The nature and nurture of ADHD and its comorbidities: a narrative review on twin studies

Publication date: Available online 12 December 2019Source: Neuroscience & Biobehavioral ReviewsAuthor(s): Naomi Tistarelli, Corrado Fagnani, Miriam Troianiello, Maria Antonietta Stazi, Walter AdrianiAbstractAttention-deficit/hyperactivity disorder (ADHD) is a common neurodevelopmental disorder in children worldwide, and also the recognition of its persistence into adulthood is increasing. While ADHD in childhood is highly heritable and mostly driven by familial factors, during adulthood it appears to show a lower heritability, even if there is not total agreement on this yet. This disorder often co-occurs with many other conditions, which also vary across the different stages of development, and several studies have used the twin design to investigate these comorbidities, giving valuable insights into the origins of the observed co-occurrence. This review aims to summarize the main results of twin research, according to the following domains: individual traits, cognitive impairment, behavioral manifestations, clinical conditions and psychosocial risk factors. Individual features seem to play a role in this symptomatology and include personality traits such as negative emotionality, personality disorders and temperamental dimensions with a predominance of novelty seeking. At a lower level, ADHD is associated with both functional and anatomic brain characteristics. ADHD is also associated with some forms of cognitive impairment, such as sluggish cognitive tempo, and learning di...
Source: Neuroscience and Biobehavioral Reviews - Category: Neuroscience Source Type: research