ADHD Comorbidity

Attention deficit hyperactivity disorder (ADHD) can present many challenges on its own, yet many individuals with ADHD also have comorbid disorders (termed ADHD comorbidity), which makes diagnosis and treatment even more complex.

Therefore, it’s important to identify and understand ADHD comorbidity in order to help address unique symptoms for each individual and, in turn, improve overall life quality.

What is ADHD Comorbidity?

ADHD comorbidity is a term referring to mental health disorders that exist alongside ADHD. At least 60% of all individuals with ADHD have at least one comorbid condition, such as various learning disorders, mood disorders, and anxiety disorders. ^[1]

ADHD comorbidities can lead to several issues not necessarily seen in ADHD by itself. For one, symptoms of other mental disorders may overlap with ADHD, which may lead to problems with accurate diagnosis and recognition of the condition, especially for adults. ^[2]

In addition, having existing mental health conditions alongside ADHD can cause significant disruptions to one’s life, with negative effects on school, work, interpersonal relationships, sleep, and overall health.

Thus, it’s vital to accurately examine and diagnose ADHD comorbidity. Doing so can generate more specific and individualized treatment plans to help manage and reduce symptoms.

Common Comorbid Conditions with ADHD

There are several common comorbidities with ADHD, especially learning disorders, mood and anxiety disorders, and personality disorders. Below is an overview explaining these common comorbid conditions and their prevalence.

Autism Spectrum Disorder

Autism spectrum disorder (ASD) has a high comorbidity rate with ADHD of around 40%. Thus, it is one of the most common ADHD comorbidities out there. ^[1]

ASD is a neurodevelopmental disorder with several key characteristics, such as problems with social interaction and communication, repetitive or restricted interests, hypersensitivity, and trouble with emotional regulation. Individuals with ASD may have trouble maintaining eye contact, exhibit repetitive or restricted behaviors, and have a strong need for routine or sameness.

Mood Disorders

Major depressive disorder, bipolar disorder, and dysthymia are mood disorders commonly seen in individuals with ADHD. Nearly 40% of adults with ADHD experience some sort of mood disorder, while the rates of depression alone in children with ADHD range from 12 to 50 percent. ^{[1] [2]}

Individuals with depression or dysthymia often experience a multitude of symptoms, such as lack of pleasure, little to no interest in activities, poor sleep, suicidal thoughts, fatigue, changes in appetite, and irritability. ^[3]

Bipolar disorder is characterized by extreme changes in emotions and behaviors. During manic episodes, individuals are very energetic, need little sleep, and have feelings of euphoria. Yet during depressive episodes, the common symptoms are intense sadness, hopelessness, little energy, and lack of pleasure. ^[3]

Anxiety Disorders

Anxiety disorders are also very common in ADHD, with estimated rates ranging from approximately 15 to 50%. ^{[2] [3]}

In adults with ADHD, rates of social anxiety disorder (SAD), generalized anxiety disorder (GAD), post-traumatic stress disorder (PTSD), specific phobia, panic disorder, agoraphobia, and obsessive-compulsive disorder (OCD), are also significantly higher than in the general population. ^[2]

While all of these anxiety disorders have distinct features, they share several overlapping characteristics, such as excessive worry, fear, anxiety, trouble sleeping, and physical sensations, such as rapid heart rate, shaking, and sweating. ^[4]

Learning Disorders

Learning disorders are highly prevalent in ADHD, with rates ranging from 10 to 92%. More specific estimates in children suggest learning disability rates of 31 to 45%, with writing disabilities in particular at the highest incidence ^{[1] [2]}.

Learning disorders are neurodevelopmental disorders that cause difficulty with various skills, such as reading, writing, spelling, calculation, mathematical reasoning. Thus, this disorder is often identified in children who show deficits compared to their peers. ^[5]

Behavioral Disorders

Rates of behavioral disorders, such as oppositional defiant disorder (ODD) and conduct disorder (CD), are also higher in ADHD than the general population. Among these, ODD is the most common, with rates as high as 30 to 50% of all individuals with ADHD. ^[1]

Common characteristics of ODD are anger, defiant behaviors towards authority, disobedience, and frequent arguing and intense displays of emotion. ^[6]

