Attention deficit hyperactivity disorder predominantly inattentive

Attention deficit hyperactivity disorder predominantly inattentive
Classification and external resources

Attention deficit hyperactivity disorder predominantly inattentive (ADHD-PI), formerly attention deficit disorder without hyperactivity,^[1] is one of the three subtypes of attention deficit hyperactivity disorder (ADHD).^[2] The term was formally changed in 1994 in the new Diagnostic and Statistical Manual of Mental Disorders, fourth edition (DSM-IV),^[3][4] to "ADHD predominantly inattentive" (ADHD-PI or ADHD-I). 'Predominantly inattentive' is similar to the other subtypes of ADHD except that it is characterized primarily by inattentive concentration or a deficit of sustained attention, such as procrastination, hesitation, and forgetfulness; it differs in having fewer or no typical symptoms of hyperactivity or impulsiveness. Lethargy/fatigue is sometimes reported, but ADHD-PI is a separate condition from the proposed cluster of symptoms known as sluggish cognitive tempo (SCT).

Classification

ADHD-PI is an attention-concentration deficit that has everything in common with other forms of ADHD except that it has fewer hyperactivity or impulsivity symptoms and has more directed attention fatigue symptoms.^[5]

Different countries have used different ways of diagnosing ADHD-PI. In the United Kingdom, diagnosis is based on quite a narrow set of symptoms, and about 0.5–1% of children are thought to have attention or hyperactivity problems.

Signs and symptoms

DSM-5 criteria

The DSM-5 allows for diagnosis of the predominantly inattentive subtype of ADHD (code 314.00) if the individual presents six or more (five for adults) of the following symptoms of inattention for at least six months to a point that is disruptive and inappropriate for developmental level:

• Often does not give close attention to details or makes careless mistakes in schoolwork, work, or other activities.
• Often has trouble keeping attention on tasks or play activities.
• Often does not seem to listen when spoken to directly.
• Often does not follow instructions and fails to finish schoolwork, chores, or duties in the workplace (not due to oppositional behavior or failure to understand instructions).
• Often has trouble organizing activities.
• Often avoids, dislikes, or doesn't want to do things that take a lot of mental effort for a long period (such as schoolwork or homework).
• Often loses things needed for tasks and activities (e.g. toys, school assignments, pencils, books, or tools).
• Is often easily distracted.
• Is often forgetful in daily activities.^[6]

An ADHD diagnosis is contingent upon the symptoms of impairment presenting themselves in two or more settings (e.g., at school or work and at home). There must also be clear evidence of clinically significant impairment in social, academic, or occupational functioning. Lastly, the symptoms must not occur exclusively during the course of a pervasive developmental disorder, schizophrenia, or other psychotic disorder, and are not better accounted for by another mental disorder (e.g., mood disorder, anxiety disorder, dissociative disorder, personality disorder).

Life Period	Examples of Observed Symptoms
Children	Failing to pay close attention to details or making careless mistakes when doing school-work or other activities
	Trouble keeping attention focused during play or tasks
	Appearing not to listen when spoken to (often being accused of "daydreaming")
	Failing to follow instructions or finish tasks
	Avoiding tasks that require a high amount of longer-term mental effort and organization, such as school projects
	Frequently losing items required to facilitate tasks or activities, such as school supplies
	Excessive distractibility
	Forgetfulness
	Procrastination, inability to begin an activity, such as completing homework
Adults	Procrastination; delaying or avoiding starting projects that require vigilant mental effort
	Difficulty sustaining concentration on conversations or briefly losing attention on someone speaking
	Hesitation to sustain concentration in planning and organizing for the completion of tasks
	Hesitative responses, doubt, and delayed execution due to inattention remembering information
	Difficulty finishing projects or completing assignments because many tasks simultaneously on the go
	Forgetting to complete tasks and details after temporarily switching to more stimulating tasks
	Difficulty finding misplaced tools after task switching due to bypassing adequate memory storage
	Sustained information processing is slower than others causing information gaps that inhibit execution
	Problems remembering appointments, obligations, or instructions
	Difficulty learning new projects when concentration deficits cause desire to multitask or daydream
	Distracted from persevering during work; difficulty holding onto a job for a significant amount of time
	Change plans to the inconvenience of others due to forgetting or not fully aware of the bigger scenario
	Maintaining excessive personal items such as storing old items of diminished usefulness
	Obsessive behavior as compensation or coping mechanism for a perseverance deficit
	Difficulty transitioning to new task or activity due to obsessive behavior
	Higher rate of vigilant concentration fatigue after inhibiting many distractions from greater effort required

Treatment

Although ADHD has most often been treated with medication, medications do not cure ADHD. They are used solely to treat the symptoms associated with this disorder and the symptoms will come back once the medication stops.^[7]

Pharmacological

Stimulants are typically formulated in fast and slow-acting as well as short and long-acting formulations. The fast-acting amphetamine mixed salts (Adderall) and its derivatives, with short and long-acting formulations bind to the trace amine associated receptor and triggers the release of dopamine into the synaptic cleft.^[8] They may have a better cardiovascular disease profile than methylphenidate and potentially better tolerated.^[9]

