Understanding The Three Different Types Of ADHD

Medically reviewed by Paige Henry, LMSW, J.D.
Updated April 16, 2024by BetterHelp Editorial Team

Many people have moments when they have trouble focusing, lose track of time, or act impulsively, but an individual with attention deficit hyperactivity disorder (ADHD), previously known as attention deficit disorder, experiences these symptoms so consistently and severely that it substantially interferes with their life. More than simple forgetfulness or trouble concentrating, ADHD is a chronic, neurobiological condition that can last a lifetime and can have profound impacts if undiagnosed.

Many people think of ADHD as a single disorder, but there are three distinct types: inattentive, hyperactive-impulsive, and combined type ADHD. Each type is diagnosed according to a specific configuration of mental and behavioral symptoms and based on the degree to which the symptoms cause impairment.

Historically, there was a common misconception that people outgrew ADHD, but now we know that in over 60% of cases, symptoms continue after the age of 18. However, symptoms may display differently in adulthood than in childhood. For example, difficulty controlling impulses may shift from speaking out in class toward impulsive decision-making. Or daydreaming in school may change to difficulty paying attention in meetings. Additionally, those with high-functioning ADHD may struggle to recognize common symptoms.

Understanding ADHD subtypes can help you better understand and manage ADHD symptoms.

Are ADHD symptoms making life difficult?

Hyperactive-impulsive ADHD

This type of ADHD presents with a lot of the "classic" hyperactive and impulsive symptoms that people associate with the condition such as risk-taking, fidgeting, and an inability to sit still. Sometimes, what started as a compulsive need to move your body as a child may turn inward and become an inability to stop your racing thoughts. As an adult, impulsive symptoms may be most noticeable. Impulsive type ADHD could present as buying something you can't afford or speaking unprofessionally with a supervisor, for example. 

Hyperactive and impulsive ADHD is more frequently diagnosed in males than in females. If you have this type of ADHD, you may have difficulty thinking about the consequences of your actions. This can lead to difficulties with work, relationships, and other areas of your life. An individual with this subtype may frequently interrupt others during a conversation, take dangerous risks, and seek stimulation in unhealthy ways, for example.

Since hyperactive and impulsive behaviors tend to be more obvious in childhood, this subtype of ADHD is often caught early. However, that's not always the case, especially if the individual exhibits mild hyperactive behavior.

Signs of hyperactive-impulsive ADHD include:

  • Trouble sitting still for long periods; fidgets a lot
  • Fast speech; frequently interrupts others
  • Doesn't appear to consider the consequences of their actions
  • Acts impulsively, including driving, spending, and relationships
  • Chronic impatience; difficulty waiting
  • Feelings of restlessness 

Inattentive ADHD

An individual with inattentive type ADHD may have difficulty maintaining focus on routine tasks or conversation, be frequently distracted, and make mistakes due to a lack of attention. Inattentive ADHD may go undiagnosed for years since most children with inattentive behavior symptoms don't disrupt the classroom. In adulthood, this subtype can manifest in various ways. For example, you may have difficulty completing work duties, meeting deadlines, or focusing on individual tasks. You probably won't experience many impulsive behavior or hyperactivity symptoms, but the condition can still create unnecessary stumbling blocks.

Inattentive ADHD used to be referred to as attention deficit disorder (ADD), although the term is no longer used. Primarily, inattentive ADHD is thought to be the least common type of ADHD and is slightly more common in females.

Signs of inattentive ADHD include:

  • Difficulty following instructions and finishing tasks
  • Trouble concentrating; forgetfulness
  • Gets distracted easily
  • Chronic boredom
  • Occasional extreme focus ("hyperfocus") on a stimulating task
  • Difficulty following a conversation
  • Frequently losing items

ADHD combined type

The third and most common type of ADHD is ADHD combined type. As the name suggests, this form of ADHD includes symptoms from both the inattentive and hyperactive-impulsive groups. To be diagnosed with combined ADHD, you need to have a combination of at least five of the symptoms from either category. You may not display every symptom, but there should be sufficient evidence of both types.


Other ways ADHD can vary

ADHD exists on a spectrum, and symptoms can present differently from person to person. The presentation also depends on the coping mechanisms you've developed to manage your issues prior to diagnosis. Symptoms can also change as you get older. You may start with hyperactive-inattentive ADHD only to develop combined type in adulthood, for instance.

Mild ADHD might not require intensive treatment. However, as with many medical conditions, people with ADHD may benefit from a combination of behavior therapy, support groups, and medication.

What causes attention deficit hyperactivity disorder (ADHD)?

