It seems as though hardly a day goes by without a story related to ADHD appearing in the news - but what is behind this sudden rise of ADHD? In order to answer this question, it is helpful to look back at the evolution of the condition as we know it today.
What exactly is ADHD?
Whilst it is often referred to as a recent phenomenon, chronic attention deficits in children, matching modern descriptions of ADHD, were first described by the Scottish physician Sir Alexander Crichton way back in 1798. In the early 1980s, The American Psychological Association (APA) officially recognised Attention Deficit Disorder (ADD) as a childhood disorder. However, by 1987, research had revealed new insights about the condition, leading to its renaming as Attention Deficit Hyperactivity Disorder (ADHD). In the UK, the NHS recognised ADHD as a childhood disorder in 2000, and an adult disorder in 2008.
The diagnostic criteria for ADHD are based on two main categories of symptoms: attention deficit and hyperactivity. Symptoms of attention deficit include trouble concentrating, difficulty following instructions, and forgetfulness. Hyperactivity is characterised by restlessness, impulsiveness, and excessive physical movement. Depending on the symptoms, ADHD can be diagnosed as predominantly inattentive, predominantly hyperactive/impulsive, or combined. For a clinical diagnosis to be made, these symptoms must be shown to cause significant impairment to the individual and to have been present since childhood.
Why are diagnoses on the rise?
It is worth noting that the recent increase in ADHD diagnoses does not necessarily mean that there has been a sudden rise in the number of ADHD cases. Instead, it is more likely due to changes in diagnostic criteria, such as the inclusion of inattentive symptoms in 1994, the recognition of adult ADHD in 2008, and greater awareness of how ADHD presents, especially in women and girls.
What causes ADHD?
Although the exact causes of ADHD are not fully understood, researchers have identified apparent neurological factors that are closely correlated with this condition. Deficits in neurotransmitters, such as dopamine, are associated with ADHD. Dopamine levels are affected by oestrogen levels, so for girls and women with ADHD, the menstrual cycle, pregnancy, and menopause are believed to influence their symptoms. Structural abnormalities in the brain, including a slightly smaller prefrontal cortex and basal ganglia, have also been linked to ADHD. While no single gene is associated with this condition, there is a strong genetic component, with heritability estimated at around 80%, meaning that ADHD often runs in families.
What are the treatments for ADHD?
A diagnosis of ADHD can be a valuable step for individuals, as it can provide a better understanding of their challenges. Research suggests that effective treatments for ADHD include therapy, coaching, and medication, such as the stimulant methylphenidate (e.g., Ritalin), which has a paradoxically calming effect on individuals with ADHD, allowing them to focus and regulate their behaviour better.
What's the future for ADHD?
It is unlikely that we will see a downturn in diagnostic rates anytime soon - and with good reason. For decades, ADHD has been underdiagnosed, especially in women, girls, and those with predominantly inattentive symptoms, so there is much catching up to do. Our understanding of the condition will likely evolve as more research is conducted. For example, it is widely reported that there are numerous ADHD symptoms, such as rejection sensitivity dysphoria (RSD), that the diagnostic criteria do not currently recognise. If further research confirms the existence of these anecdotal symptoms, the diagnostic requirements will likely be expanded to include them, further increasing the number of individuals who meet the diagnostic criteria for diagnosis. Increased diagnosis rates are a positive outcome, as the symptoms of ADHD are persistent and pervasive. For example, untreated ADHD can negatively affect mental health (it is associated with higher rates of anxiety and depression), physical health (it is associated with higher rates of addiction), and relationships (divorce is more common amongst those with ADHD). Fortunately, ADHD is highly responsive to treatment; therefore, increased diagnoses can lead to better outcomes for more people.