Sleep impairment in Attention Deficit Hyperactivity Disorder (ADHD) Is it an additional symptom of ADHD or the result of comorbidities?

Abstract

Attention Deficit Hyperactivity Disorder (ADHD) is a quite common neuropsychiatric ailment affecting all ages. The diagnosis is based on clinical judgement without a biological diagnostic marker. Thus, both over – and – underdiagnoses are not a rarity. Since it is a developmental disorder the clinical features are altered with age but the classical “triad” of inattention, hyperactivity and impulsivity remain in the majority of the patients throughout their life span. A number of comorbidities are associated with the disorder and in many patients their presence imposes a negative effect on life quality which may be more prominent than that caused directly by the classical "triad". Although cases with the triad have been reported during the last 200 years, the concept of ADHD was solidified in 1987. Sleep impairment as an important comorbidity of ADHD has been slowly unrevealed. Surprisingly, even in DSM-5, any form of sleep impairment was not mentioned in ADHD. This paper is a review of the prevalence, characteristics and possible aetiology of sleep impairment in youngsters and adults with ADHD. Also, the bidirectional association between impaired sleep quality and ADHD is discussed in an attempt to clarify whether impaired sleep is an additional symptom of “pure” ADHD, is the sole result of associated comorbidities or is the result of both.