a person must show at least six of the symptoms listed above.
Symptoms of Hyperactivity are:
- Often fidgets with hands or feet or squirms in the seat.
- Often leaves the seat in the classroom or in other situations in which remaining seated is expected.
- Often runs about or climbs excessively in situations in which it is inappropriate (in adolescents or adults, may be limited to subjective feelings of restlessness)
- Often has difficulty playing or engaging in leisure activities quietly.
- Is often “on the go” or often acts as if “driven by a motor”
- Often talks excessively
Symptoms of Impulsivity are:
- Often blurts out answers before questions have been completed.
- Often has difficulty awaiting turn.
- Often interrupts or intrudes on others (e.g., butts into conversations or games)
To be diagnosed with Predominantly Hyperactive ADHD, a person must show at least six of these symptoms.
For a combined type diagnosis, a person must have symptoms from both groups.
For all these diagnoses, the symptoms must (11):
- be present in more than one social setting, e.g. school and home.
- be shown in the individual for at least 6 months
- interfere with regular functioning in social, academic, or occupational settings
- not be seen only during an extreme mental health crisis event
For a clear summary of these symptoms, visit the CDC website Diagnosing ADHD (12): https://www.cdc.gov/adhd/diagnosis/index.html.
How is ADHD Treated?
ADHD is mainly treated with medication, but psychological and social approaches are also important, as with other mental health conditions.
Medications
Medications fall into two main groups: stimulants and non-stimulants (1).
Stimulants are the first choice for treating ADHD because they help balance brain chemicals that are thought to cause ADHD symptoms. When these chemicals are balanced, people can focus and think more clearly, which helps reduce the impact of ADHD on daily life. Stimulants come in long-acting and short-acting forms and are chosen based on each person’s needs (13).
Non-stimulants can also help with ADHD symptoms, but they work differently and don’t directly increase the levels of these brain chemicals.
Both types of medication have their own side effects, and the choice depends on what works best for each person.
Psychological and Social Approach
Patients can attend education sessions to learn how to manage their symptoms. Families may be offered therapy to help create a supportive environment for their loved one with ADHD. Support groups are also available for both children and adults with ADHD.
With ADHD getting more attention, it can be tempting to think it explains every symptom or behaviour you notice. While that might be the case for some, it’s important to understand what ADHD really is before self-diagnosing, as it can be a challenging condition to manage. If you think you have signs of ADHD, talk to your GP about getting a referral for a proper diagnosis.
References:
- National Institute for Health and Care Excellence. Attention-Deficit/Hyperactivity Disorder: diagnosis and management [Internet]. London: NICE; 2018 [cited 2025 Dec 05]. Available from: https://www.ncbi.nlm.nih.gov/books/NBK441838/
- National Institute for Health and Care Excellence. ADHD: background information – definitions and classifications [Internet]. London: NICE; 2018 [cited 2025 Dec 05]. Available from: https://www.ncbi.nlm.nih.gov/books/NBK519712/table/ch3.t3/
- Aylward GP. Neurodevelopmental Outcomes of Infants Born Prematurely. Journal of Developmental & Behavioral Pediatrics, 2005 Dec. 26(6):427-440.
- Núñez-Jaramillo L, Herrera-Solís A, Herrera-Morales WV. ADHD: Reviewing the Causes and Evaluating Solutions. Journal of Personalized Medicine. 2021; 11(3):166
- Richardson JR, Taylor MM, Shalat SL, Guillot TS 3rd, Caudle WM, Hossain MM, Mathews TA, Jones SR, Cory-Slechta DA, Miller GW. Developmental pesticide exposure reproduces features of attention deficit hyperactivity disorder. FASEB J. 2015 May;29(5):1960-72
- Barry MJ, Almotawah F, Pani SC, Ingle NA. A Comparison of Salivary Mercury Levels in Children with Attention Deficit/Hyperactivity Disorder When Compared to Age-matched Controls: A Case-control Observational Study. Journal of Contemporary Dental Practice. 2020; 21 (2):129-132
- Bijlenga, D., Vollebregt, M.A., Kooij, J.J.S. et al. The role of the circadian system in the etiology and pathophysiology of ADHD: time to redefine ADHD?. ADHD Attention Deficit Hyperactivity Disorders. 2019 11:5–19
- Martin AF, Rubin GJ, Rogers MB, Wessely S, Greenberg N, Hall CE, Pitt A, Logan PE, Lucas R, Brooks SK. The changing prevalence of ADHD? A systematic review. 2025 Nov. 388.
- Medical Xpress. Frustrations rise as shortage of ADHD medication leaves patients in limbo [Internet]. 2024 Feb [cited 2025 Dec 05]. Available from: https://medicalxpress.com/news/2024-02-frustrations-shortage-adderall-adhd-medication.html
- National Institute for Health and Care Excellence. Attention deficit hyperactivity disorder: background information – prevalence [Internet]. London: NICE; 2022 [cited 2025 Dec 05]. Available from: https://cks.nice.org.uk/topics/attention-deficit-hyperactivity-disorder/background-information/prevalence/
- National Institute for Health and Care Excellence. Attention deficit hyperactivity disorder: background information – definition [Internet]. London: NICE; 2022 [cited 2025 Dec 05]. Available from: https://cks.nice.org.uk/topics/attention-deficit-hyperactivity-disorder/background-information/definition/
- Centers for Disease Control and Prevention. ADHD Diagnosis [Internet]. Atlanta (GA): CDC; 2023 [cited 2025 Dec 05]. Available from: https://www.cdc.gov/adhd/diagnosis/index.html
- Mechler K, Banaschewski T, Hohmann S, Häge A. Evidence-based pharmacological treatment options for ADHD in children and adolescents. Pharmacology & Therapeutics. 2020 Feb. 230.
