Objective. To examine associations among attention-deficit/hyperactivity disorder (ADHD) symptom dimensions (hyperactivity, impulsivity, inattention, and sluggish cognitive tempo [SCT]) and functional impairment among adults. The potential influence of co-occurring internalizing and externalizing difficulties, as well as self-reported executive functioning deficits, on these associations was also evaluated.
Methods. One thousand eight hundred and ninety-four adults (58.8% female; 75.9% Caucasian; age: M = 36.24 [SD = 11.65] years) recruited from Amazon’s Mechanical Turk (MTurk) completed extensive questionnaire batteries assessing ADHD symptoms, co-occurring internalizing and externalizing difficulties, executive functioning deficits, and functional impairment across a range of domains. First, factor analyses were completed to identify empirically-derived functional impairment factors for use in subsequent analyses. Second, associations between ADHD symptom dimensions and functional impairment factors were examined via a path model. Third, multiple mediation analyses were conducted to evaluate the impact of ADHD symptom dimensions on functional impairment domains via internalizing and externalizing difficulties. Finally, additional multiple mediation analyses were completed to examine to influence of ADHD symptom dimensions on functional impairment via self-reported executive functioning deficits.
Results. Factor analyses identified four overlapping but distinct functional impairment factors indexing general impairment, quality of life, romantic relationship functioning, and social support. Path analyses revealed significant associations between increased ADHD symptoms and higher general impairment, lower quality of life, reduced romantic relationship functioning, and decrements in perceived social support. Multiple mediation analyses indicated that ADHD symptom dimensions influence functional impairment domains via specific internalizing, externalizing, and executive functioning difficulties.
Conclusions. The pattern of findings provides further support for associations between ADHD symptom dimensions and a range of functional impairments, as well as highlighting potential exacerbation of these effects in the presence of co-occurring mental health and executive functioning difficulties. Current findings may help to clarify the complex phenomenology of ADHD in adults, and carry implications for improving extant treatment approaches.