Understanding ADHD-PI: Predominantly Inattentive ADHD

Attention-deficit/hyperactivity disorder (ADHD) is a neurological condition that can cause symptoms such as inattentiveness and hyperactivity. The Diagnostic and Statistical Manual of Mental Disorders (DSM-5) lists three ADHD presentations (also referred to as ADHD subtypes): the hyperactive-impulsive type (ADHD-PH), the predominantly inattentive type (ADHD-PI), and the combined type (a mix of both).

Attention deficit hyperactivity disorder predominantly inattentive (ADHD-PI) is a form of ADHD that can affect behavior, executive functioning skills, concentration, and the ability to focus. ADHD-PI lacks the hyperactive symptoms of the other two types of ADHD. In diagnosing the condition, clinicians look for signs of difficulty sustaining attention. In the past, the condition may have been referred to as an “attention deficit disorder,” or ADD.*

*Please note that the term “ADD” is no longer used by mental health professionals. BetterHelp strives to use current terminology to accurately discuss mental health. Throughout the rest of the article, we will use the updated term “ADHD” to explore this topic.

As a widespread condition often diagnosed in children under 11, about 10% of American children have received an ADHD diagnosis, with 45-75% being diagnosed with the predominantly inattentive (PI) type. Adults can also have ADHD, and often children with ADHD carry similar symptoms and patterns into adulthood.

Causes of ADHD

While researchers are still not aware of the direct causes of ADHD and ADHD-PI, specific biological issues are often thought to be a cause. Many believe environmental factors can contribute to the severity of ADHD symptoms over time as well. Even though experts do not know the exact cause of ADHD, several risk factors may affect its development.

For example, while we are lacking research that includes other genders, research shows men are four times more likely to have ADHD than women. Genetics can also play a role—parents with ADHD can pass the condition to children, whether behaviorally or hereditarily. The possibility of having ADHD increases if a family has the disorder. The heritability of ADHD is approximately 77-88%, comparable to bipolar disorder, schizophrenia, and autism.

Other risk factors could include:

• Exposure to heavy metals or other toxins

• Premature birth

• Low birth weight

• Other mental health diagnoses

• Substance use during pregnancy (including alcohol, drugs, and smoking)

Symptoms of ADHD

ADHD can present in many ways. Although diagnosis can be common in childhood, adults can also experience symptoms. According to the National Institute of Mental Health adults with ADHD may experience the following symptoms:

• Difficulty working quietly by yourself

• Interrupting others

• Trouble concentrating and maintaining sustained attention

• Difficulty paying attention

• Problems with sitting still

• Challenges with organizational skills

• Fidgeting, moving hands and feet, or rocking

• Difficulty following orders or understanding authority

• Disruptive behavior 

• Easily distracted or forgetful behavior

• Unfinished schoolwork or failure to complete tasks

• Frequently making careless mistakes

• Learning difficulties

• Procrastination

• Impulsivity

• Losing or misplacing items

• Making mistakes

• Restlessness

• Rushed speech

• Hyperfocus on tasks you are enthusiastic about

• Executive dysfunction (difficulty with filling out forms, cleaning, chores, structure, and work or school tasks)

Types of ADHD

There are three types of ADHD. These include the hyperactive-impulsive type, predominantly inattentive type, and combined type. While each type may have some common symptoms, the diagnostic criteria for each are slightly different.

Hyperactive-impulsive type

Hyperactive-Impulsive ADHD, also known as ADHD-PH or Hyperactive ADHD, is commonly diagnosed in children and less so in adults. It can present as a person who struggles with sitting still, has difficulty understanding when to enter and exit a conversation, and fidgets often.

In adults, these hyperactive-impulsive symptoms can show up as difficulty staying focused on one task, impulsive symptoms and behaviors, and a need for constant brain stimulation. They may struggle with feeling highly energetic or restless.

Predominantly inattentive ADHD

Predominantly inattentive ADHD (ADHD-PI) also called Primarily Inattentive ADHD or ADHD inattentive type, can cause distraction and short attention spans. Those diagnosed with ADHD-PI may lose things often and feel unorganized. They can lose focus quickly and may spend time daydreaming. They may be a person that often makes careless mistakes. Peers may mistakenly label an individual as lazy or unmotivated.

Combination ADHD

Those with combination ADHD, also called ADHD combined type or ADHD C group, have some symptoms from ADHD-PI and ADHD-PH types. They may show signs of hyperactivity and inattentive behaviors simultaneously or switch from one to the other. They may have also struggled with symptoms of hyperactivity as a child related to ADHD-PH but started to find their ADHD-PI symptoms to increase with age.

What is ADHD-PI?

ADHD-PI is predominantly inattentive attention-deficit/hyperactivity disorder. It is currently considered the second most common type of Attention Deficit Hyperactivity Disorder (ADHD) in adults, with 31% of adults with ADHD having this type.

