Attention-Deficit/Hyperactivity Disorder Predominantly Inattentive Subtype/Presentation: Research Progress and Translational Studies

Abstract

Research on the predominantly inattentive attention-deficit/hyperactivity disorder (ADHD-PI) subtype/presentation is important given its high prevalence, but paradoxically it is under-recognized and undertreated. The temporal stability of the inattention symptom could impact the high worldwide prevalence of ADHD-PI. Some evidence suggests differences in the nature of attentional deficit in ADHD-PI vs. that in other subtypes. Impairments in neuropsychological, neurocognitive, and social functioning are also evident in ADHD-PI, which could be specific to the subtype (e.g., processing speed, social perception, and skills), or differ from others in severity. Neuroimaging studies have also revealed ADHD-PI-specific neuropathological abnormalities and those that are shared with other subtypes. ADHD-PI is highly comorbid with learning and internalizing (e.g., anxiety and depression) disorders. There is no solid evidence for ADHD-PI-specific genetic etiologies and differential responses of subtypes to ADHD medications. Translational studies have used the Wistar Kyoto/NCrl substrain which requires further characterizations as an ADHD-PI model. Overall, ADHD-PI research has been conducted in the context of the Diagnostic and Statistical Manual, which arguably does not conform to the widely recognized “dimensional” view of ADHD. The Research Domain Criteria has been proposed to provide a novel framework for understanding the nature of neuropsychiatric illnesses and ultimately improve their diagnosis and treatment.

Associations between Family Functioning and Symptoms of Attention-Deficit Hyperactivity Disorder (ADHD): A Cross-Sectional Study

“…These two dimensions of the McMaster Family Functioning Model provide a structured environment, including consistent house rules, expectations, and consequences clearly understood by all family members. This structured environment through good family roles and behavior control may provide benefits in maintaining self-control for children with ADHD who are characterized by difficulty in self-regulation, lack of persistence, and disorganization [ 20 , 21 ].…”

“…When considering the associations between family functioning and controlled ADHD symptoms for each subscale, a positive association between good family roles and controlled ADHD symptoms inattention subscale was observed, but no association was found for the ADHD hyperactivity/impulsivity subscale. Good family roles are likely more specific to the core symptoms of ADHD inattention type, which are characterized by difficulties sustaining attention in tasks, following through on instructions, finishing chores, and organizing tasks [ 20 ]. On the contrary, the literature suggests that hyperactivity/impulsivity symptoms often diminish with age [ 23 ], and thus, family functioning may not play a key role in this specific subscale of symptoms.…”

Caring for adolescents and young adults with attention-deficit/hyperactivity disorder in primary care: seizing opportunities to address youth mental health needs

“…There are three ADHD presentations described in the DSM-5: Predominantly Inattentive, Predominantly Hyperactive and Impulsive, and ADHD Combined, in which both hyperactivity/impulsivity and inattention are present [2,15 ▪▪ ]. The most common presentation of ADHD in AYA is Predominantly Inattentive since hyperactivity and impulsivity may lessen or manifest differently as children mature, but symptoms of inattentiveness tend to remain consistent [15 ▪▪ ].…”

“…The AAP clinical practice guideline for ADHD advises that pediatricians and other PCPs evaluate children and adolescents for ADHD when they present with academic or behavioral problems and symptoms of inattention, hyperactivity or impulsivity [4]. There are three ADHD presentations described in the DSM-5: Predominantly Inattentive, Predominantly Hyperactive and Impulsive, and ADHD Combined, in which both hyperactivity/impulsivity and inattention are present [2,15 ▪▪ ]. The most common presentation of ADHD in AYA is Predominantly Inattentive since hyperactivity and impulsivity may lessen or manifest differently as children mature, but symptoms of inattentiveness tend to remain consistent [15 ▪▪ ].…”

Response inhibition in children with different subtypes/presentations of attention deficit hyperactivity disorder: A near-infrared spectroscopy study

“…Children with different subtypes of ADHD differ not only in clinical presentation, comorbidities, and response to treatment, but also in pathogenesis (Willcutt et al, 2012;de la Peña et al, 2020). Children with ADHD-PI have greater activation in temporal and parietal regions and bilateral middle frontal gyrus than those with ADHD-C. Children with ADHD-C have greater activation in the bilateral medial occipital lobes than those with ADHD-PI (Solanto et al, 2009).…”