People with ADHD have lower levels of the neurotransmitter dopamine in the area of the brain responsible for impulse control, attention, and other so-called "executive functions." This causes difficulty controlling behavior, comprehending long-term consequences, stifling impulses, and sustaining attention. Brain imaging has shown that the brains of people with ADHD aren't always "on, " and it takes a higher level of stimulation in this area to get them there. This is why stimulant medication can be effective.

While a great deal of research has been performed to discover the cause of ADHD, mostly in pediatric patients, we're still not sure of the exact cause. Different types of ADHD do not appear to have different causes. ADHD has been shown to have a strong genetic component, and it's not uncommon for adults to seek an evaluation after their children receive a diagnosis. Exposure to alcohol, tobacco, and illegal substances during pregnancy may increase the child’s chance of developing ADHD.

If you are struggling with substance use, contact the SAMHSA National Helpline at (800) 662-4357 to receive support and resources. Support is available 24/7.

Video games, excessive TV, and other sources of high stimulation have not been shown to cause ADHD. While many people used to believe excessive consumption of sugar caused ADHD, this is also not the case. A link between exposure to pesticides has been suggested as a cause for increased rates of ADHD being seen in recent years, but more research is needed to make a definitive conclusion.

How do you diagnose ADHD?

As we continue to learn about this unique condition, more and more adults are getting their suspected ADHD diagnosed. Whether it's at the advice of friends and family, after a problem such as a car accident, or just being fed up with late appointments and disorganization, something drives the individual to seek an ADHD diagnosis.

ADHD is diagnosed using the latest version of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5), the manual used as the official resource for determining mental disorders. Adults must regularly display five or more of the symptoms outlined in the DSM under one of the subtypes to be formally diagnosed. Moreover, evidence of these symptoms should be present before age 12.

A formal diagnosis of ADHD is made by a psychiatrist, psychologist, or another health professional with experience in diagnosing developmental disorders. Complete diagnosis may take several appointments, depending on the provider. They will perform an in-depth interview with you, asking questions about your symptoms and how they affect you to get a detailed history of symptoms.

Not everyone who displays hyperactivity or inattentiveness has ADHD, of course. The diagnosis depends on the length of time the symptoms have been present and the degree to which the individual is negatively affected. Other conditions that can mimic ADHD, such as depression or OCD, need to be ruled out as well. These conditions can coexist with ADHD, and if that is the case, they may need separate treatment.

Are ADHD symptoms making life difficult?

Treatments for all types

If you are diagnosed with any type of ADHD, many effective treatments are available to help you manage the condition. The better you understand your particular type of ADHD, the better you can customize your treatment.

Talk therapy

For children and teens, behavioral interventions such as therapy are usually attempted before medication to manage symptoms and improve your child’s life. Most adults with ADHD also benefit from working with a therapist to help them develop strategies for managing their symptoms. Cognitive behavioral therapy (CBT) is the most researched form of talk therapy for ADHD and involves recognizing and changing negative thought patterns.

Medication options

Different types of ADHD may respond better to one medication than another. Stimulant medication is approved to treat ADHD in adults as well as children. Stimulants work by increasing the amount of dopamine and norepinephrine in certain parts of the brain that can increase focus, improve working memory, and direct impulse control.

Non-stimulant medication is also available for those who don't respond well to stimulants. This medication must be taken for several weeks before the desired effect is achieved.

Should you try medication?

The choice to try medication is always up to the individual. Stimulants can be effective in up to 80% of cases, and the risk of side effects is quite low. However, many people choose to forgo medication. It's up to your personal preference. There are many lifestyle changes and behavioral modifications that can help you effectively manage your adult ADHD with or without medication.

Working with a therapist

Some people with ADHD may experience difficulties managing in-person therapy appointments. After all, symptoms of the condition like disorganization and forgetfulness can make it challenging to show up to these office visits on time.  Online therapy is another option. Many people with ADHD and other mental health conditions find internet-based treatments to be more convenient. With BetterHelp, for instance, you can connect with a therapist at a time that works for you from the comfort of your home.  

This type of treatment protocol has been found to be effective in treating ADHD as well. A 2022 meta-study evaluated the effects of online therapy on individuals diagnosed with the condition. The outcome indicated a positive effect on both attention deficit and social function. 


A therapist can be helpful when it comes to managing your condition, no matter which type of ADHD you have. Many people find an ADHD diagnosis to be reassuring and validate the struggles they've experienced their whole lives, but it's normal to have mixed feelings, too. Online therapy is a convenient, affordable way to connect with a therapist who can help you make the most of your ADHD treatment.

Gain a better understanding of ADHD
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