Many people diagnosed with ADHD-PI report experiencing a short attention span, forgetfulness, and procrastination issues. In some inattentive children, it can cause fatigue, lethargy, or sluggishness.

Many adults with ADHD-PI type also experience the following inattentive symptoms:

• Obsessive-compulsive tendencies

• Hoarding

• Difficulty learning new things

• Processing information slowly

• Difficulty finding misplaced items

• Forgetting instructions, obligations, or appointments

• Seeming to daydream or space out

• Ignoring others by accident

• A lack of attention when having a conversation

• Feeling distracted or “out of it”

• Fatigue

• Having to reschedule dates or other plans because you forgot

• Difficulty recalling a conversation

• Hesitation when responding to others

• Feeling bored easily

• Missing key details

• Feeling overwhelmed by tasks

What ADHD-PI is not

In older children or adults, ADHD-PI may be mistaken as anxiety or a mood disorder. While it may have similarities to these two, such as trouble concentrating on daily tasks, or frequently feeling fatigued, it is a completely separate condition.

When distinguishing between hyperactive, combined, and inattentive types of ADHD, clinicians may rule out hyperactive and impulsivity symptoms and impulsivity such as:

• Frequent movements

• Fidgeting, tapping, or bouncing

• Interrupting conversations with others

• A loud voice

• Repeating of phrases

• Difficulty focusing without help

• Difficulty in relationships

• Difficulty waiting his or her turn

• Lack of impulse control

At times, patients with ADHD-PI may seem withdrawn, anxious, depressed, or anti-social. They may keep to themselves when unsure about a situation. This type of ADHD can often look like social anxiety or depression. It can be helpful to talk to a mental health professional about the potential of being ADHD diagnosed when you’re unsure.

Keep in mind that ADHD can be comorbid with (occurring at the same time as) anxiety or depression diagnoses. Many adults with ADHD also experience other mental health conditions.

Diagnosing ADHD-PI

Because ADHD-PI can often go undiagnosed, it may be untreated from childhood until adulthood. By the time you pursue a diagnosis, you may feel that your symptoms have become a part of your identity. If you relate to any of the symptoms mentioned above, a licensed professional can help you better understand this condition and diagnosis.

Many adults do not consider ADHD a valid diagnosis for themselves because of the misconception that ADHD only includes hyperactive symptoms. However, ADHD-PI is a genuine condition that is often misrepresented.

Connect with your doctor

When looking into an ADHD diagnosis, consult with your primary caregiver or physician first. They may check for other medical conditions that could be contributing to certain physical symptoms. They can also help with pharmacological treatment.

One of the tests that may help your doctor in diagnosing ADHD is a brain scan.  Several studies suggest that ADHD may create certain differences in the brain and nervous system in those with the condition. Brain MRIs and CT scans help the doctor look at the inside of your brain with neuroimaging. They may look for activity in the areas of the brain that control attention span, and you may be asked to complete exercises or activities during the exam. The scan should be painless, and it is non-invasive. You can often complete it within an hour, similar to an X-Ray.

Speak to a mental health expert

Beyond physical symptoms, there are also licensed psychiatrists and mental health professionals who can work with you to get a diagnosis.

A mental health provider may also help you determine whether you need further testing for ADHD, such as cognitive, memory, and intelligence tests. Overall, there are many experts in this field who can provide support, guidance, and resources related to living with ADHD. The same is true for ADHD-PI children.

Treatments for ADHD-PI

The most common methods used to treat ADHD include medication and therapy. There are two categories of ADHD medication: Stimulants and non-stimulants. Both classes of medications help manage ADHD symptoms. Stimulants are the most commonly prescribed medication because they are effective in 70% of adults and 70 to 80% of children. Non-stimulants are recommended when stimulants aren’t effective. 

The goal of therapy for ADHD is to help patients create desirable and positive thought and behavior patterns. Speaking to a professional online or in-person can often help you navigate daily tasks or obstacles you may encounter with ADHD.

For example, in a study published in the Journal of Attention Disorders, researchers evaluated the effectiveness of online cognitive-behavioral therapy (CBT) in treating adults with ADHD. They found that participants experienced a significant reduction in symptoms when participating in online therapy, with positive results sustained at a six-month follow-up. These findings are similar to those done with younger study groups, outlining the positive effects of online CBT. Cognitive-behavioral online therapy is a widely accepted form of treatment that works by helping individuals reframe negative thought patterns that may be underlying certain behaviors or feelings, such as ADHD-related difficulties with concentration or memory.

Online therapy platforms like BetterHelp offer a variety of options for treatment, including video calling, phone calls, and in-app messaging. You can also attend therapy from home, which many adults find comforting during treatment.