ADHD, and Substance Dependence

ADHD (Attention Deficit/Hyperactivity Disorder) is commonly associated with high risk behaviours including substance abuse and dependency. Similar to a genetic predisposition, ADHD and addiction are thought to be connected, either causally or co-occurring. Typically emerging in childhood, ADHD affects between 3 and 5 percent of girls and boys under the age of 12 years. A further 2 to 4 percent of adults suffer from ADHD with up to 25 percent experiencing both ADHD and substance abuse or dependency.

Such high statistical correlations has led medical professionals and researchers to study the connection between ADHD and addiction. Besides any co-occurring or causal connections, there is a concern as to whether medications used to treat ADHD could be in and of themselves addictive, thereby acting as a gateway to substance addiction and misuse.

Article Contents

This special article on ADHD and Substance Dependence (Misuse) will first describe ADHD in outline form, and then discuss recent findings regarding ADHD and Substance Abuse/Misuse/Dependence.

Attention Deficit/Hyperactivity Disorder (ADHD) and its Symptoms

Attention deficit hyperactivity disorder, also known as ADHD, is a type of brain disorder noted for ongoing patterns of impulsivity, hyperactivity, and inattention that disrupt daily functioning and overall human development.1 There are generally speaking three ADHD diagnostic criteria:

  • Inattention – When a person lacks persistence, is unable to focus, wanders off tasks, and is disorganized not from defiance or the inability to understand.
  • Hyperactivity – Constantly moving, particularly in situations that are not appropriate. Excessive fidgeting, tapping, or talking can also be described as hyperactive behaviours. In adults, severe restlessness or the inability to relax may be prominent.
  • Impulsivity – Hasty actions that are not thought through, or could be deemed risky, are considered as impulsivity. A person may also have a strong urge for immediate rewards, be socially intrusive, or fail to address long term consequences of their decisions and actions.

While inattention and hyperactivity are the primary behaviours of ADHD, children and adults can exhibit one or the other, but most experience both to some degree. It is important to note that every person does experience some amount of inattention or impulsivity, but for people who have ADHD, the behaviours are more severe, occur frequently, and can interfere with their social, familial, school, or work life.

Diagnosing ADHD requires a comprehensive assessment and evaluation by a psychologist, psychiatrist, or licensed clinician with experience in the disorder. In general, the symptoms must be chronic and long lasting. They will also impair the individual's functioning leading to a slowed development for his or her age. Usually, children receive the diagnosis while in elementary or primary school. To be diagnosed as an adult or teen, the patient must show the symptoms were present prior to the age of 12.

Unfortunately, the symptoms of ADHD can be mistaken for emotional or disruptive problems; thus leading to unnecessary discipline. In other instances, it is left unnoticed. Both can contribute to a delay in diagnosis as well as have an impact on a person's emotional wellbeing and self confidence.

The symptoms of ADHD can change with time, and as a person grows older. In children, hyperactivity tends to be predominating; whereas, as the child grows, inattention may takeover. Adults might experience inattention, impulsivity, and restlessness.

Origins of ADHD Diagnostics

In 1968, the Diagnostic and Statistical Manual of Mental Disorders II (DSM) first published a condition called hyperkinetic reaction of childhood. There have been reports of similar conditions and symptoms dating back to the 17th century. In the third edition of the DSM, published by the American Psychiatric Association in 1980, the term was modified into ADD or Attention Deficit Disorder. The later fourth edition again changed the term, which was reflective upon research findings. It was called Attention Deficit Hyperactivity Disorder, or ADHD. The most current and fifth edition continues to use this term and has also added three sub specifications which are:

  • Predominantly inattentive presentation
  • Predominantly hyperactive and impulsive presentation
  • Combined presentation

Males tend to exhibit both presentations; whereas females tend to exhibit the first.

Studies Comparing ADHD and Substance Abuse Disorders

Only recently has medical professional begun to take interest in the association between ADHD and substance abuse disorders. Much of the research is still ongoing as of 2017, and will be released to the educational system and community in the near future. The following are published studies that highlight ADHD and substance use.

