The central nervous system is a delicate and complex mechanism, and disruptions to the functioning of the CNS are collectively known as neurodevelopmental disorders. The conditions that fall under this umbrella range from attention deficit hyperactivity disorder, to dyslexia, to autism spectrum disorder. Issues of neurodevelopmental disorders and drug abuse concern to what degree the impacted central nervous system compels individuals to misuse drugs and how drug abuse can damage the CNS.
Nature magazine explains that the term neurodevelopmental disorders refers to a group of disorders that disturb the development of the central nervous system, the arrangement of nerve tissues that control the many activities of the body. In human beings, the CNS is made up of the brain and the spinal cord.1 When disruptions happen, they change the function of the brain, which presents in the form of neuropsychiatric problems, such as various forms of intellectual disabilities, or impaired motor functioning. Patients also experience difficulties with language and nonverbal communication.23
There are many kinds of neurodevelopmental disorders. Some of them are caused by genetics, and others by exposure to harmful stimuli in the womb and during key postnatal developmental stages. Some might never be fully understood.4
Neurodevelopmental disorders can form at any point in a person’s life, but special attention is given to the formation of neurodevelopmental disorders in children. NeuronUp explains that a child’s brain is not just a smaller version of an adult brain; it is a brain “in continual development.”5 The growth of a child’s brain takes place at a rapid pace, endlessly changing and wiring itself with every stimulation the child receives. Whether at home or preschool, and even during rest, the child’s brain is in a constant state of change and evolution, learning from its environment in ways adult brains do not have to.
This is important to understand because it is at this stage that disruptions to the nascent central nervous system can have lifelong consequences. Some neurodevelopmental disorders can be resolved with appropriate medical and therapeutic interventions; others are long lasting, but nonetheless require appropriate treatment because alleviation of symptoms is still possible. It might even be possible to eliminate the worst of the symptoms caused by the disorder.
One of the most well-known neurodevelopmental disorders is attention deficit hyperactivity disorder (ADHD), known for presenting symptoms that mimic compulsive inattention or impulsivity-hyperactivity.6 There are subtypes of the condition, which are largely based on if its predominant symptom is the attention deficit, the impulsive hyperactivity, or both.
Patients with ADHD tend to present with inattention, which appears as a lack of attention to detail and frequently making mistakes. They struggle to concentrate in work and in play alike. They are very easily distracted and do not appear to listen when addressed directly. Those with the predominantly hyperactive ADHD subtype will not be able to control fidgeting in the hands and feet. They display “excessive” energy and can be physically disruptive in social settings; adult sufferers describe this as a state of constant restlessness.
When it comes to cognitive skills and neurodevelopmental disorders, everyone develops such skills in their own way, but if a particular deficiency exists in an area of development, this becomes a specific problem in learning, which usually presents itself in the form of lower-than-average academic performance for their respective age. This most obviously impacts school performance, and it can impair academic goals and progression for years to come.
Attention deficit hyperactivity disorder is one of the most common forms of a neurodevelopmental disorder. The Centers for Disease Control and Prevention notes that 11 percent of school-aged children in America received a diagnosis of ADHD from their doctor, and the percentage of children who receive such a diagnosis has been increasing.7
Examples of learning-related neurodevelopmental disorders include dyslexia, a reading order whereby patients cannot recognize words; they read slowly out of a sense of insecurity about comprehending written words and struggle to process what they can read. Dyslexia is one of the most frequently occurring language-based learning disability, and it is responsible for most of the difficulties in spelling, writing, and reading that people have.
Of those who have such struggles, as many as 80 percent of them have some variation of dyslexia. It is possible that 17 percent of the general population could have this neurodevelopmental disorder; however, it may not be recognized and diagnosed in some people, leading to a lack of treatment and access to treatment. Some might resist the diagnosis, out of shame as being thought of as illiterate or uneducated. Because of these reasons, it is difficult to precisely determine the full prevalence of dyslexia.8
Other kinds of neurodevelopmental disorders that affect learning are dysgraphia, a disorder that affects the writing of specific words or the cognitive and physical act of writing in general. Similarly, dyscalculia inhibits the development of basic arithmetic skills, such as addition or subtraction, more so than the abstract math skills of algebra or geometry.9
Communication and expression disorders account for a large share of the most common forms of neurodevelopmental disorders. When the development of the language centers of the brain does not follow the typical route, or significant problems occur in the formation of those centers, the usual presentation is a communication disorder. Having said that, the characteristics of such disorders can vary greatly, depending on the nature of the disruption and the age of the child in question when it happened.10
The range of communication disorders is wide. Symptoms may include limited speech, limited vocabulary, difficulty adding new words to the vocabulary, restricted use of grammatical structures, an inability to say critical parts of sentences, unusual order of words in a sentence or thought, and a regression in age-appropriate language development.11
When one set of development parameters is impaired for whatever reason, at a critical juncture in the child’s development, it can push other development parameters off course. As an example, comprehension disorder represents a significantly below-par ability to comprehend words, phrases, or specific forms of words because the formation of expressive language skills is based on the learning of receptive skills.
Perhaps the most well-known of neurodevelopmental disorders are the group of developmental disabilities known as autism spectrum disorders (ASD), which can cause significant and long-term problems with socialization, expression, communication, and behavior. ASD presents very differently in one child to another, which is why the range of disabilities is categorized on a spectrum. There are a number of different ways that the symptoms of autism spectrum disorder appear, and the severity of those symptoms can differ greatly from patient to patient.