The fast-acting methylphenidate (Ritalin), is a dopamine reuptake inhibitor.^[10] In the short term, methylphenidate is well tolerated. However, long term studies have not been conducted in adults and concerns about increases in blood pressure have not been established.^[11]

The slow and long-acting nonstimulant atomoxetine (Strattera), is primarily a norepinephrine reuptake inhibitor and, to a lesser extent, a dopamine reuptake inhibitor. It may be more effective for those with predominantly inattentive concentration.^[12] It is sometimes prescribed in adults who do not get enough vigilant concentration response from mixed amphetamine salts (Adderall) or get too many side effects.^[13] It is also approved for ADHD by the US Food and Drug Administration.

The use of cholinergic adjunctive medications is uncommon and their clinical effects are poorly researched;^{[14][15][16][17]} consequently, cholinergics such as galantamine or varenicline would be off label use for ADHD.^[18][19][20] New nicotinic cholinergic medications in development for ADHD are pozanicline,^[21][22] ABT-418,^[23] and ABT-894.^[24]

Prognosis

In some cases, children who enjoy learning may develop a sense of fear when faced with structured or planned work, especially long or group-based that requires extended focus, even if they thoroughly understand the topic. Children with ADHD may be at greater risk of academic failures and early withdrawal from school.^[25] Teachers and parents may make incorrect assumptions about the behaviours and attitudes of a child with ADHD-PI, and may provide them with frequent and erroneous negative feedback (e.g. "careless", "you're irresponsible", "you're immature", "you're lazy", "you don't care/show any effort", "you just aren't trying", etc.).^[26]

The inattentive children may realize on some level that they are somehow different internally from their peers. However, they are also likely to accept and internalize the continuous negative feedback, creating a negative self-image that becomes self-reinforcing. If these children progress into adulthood undiagnosed or untreated, their inattentiveness, ongoing frustrations, and poor self-image frequently create numerous and severe problems maintaining healthy relationships, succeeding in postsecondary schooling, or succeeding in the workplace. These problems can compound frustrations and low self-esteem, and will often lead to the development of secondary pathologies including anxiety disorders, sexual promiscuity, mood disorders, and substance abuse.^[25]

It has been suggested^[5] that some of the symptoms of ADHD present in childhood appear to be less overt in adulthood. This is likely due to an adult's ability to make cognitive adjustments and develop compensating or coping skills to minimize the impact of inattentive or hyperactive symptoms. However, the core problems of ADHD do not disappear with age.^[25] Some researchers have suggested that individuals with reduced or less overt hyperactivity symptoms should receive the ADHD-combined diagnosis. Hallowell and Ratey (2005) suggest^[27] that the manifestation of hyperactivity simply changes with adolescence and adulthood, becoming a more generalized restlessness or tendency to fidget.

A meta-analysis of 37 studies on cognitive differences between those with ADHD-Predominantly Inattentive type and ADHD-Combined type found that "the ADHD-C subtype performed better than the ADHD-PI subtype in the areas of processing speed, attention, performance IQ, memory, and fluency. The ADHD-PI subtype performed better than the ADHD-C group on measures of flexibility, working memory, visual/spatial ability, non-verbal IQ, motor ability, and language. Both the ADHD-C and ADHD-PI groups were found to perform more poorly than the control group on measures of inhibition, however, there was no difference found between the two groups. Furthermore the ADHD-C and ADHD-PI subtypes did not differ on measures of sustained attention."^[28]

Epidemiology

It is difficult to say exactly how many children worldwide have ADHD because different countries have used different ways of diagnosing it, while some do not diagnose it at all. In the UK, diagnosis is based on quite a narrow set of symptoms, and about 0.5–1% of children are thought to have attention or hyperactivity problems. In comparison, professionals in the U.S. used a much broader definition of the term ADHD until recently. This meant up to 10% of children in the U.S. were described as having ADHD. Current estimates suggest that ADHD is present internationally in about 7.2% of children.^[29] About five times more boys than girls are diagnosed with ADHD. Boys are seen as the prototypical ADHD child, therefore they are more often diagnosed with ADHD than girls.^[30] This may be partly because of the particular ways they express their difficulties. Boys and girls both have attention problems, but boys are more likely to be overactive and difficult to manage. Children from all cultures and social groups are diagnosed with ADHD. However, children from certain backgrounds may be particularly likely to be diagnosed with ADHD, because of different expectations about how they should behave. It is therefore important to ensure that a child's cultural background is understood and taken into account as part of the assessment.

History

In the DSM-III, sluggishness, drowsiness, and daydreaming were listed as characteristics of ADD without hyperactivity. These symptoms were removed from the ADHD criteria in DSM-IV even though many of those with ADHD were found to have these symptoms along with hyperactive symptoms. These distinct symptoms in the absence of hyperactivity though were described in a separate category called sluggish cognitive tempo.

References

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