Treatment Strategies for Co-Occurring ADHD and Substance Use Disorders

One 2005 study assessed current treatment protocols for ADHD patients. Pharmacotherapy, including psychostimulant medications, is the mainstay of treatment. However, many medical clinicians seek different approaches to treating those with a substance abuse disorder and ADHD, particularly which do not include stimulants. This study attempts to address the correlation between the two and make recommendations for treating patients with co-occurring substance use disorders and ADHD.

The National Comorbidity Survey Replication (NCS-R) published a survey that included ADHD. It found 4.4% of US adults had ADHD. The rate of occurrence with people who had a substance use disorder and ADHD was found to be at 15.2% as compared to 5.2% of people who did not have ADHD. Furthermore in 10.8% of people who had a substance use disorder, there were enough criteria to ascertain adult ADHD, though they had not been officially diagnosed as such.2

This study goes on to discuss evidence which suggests the theory that dopamine neurotransmission dysfunction and genes associated with neurotransmitter could be partially responsible for ADHD. In particular the D2 dopamine receptor gene, the dopamine-hydroxylase gene, the dopamine transporter(DAT) gene, the SNAP-25 gene, the D4 dopamine receptor gene, in addition to others.3 The development of substance use disorders has also been linked to the same genes which indicate there could be common factors leading to the development of the co-occurring disorders.

By clinical definition, Childhood ADHD is exhibited in children prior to the age of 7, whereas substance use disorders often develop during adolescence or adulthood. Some researchers believe that substance use is a coping method or developmental interaction with symptoms of ADHD.

Furthermore the impulsivity, poor academic performance, inability to focus, and social stigmas create an opportunity for a person to have motivation for substance use, resulting in potential misuse. The risks of this development are also dependent on the severity of the symptoms, rather than only meeting the criteria of ADHD.

The study concludes with suggestions on how patients with ADHD and a substance abuse disorder should be treated. It is suggested that substance use represents an attempt to self-medicate the negative social and psychological impact of ADHD.

Medication, typically psychostimulants, are the first line of treatment because they can stimulate and balance the dopamine receptors in the brain.4 Non-stimulant medication is available, and promising, but their ability to help patients with the co-occurring disorders is unknown. Due to the addictive nature of psychostimulants, the study recommends use with caution for patients who have a substance use disorder.

A conservative approach to this treatment would be to treat the co-occurring ADHD and substance use disorder with a non stimulant medication. If a desired response is not noticeable, stimulant pharmacotherapy could be an option. Cognitive behavioural therapy, counselling, and exercise can also be valuable forms of treatment.

Correlates of co-occurring ADHD in drug-dependent subjects: Prevalence and features of substance dependence and psychiatric disorders

Another relevant study examined the prevalence and course of substance use and psychiatric disorders in people who have ADHD.[^co-occurring-adhd] Interviews on 1761 adults who had been diagnosed with a cocaine or opioid dependency had been conducted. Generalized estimating equation analysis and linear regression was used to identify correlations between ADHD diagnoses. The results suggested that people with a substance use disorder and ADHD was 5.22% versus 0.85% in people without a substance use disorder.

The study also showed in people who exhibited the symptoms of ADHD also had an earlier age of substance use, psychiatric diagnosis, and mental health hospitalizations which suggests that behavioural disorders were also an issue. The conclusions of the study suggested that in patients who had a cocaine or opioid dependence, ADHD was prevalent in addition to psychiatric co morbidity. Ideally with these results, better treatment approaches can be taken to lessen the symptoms and effects of all issues.

Does Attention-Deficit Hyperactivity Disorder Impact the Developmental Course of Drug and Alcohol Abuse and Dependence?

One of the preliminary studies on ADHD and substance use disorder examined the effects on the transitions from abuse to dependence, and between the agents of use.5 A sample of 239 male and female adults who had been diagnosed with ADHD as a child, were interviewed and compared to 268 non-ADHD healthy adults.

