By Catherine A. Sanderson, Amherst College
Neurodevelopmental disorders get their name from the fact that they involve brain dysfunction and tend to begin early in life. This set of disorders includes intellectual disability (what was previously known as mental retardation) as well as various types of communication disorders.

Attention-deficit Hyperactivity Disorder (ADHD)
Two of the most common neurodevelopmental disorders are attention-deficit hyperactivity disorder (ADHD) and autism spectrum disorder. Both appear to have a combination of genetic and environmental causes.
ADHD, as the name suggests, actually consists of a deficit of attention and hyperactivity/impulsivity. Symptoms of inattention include being unorganized, having difficulty paying attention, and being easily distracted.
So, a child with these symptoms might constantly lose their coat, have trouble following directions from a coach, and focus on their peers instead of the teacher during school.
Hyperactive or impulsive symptoms include difficulty sitting still, rushing through tasks, and making rash decisions, such as suddenly deciding to quit the basketball team or start playing the violin. Some people show both inattention and hyperactivity/impulsivity symptoms.
ADHD in Adults
Historically in the field of psychology, ADHD was known as the “Hyperkinetic Reaction of Childhood”, and thought of as something one grew out of with age and maturity. We now know that this condition continues into adulthood, although the symptoms vary.
Some adults who actually have ADHD may never have been diagnosed but think of themselves as lazy or scatterbrained. For example, children with ADHD may be fidgety from having to sit in a classroom for long periods of time, whereas adults often have more flexibility about their work environments and can channel their energy in more adaptive ways.
But ADHD symptoms can interfere with functioning for adults, including in their relationships, work life, and health. Adults with ADHD may become bored easily, have trouble sitting through meetings, take a long time to finish work-related tasks, and have difficulty paying attention in conversations. It’s important to recognize that these symptoms aren’t a sign of being dumb or lazy or disrespectful, they are just symptoms of the disorder if it’s not being treated.
This article comes directly from content in the video series Introduction to Psychology. Watch it now, on Wondrium.
Autism Spectrum Disorder (ASD)
Like ADHD, autism, or autism spectrum disorder (ASD), is a lifelong developmental disorder. These symptoms are typically seen early in life, often before age three, and continue throughout the lifespan, although most people get better at being able to manage the symptoms if they receive intensive treatment.
There’s been controversy about what counts as autism since the Diagnostic and Statistical Manual of Mental Disorders (DSM’s) fifth edition in 2013 made a choice to combine four separate autistic disorders into a single disorder, known as Autism Spectrum Disorder.
Are Autism and Asperger’s Syndrome the Same?
People who had previously been diagnosed with Asperger’s syndrome—a disorder in which people have trouble with social functioning, including interpreting and responding appropriately to social cues and emotions—were now seen as having a form of autism.
Some people with Asperger’s didn’t think this shift made sense, in part because autism is typically characterized by more severe symptoms than seen with Asperger’s, including language delays and intellectual deficits.
A variety of high-functioning people have been diagnosed with Asperger’s syndrome, including Time magazine’s 2019 Person of the Year, climate activist Greta Thunberg. But experts in psychology and psychiatry felt that what differed was the severity of symptoms while otherwise having enough overlap to combine these two diagnoses into a single spectrum.
Spectrum Disorder
Challenges generally involve communication, motor skills, speech, and intellectual ability, but the specific symptoms and their degree vary widely; this is why it’s known as a spectrum disorder. The symptoms could include having extreme sensitivity to light, sound, touch, smell, or taste; finding seams or tags in clothing itchy and unbearable, for example.
There may be unusual motor behaviors, such as walking on their toes or hand flapping. In some cases, they may show unusual abilities in certain areas, such as music and math. Again, all of these symptoms can range from mild to severe, and different symptoms may be combined in different ways.

Genetics and Psychological Disorders
Although the specific symptoms of and diagnostic criteria for various disorders are distinct, the genetics underlying different disorders may be quite similar. In fact, a 2013 study that examined genetic sequencing in more than 50,000 people found clear evidence for genetic links between five different disorders: autism, ADHD, clinical depression, bipolar disorder, and schizophrenia.
People who had been diagnosed with one of these disorders showed distinct variations in four different genetic regions compared to people who had not been diagnosed with one of these. The genetic links were particularly strong between schizophrenia, depression, and bipolar disorder. However, once again, these genetic variations did not on their own predict these disorders. In other words, other factors clearly also influence whether someone develops a psychological disorder.
Common Questions about Understanding ADHD and Autism
Neurodevelopmental disorders get their name from the fact that they involve brain dysfunction and tend to begin early in life. This set of disorders includes intellectual disability (what was previously known as mental retardation) as well as various types of communication disorders.
Attention-deficit Hyperactivity Disorder (ADHD), as the name suggests, actually consists of a deficit of attention and hyperactivity/impulsivity. Symptoms of inattention include being unorganized, having difficulty paying attention, and being easily distracted.
Autism, or autism spectrum disorder (ASD), is a lifelong developmental disorder. These symptoms are typically seen early in life, often before age three, and continue throughout the lifespan, although most people get better at being able to manage the symptoms if they receive intensive treatment.