Attention deficit disorder (Inattentive ADHD)

What is attention deficit disorder?

Attention-deficit/hyperactivity disorder (ADHD) is a neurodevelopmental condition that presents with symptoms of inattention, hyperactivity, and impulsivity. Attention deficit disorder (ADD) is a term previously used to refer to ADHD that presents primarily with symptoms of inattention, with an absence of hyperactive and impulsive behaviors ^[1][2].

Recent adaptations to diagnostic criteria have changed to include different subtypes or presentations of ADHD. As such, ADD is now referred to as ADHD with predominantly inattentive presentation, or inattentive ADHD ^[2].

Inattentive ADHD symptoms

Symptoms of inattentive ADHD may differ from person to person, but typically include ^[3][4]:

• Regularly making mistakes or errors in work
• Becoming distracted easily, either by own thoughts or by external stimuli
• Often losing things or struggling to find things
• Difficulty remembering instructions and details
• Inability to remain focused on one task for a prolonged period
• Often avoiding beginning a task that will take a long time or requires focus
• Struggling to organize activities, such as collecting required items or keeping things tidy and in order
• Poor time management and difficulty meeting deadlines
• Often moving on to the next activity before finishing the last
• Difficulty listening to others; mind appears to be elsewhere when others are talking
• Emotional dysregulation, such as mood swings, low mood, anger, anxiety, and easily frustrated

What causes inattentive ADHD?

Currently, it is believed that inattentive ADHD and hyperactive-impulsive ADHD are caused by a combination of different factors. The different presentations of ADHD can co-occur and change throughout the lifetime and each presentation may share contributing factors. However, new research is constantly investigating the causes to develop a better understanding ^[5].

Genetics

ADHD has a highly genetic disorder and often runs in families. As such, there is a significantly high likelihood that a person with ADHD will have a child with ADHD. Additionally, subtypes of ADHD do not alter the possibility of heritability. Inattentive, hyperactive-impulsive, and combined ADHD presentations can occur within the same family ^[4][6].

Brain

Studies have found differences in the brains of people with ADHD compared to those without. This includes differences in the volume and activity of specific brain areas and the levels and activity of certain neurotransmitters, such as dopamine and norepinephrine ^[7][8].

Pregnancy complications

Research suggests that complications during pregnancy and childbirth can contribute to the risk of ADHD. For example, low birth weight, preterm delivery, and exposure to tobacco and substances during pregnancy are all thought to increase the likelihood of the child having ADHD. However, this link may also be related to other factors ^[6][7].

Other risk factors

Some research suggests that individuals with epilepsy or who have incurred a traumatic head injury may be at an increased risk of ADHD ^[4][6].

Inattentive ADHD diagnosis

Diagnosing inattentive type ADHD is considered to be more challenging than diagnosing hyperactive-impulsive ADHD. This is because inattentive ADHD causes internalized symptoms that may go unnoticed for some time. As such, many cases of inattentive ADHD are not diagnosed until later in life when the impact of symptoms becomes more evident ^[3].

For a child or adult to seek a diagnosis of inattentive ADHD, it is necessary to be assessed by a specialized professional, such as a pediatrician, psychiatrist, or other trained mental health professional ^[4].

The professional will assess the individual using structured interviews and questionnaires that help to ascertain information about the presenting symptoms. Assessing children will also involve gathering information from parents, including development, functioning, and behavior at home ^[1][6].

Similarly, gathering information from the child’s school and teachers about academic functioning and behavior in the classroom and with peers can be helpful ^[8]. The mental health professional will also gather information about individual and family mental and physical health history.

It is common for ADHD to co-occur with other conditions, such as learning disorders, anxiety, depression, autism spectrum disorder, and obsessive-compulsive disorder (OCD). As such, questions relating to the presence of these conditions will also be asked ^[4][8].