The results showed that the subjects with ADHD had a twofold increased risk for developing a substance use disorder. Furthermore, they were more likely to make the transition from alcohol to drugs. It concluded by saying that subjects with ADHD and early alcohol use disorder were at risk for subsequent abuse that included other drugs. Such developmental pathways might be prevented by developing and implementing early intervention strategies.

Is ADHD a Risk Factor for Psychoactive Substance Use Disorders? Findings From a Four-Year Prospective Follow-up Study

Contradicting some of the aforementioned studies, a four-year follow up study was done to evaluate whether or not ADHD is a risk factor for substance use disorders in relation to psychiatric problems, family history, and adversity.6 Using different assessments, researchers examined 140 subjects with ADHD and 120 normal control subjects four years after their substance use disorder diagnosis.

The results show no difference between the rates of alcohol or drug abuse between the ADHD and control subjects. Conduct and bipolar disorders were able to predict substance use, independent of whether or not ADHD was a factor. Family history and antisocial disorders were also linked to the control group, but less in the ADHD group. Finally a family history of ADHD was not considered to be a risk for the development of a substance use disorder.

Mediating Factors to Consider

One might see potential correlations between ADHD and substance use disorders. However, this is not exclusively conclusive in any of the studies. Furthermore, it is important to acknowledge the lack of consideration in relation to a person's childhood, family life, school life, and other socio-behavioural factors. Prior to suggesting a causal link to ADHD for an increased risk of substance use, abuse, and dependency, it is important to take into consideration all mediating circumstances that could influence a person's decisions.

ADHD + Behaviour Disorder and/or Substance Abuse => Substance Dependence

If a person has ADHD, there is a potential that they also experience other behaviour disorders such anxiety disorders (including panic attacks, PTSD, and general anxiety), obsessive compulsive disorder, bipolar disorder, or dissociative disorders. Behavioural disorders often appear in children and can progress into adulthood. It is generally believed there is no single root cause. Rather, biological, physical, and environmental issues are thought to work simultaneously alongside risk factors such as maternal rejection, poverty, abuse, and so forth.

On the other hand, a person with a diagnosis of ADHD could turn to substance abuse as a means of coping with their symptoms of the ADHD. It is also plausible for both behavioural disorders and the substance abuse to occur at the same time. With either health issue, if left undiagnosed and untreated, there is a potential for the development of a substance use disorder.

It is also important to take note of the vicious cycles of reinforcement including the following additional compounding possibilities.

Substance Dependence + Behaviour Disorder and/or ADHD + Substance Misuse => Substance Dependence

Some adults, regardless of their gender or age, may be dependent on a substance and aggravate underlying symptoms of a behavioural disorder or ADHD. If the individual seeks out treatment for the substance abuse disorder, and is unaware of the behavioural disorder or ADHD, there is a chance that they will struggle with their sobriety because of the symptoms of the co morbid disorders. Eventually substance misuse, abuse, and dependence could arise; thus, creating a revolving circle of reinforcing destructors.

Substance Misuse + Behaviour Disorder and/or ADHD => Substance Dependence

Finally, substance misuse combined with the symptoms depression, anxiety, PTSD, OCD, bipolar disorder, ADHD, and so forth can quickly turn into a substance use disorder. The reasons for the individual using drugs or alcohol may be inherently unique, but in some way related or linked to the behavioural disorder. If undiagnosed, a repetitive cycle can ensue.

What is important to take away from here is that it is not true and accurate to say that a person with ADHD will likely experience a substance use disorder, and a person with a substance use disorder will not always have ADHD or a behavioural disorder. However, there is a probable correlation between the a behavioural and substance use disorder which is why it's prudent to acknowledge the signs and effects of a comorbid disorder. When this is diagnosed, the patient can be treated for all relevant issues.

Conclusion: Correlation between ADHD and Substance Abuse in the Research Literature

No direct, causal connection between ADHD and substance use disorders has been established. However, there is an increased likelihood of behaviour disorders with ADHD. These behavioural or mental health issues can lead towards substance misuse, which can then turn into a substance use disorder.