CD involves impulsivity, failure to follow or obey rules, as well as a variety of aggressive, violent, and destructive behaviors, such as destroying property, stealing, or hurting others. ^[6]

Substance Use Disorders

Substance use disorders (SUDs) are two to three times as common in individuals with ADHD compared to the general population. Some of the most commonly abused substances are alcohol, nicotine, cannabis, and cocaine. ^{[2] [3]}

Individuals with SUD have an inability to control their substance use despite harmful consequences. This often involves intense cravings, personality changes, and behavioral changes. In addition, they develop a tolerance over time, which can lead to withdrawal symptoms once substance use is stopped. ^[7]

ADHD Symptoms vs. Symptoms of Comorbid Conditions

In order to effectively diagnose and treat individuals, it’s important to differentiate between ADHD symptoms vs symptoms of comorbid conditions. This is particularly important since many symptoms of comorbid conditions involve one or more of the primary symptoms of ADHD, which are inattention, hyperactivity, and impulsivity. ^[8]

In order to do this, a comprehensive professional evaluation is needed. This involves medical history, psychological evaluation, a physical exam, and possibly lab tests.

Ultimately, differentiation is done using the guidelines in the American Psychiatric Association’s Diagnostic and Statistical Manual of Mental Disorders, 5th Edition, Text Revision (DSM-5-TR). Below is a general overview of some of those differentiations based on those guidelines to provide initial insight. ^[9]

ADHD vs ASD

Individuals with ADHD and ASD can have many of the same issues, such as trouble concentrating, impulsivity, and various social/relationship issues.

However, individuals with ADHD have issues focusing due to their short attention span, whereas in ASD, trouble focusing may stem more from disinterest in the subject or from trouble switching from one task to the next. In fact, people with ASD often exert high levels of focus and concentration if it is something that interests them. ^{[8] [9]}

Other key characteristics of ASD that are not features of ADHD include eccentric behaviors and lack of social-emotional reciprocity. ^[9]

ADHD vs Depressive Disorders

ADHD and depressive disorders may share similar characteristics at times, such as trouble concentrating and poor sleep. However, with depression, these characteristics are due to depression itself, whereas in ADHD, these result from a short attention span and hyperactivity.

In addition, key factors that distinguish depression from ADHD are depressed mood, anhedonia, low energy, and suicide-related issues. While ADHD can cause mood changes, especially due to the obstacles it causes in navigating everyday life, this is usually only temporary, compared to the sustained low mood in clinical depression. ^[9]

ADHD vs Bipolar Disorder

ADHD often can cause trouble sleeping, hyperactivity, and impulsivity, which may be mistaken for BD. However, BD can be differentiated from ADHD based on the presence of alternating manic and depressive episodes, drastic mood changes, and significant changes in sleep patterns. ^[9]

ADHD vs Anxiety Disorders

Anxiety disorders and ADHD may also have some seemingly overlapping symptoms, such as poor focus, agitation, and sleep issues. However, anxiety is unique from ADHD in that it doesn’t involve impulsivity as a primary feature, and it also involves greater physical symptoms and the presence of worry or rumination, which aren’t usually seen with ADHD. ^[4]

Importantly, the challenges presented by ADHD certainly can increase anxiety and related symptoms. However, true clinical anxiety can be identified from intense worry that lasts for several months or more. ^[9]

ADHD vs Learning Disorders

Lack of concentration and attention in ADHD may result in poor grades and performance, which can sometimes be confused with a learning disorder. While ADHD and learning disorders certainly coexist (and often at high rates), there are distinguishing features.

One of the main things to understand is that inattention and trouble concentrating for individuals with learning disorders often stems from a lack of comprehension and ability, whereas in ADHD, these factors stem from the nature of the disorder itself. ^[8][9]

ADHD vs Behavioral Disorders

ODD and CD are behavioral disorders that occur at high rates alongside ADHD, but again, there are distinguishing features important to recognize. Inattention and impulsivity are common overlapping symptoms between ADHD and behavioral disorders, although their causes are different.

For example, inattention in ADHD is caused by the disorder itself. On the other hand, individuals with ODD choose to not pay attention or stay on task due to their defiant behavior. ODD also has many symptoms not primary to ADHD, including temper flares and being vindictive. ^[9]

Also, CD and ADHD can both involve impulsive actions. However, with CD, these actions are aggressive, destructive, violent, and often involve breaking rules and/or laws. ^[9]

How Does Comorbidity Affect ADHD Treatment?