As a neurodevelopmental disorder, ASD conditions make patients process information in their brain differently than people without ASD. These present with extreme difficulties in social communication (difficulty in understanding nonverbal and verbal communication, a lack of social reciprocity, and an inability to develop and maintain age- and developmentally appropriate peer relationships). The difficulties are not merely passing phases; they are clinically significant. Autism spectrum disorder also causes unusual sensory behavior, stereotypical movement or verbal behavior, and an obsessive adherence to ritualistic patterns, often to the exclusion of other interests.
The Diagnostic and Statistical Manual of Mental Disorders (DSM) is a publication issued by the American Psychiatric Association to help clinicians and psychiatrists diagnose the hundreds of known and identified mental illnesses. The DSM encompasses all categories of mental health conditions, for adults and children alike, and is often referred to even outside the treatment field (for example, to determine whether a condition is disruptive enough to warrant insurance coverage). The manual focuses on identifying symptoms of a condition, as well as the statistics regarding which gender or age group is most likely to be affected by a particular condition. It also looks at the accepted treatment approaches and how effective there are.
The first version of the Diagnostic and Statistical Manual was published in 1952; the most recent version, DSM-5, came out in 2013.12 One of the most significant revisions of the fifth version was a change to the organization of criteria for autism and similar disorders. The chapter on neurodevelopmental disorders was updated to include “social communication disorder,” which grouped many related disorders (autism, Asperger’s, childhood disintegrative disorder, and pervasive developmental disorder-not otherwise specified, or PDD-NOS) into a single diagnostic autism spectrum disorder category.13
A report published in the Journal of Autism and Developmental Disorders noted that between 19 percent and 30 percent of people who are diagnosed with autism, “present with comorbid substance abuse problems.” Researchers suggested that one of the risk factors for drug abuse among this population with neurodevelopmental disorders is the diagnosis of attention deficit hyperactivity disorder, which does frequently develop in people who have autism spectrum disorder.14 A study in Sweden of almost 30,000 people with ASD revealed that the diagnosis of being on the autism spectrum was usually accompanied with a twofold risk for a number of drug and alcohol problems. The authors of the study suggested that there is a shared risk of substance abuse in families that have at least one member with ASD.15
Other research, such as that published in the American Journal of Family Therapy, notes that there is a fair amount of stress that comes with the diagnosis of autism, especially if the patient in question is a child. The journal identified such problem areas as communication and bonding within the family unit, as well as disruptions to sleep patterns for both the patient and the family, and various other changes that have to be made as the result of the diagnosis.16
These factors combine for a high risk of substance abuse among people with ASD. A study conducted by the Washington University School of Medicine found that people who had the symptoms of autism (but not necessarily the accompanying diagnosis) were more likely than people without such symptoms to abuse alcohol and marijuana. A press release that accompanied the research noted that people who have autistic traits might not be seen to drink because they tend to be more socially withdrawn, but “if they do start drinking, they tend to repeat that behavior,” both as a function of their neurodevelopmental disorder, and the addictive potential of alcohol (or the drug in question).
The difference between this study and others that have suggested that people with ASD have a lower risk of substance abuse is that people with milder ASD or ADHD symptoms might not be diagnosed with their respective disorder. The symptoms can be so slight as to appear to be standard communications- or expressions-based disruptions, even though they would fall on the spectrum of autism and/or attention deficit disorders. Some neurodevelopmental disorders might insulate patients from the risk factors of substance abuse; others might elevate that risk.17
In general, neurodevelopmental disorders “result in lifelong cognitive and behavioral defects,” according to the Nature Reviews Drug Discovery journal, and these easily overlap with substance use disorders that patients develop as a coping mechanism for the initial stressors.18 Treating these co-occurring disorders requires special care. In 2016, the Substance Abuse: Research and Treatment journal noted that routine clinical assessments do not typically screen for autism spectrum disorder (as an example of a neurodevelopmental disorder) and substance use disorder, and this puts patients at an obvious risk if they are placed on pharmaceutical therapies that react negatively to the presence of other drugs and alcohol in their systems.19
One therapy that has shown promise is Cognitive Behavioral Therapy (CBT), which has been used to help patients with ASD control their anxiety-related symptoms.20 CBT is also widely used in the treatment of substance use disorders, informing patients as to how they can control the thought patterns that lead to harmful drug and alcohol use, and how they can change those patterns into more productive behaviors. Conceivably, Cognitive Behavioral Therapy could work with patients who suffer anxiety as a result of the symptoms of their neurodevelopmental disorders, and who channel that anxiety into self-destructive behaviors, such as alcohol abuse; however, there remains “much distance,” in the words of researchers in Current Opinions in Neurology, about using CBT on a fuller scale to address the crossover between the two disorders.
Neurodevelopmental disorders make it difficult for patients to discern another person’s emotions, form interpersonal connections with other people, and apply the experiences of others to their own lives. For example, people with autism can feel empathy, but their ASD renders them incapable of expressing the empathy in ways that people without ASD can recognize or appreciate.21 This will impact the effectiveness of certain behavioral-based treatment options, like Cognitive Behavioral Therapy. While CBT has shown success in working with people on the autism spectrum and who may have other presentations of neurodevelopmental disorders, it is still a behavioral intervention for a neurobiological disorder, and as such, it is not a comprehensive solution.
However, in examining “The Hidden Link Between Autism and Addiction,” The Atlantic notes that new research that has uncovered the unexpected biological and psychological similarities between neurodevelopmental disorders and drug abuse has enthused scientists. The University of Minnesota Twin Cities has opened a lab that specifically deals with the study of the biological and behavioral commonalities between autism and substance abuse. Preliminary tests have found that those who develop emotional problems to cope with autism or hyperactivity disorder share the same genes as those who instigate the development of substance abuse for the same purpose. In theory and in time, this could lead to treatment forms that better address both autism and neurodevelopmental treatment as well as addiction prevention.22