The clinician will utilize the diagnostic criteria for ADHD in the Diagnostic and Statistical Manual of Mental Disorders (DSM-5) to formulate their diagnosis. Criteria for ADHD with predominantly inattentive presentation state that six or more of the following symptoms must be present for at least six months ^[2]:

• Making careless mistakes and poor attention to detail
• Difficulty retaining focus
• Difficulty listening to others
• Difficulty completing tasks and following instructions
• Trouble organizing activities, items, and time
• Avoidance of tasks that require prolonged focus
• Regularly losing items required for tasks
• Easily distracted
• Regularly forgetful with dailyactivities and tasks

Additionally, the following must be true:

• Symptoms cause significant impairment in functioning
• Symptoms have emerged before the age of 12
• Symptoms occur in more than one setting, such as school, home, and social activities
• Symptoms are not due to another condition

The severity of these symptoms can also be determined as mild, moderate, or severe ^[2].

The individual will also be assessed for symptoms of hyperactivity and impulsivity using DSM-5 criteria. They can then be diagnosed with ADHD with a predominantly inattentive presentation, ADHD with a predominantly hyperactive and impulsive presentation, or combined ADHD if the criteria for both presentations are met ^[2][5].

Inattentive ADHD treatment

Inattentive ADHD is often treated with medication and therapeutic interventions.

Medication

Current research and evidence suggest that people with different ADHD presentations respond similarly to medications. As such, there is no difference in the medications prescribed to individuals with inattentive ADHD and hyperactive-impulsive ADHD, although lower doses may be required to treat inattentive ADHD effectively ^[3].

This includes ^[7][8]:

• Stimulants: Stimulants, such as methylphenidate and dextroamphetamine, are commonly used medications for ADHD. Studies show that stimulants are effective for both children and adults with ADHD and can improve focus and functioning. However, there are concerns about the long-term use of stimulants in children due to the increased risk of side effects.
• Non-stimulants: Other medications, such as atomoxetine and clonidine, can also treat ADHD in children and adults. Non-stimulants have been found to be slightly less effective at managing symptoms than stimulants but may be better tolerated and cause fewer side effects. They can also be used alongside stimulant medications to help manage comorbid conditions and symptoms.

Therapy

Behavioral interventions can help manage symptoms of ADHD and may differ depending on the individual’s age.

For example, cognitive behavioral therapy (CBT) and occupational therapy (OT) can effectively treat adults with ADHD. These interventions can help adults learn to adapt behaviors to improve their daily, social, and professional functioning ^[6][7].

For children with ADHD, treatments often involve input from parents and educators to help manage their behaviors in a supportive manner. This may also include approaches used in CBT, such as techniques to improve social skills, organization, and self-management ^[6][8].

Treatment for ADHD will depend on the individual’s symptoms, areas of impaired functioning, and age. Medicinal and therapeutic interventions are commonly combined to provide the most effective treatment option ^[4].

Other potentially helpful interventions include meditation and mindfulness, dietary changes, and exercise. Although there is limited research on these interventions, some have found them effective ^[4][6].

ADD vs. ADHD: What's the difference?

ADHD can be diagnosed as a predominantly inattentive presentation, predominantly hyperactive-impulsive presentation, or a combined presentation. Inattentive ADHD was previously referred to as ADD, while ADHD referred to a hyperactive-impulsive presentation ^[1][2].

As such, the difference between ADD and ADHD is the presenting symptoms. ADD, or now known as inattentive ADHD, involves more internalized symptoms, such as ^[4]:

• Difficulty reading or focusing for long periods
• Wandering thoughts and daydreaming

In contrast, ADHD, or hyperactive-impulsive ADHD, involves more externalized symptoms, such as ^[2]:

• Fidgeting and struggling to sit still for prolonged periods
• Impatience and difficulty waiting
• Talking and moving very quickly and excessively

Therefore, symptoms of the hyperactive-impulsive presentation are often more noticeable, as they are externalized and may be more likely to cause disruption to the surrounding people or environment. Symptoms of inattentive ADHD may be more hidden or unrecognized as they are less outwardly expressed ^[3][5].

Other differences include ^[1][3][8]:

• Inattentive ADHD is diagnosed in around half as many people as hyperactive-impulsive ADHD.
• Inattentive ADHD is often diagnosed in later life, while hyperactive-impulsive ADHD is often diagnosed in childhood.
• Generally, girls are more likely to have inattentive ADHD, while boys are more likely to have hyperactive-impulsive ADHD.
• People with inattentive ADHD may be more likely to experience comorbid conditions such as learning disabilities, depression, and anxiety disorders than hyperactive-impulsive or combined ADHD.