Comorbid ADHD ultimately requires a more complex treatment approach compared to dealing with ADHD alone. This is due to several factors, such as medication management and condition prioritizing.

Regarding medication management, some medications that may be beneficial for ADHD may interact with medications that are beneficial for comorbid conditions. For example, stimulants often used to treat ADHD may not be well tolerated in individuals with anxiety disorders or ASD. Thus, it’s important to only treat patients with medications that effectively address all issues with little to no interactions or side effects. ^[9]

Also of concern is condition prioritizing. In other words, when someone has ADHD and comorbid conditions, professionals should determine which disorder should be prioritized, or if multiple conditions can be treated with the same priority and effectiveness simultaneously.

In individuals with BPD and SUD, these should always be treated first, whereas ODD and CD can be treated alongside ADHD simultaneously. For other disorders, such as anxiety and mood disorders, whatever is the most impairing disorders should be treated first. In general, if there is confusion on what to do, the best way to go about it is to treat the most serious or debilitating condition first and continue on from there. ^{[3] [8]}

Treatment for Comorbid ADHD

While treatment for comorbid ADHD may seem daunting at first, the reality is that a lot of the same approaches that are used for other mental disorders can be used in these situations as well. Some of the effective treatments that may come into play when treating comorbid ADHD include medication, therapy, and lifestyle changes.

Medication

Medications can be useful for ADHD and various comorbid conditions. Of course, the exact combination depends on one’s specific diagnoses. Listed below are common medications used to treat ADHD and comorbid conditions: ^[10]

• ADHD: Stimulants, cognitive-enhancers
• Autism Spectrum Disorder: Antipsychotics, antidepressants,
• Anxiety Disorders: SSRIs, benzodiazepines
• Mood Disorders: SSRIs and other antidepressants,
• Bipolar Disorders: Antidepressants, antipsychotics, mood stabilizers

Working with a mental health professional can lead to the most appropriate medication combination to increase the likelihood of benefits, while minimizing the risk of side effects and interactions.

Therapy

Therapy and counseling may also be effective for comorbid ADHD, especially when in the form of cognitive-behavioral therapy (CBT). CBT is a type of therapy that aims to identify negative thought patterns and behaviors, in turn changing these into healthier, more effective ones.

CBT offers many potential benefits for anxiety disorders, mood disorders, behavioral disorders, and ADHD itself. And since CBT can be adapted to anyone’s individual needs and issues, it is a very versatile and effective option. ^[9]

Lifestyle Changes

Comorbid ADHD can cause a lot of stress, which negatively impacts overall health. Therefore, adopting healthy lifestyle habits, such as regular exercise, adequate sleep, and a healthy diet, can help in managing symptoms. Of course, the nature of some of these conditions makes management more difficult, but do the best you can.

In addition, it is beneficial to implement stress-management techniques, such as meditation, deep breathing, and journaling. Joining a self-help group may also help to lower stress and provide greater feelings of confidence and connection.

Living with Comorbid ADHD

ADHD comorbidity presents additional challenges compared to ADHD by itself, which can already be difficult enough to manage. Fortunately, several coping strategies and daily habits can help offset these challenges and foster improved mental health and overall well-being.

First, it’s important to implement a healthy mindset and self-compassion. Many individuals with ADHD and other mental disorders are often judged negatively, often with the use of labels such as “lazy”, “weird”, etc. It’s important to challenge these judgments, while also practicing self-compassion. If you have comorbid ADHD, understand that this is a very real disorder with legitimate concerns. Try to be easy on yourself as you navigate this condition. Celebrate small progress and avoid going down a spiral of negative thinking.

Organization and planning are other helpful things to implement. ADHD comorbidity often makes navigating daily life more stressful than for others. To help reduce some of this stress, try to organize your environment, plan out your days, and create a daily routine to follow.

Lastly, aim to practice as many healthy habits as you can, such as regular exercise, a healthy diet, proper sleep, and regular socialization. These all promote better overall health and wellness and can provide a sense of empowerment and control in situations where this otherwise may be lacking.