23 This study investigated the association between attention-deficit/hyperactivity disorder (ADHD) 24 symptomatology in preschool-aged children who were born very preterm (<32 weeks) and cognitive 25 outcomes, clinical risk and socio-demographic characteristics. 119 very preterm children who participated 26 in the Evaluation of Preterm Imaging Study at term-equivalent age were assessed at a mean age of 4.5 27 years. Parents completed the ADHD Rating Scale IV, a norm-referenced checklist that evaluates ADHD 28 symptomatology according to diagnostic criteria, and the Behavior Rating Inventory of Executive 29 Function-Preschool version. Children completed the Wechsler Preschool and Primary Scales of 30 Intelligence and the Forward Digit Span task. Longitudinal data including perinatal clinical, qualitative 31 MRI classification, socio-demographic variables and neurodevelopmental disabilities were investigated in 32 relation to ADHD symptomatology. All results were corrected for multiple comparisons using false 33 discovery rate. Results showed that although the proportion of very preterm children with clinically 34 significant ADHD did not differ from normative data after excluding those with neurodevelopmental 35 disabilities, 32.7% met criteria for subthreshold ADHD inattentive type and 33.6% for combined type, 36 which was higher than the expected 20% in normative samples. Higher ADHD symptom scores (all) were 37 associated with greater executive dysfunction (inhibitory self-control, flexibility, and emergent 38 metacognition, corrected p<0.001 for all tests). Higher inattentive ADHD symptom scores were 39 associated with lower IQ (ρ=-0.241, p=0.036) and higher perinatal clinical risk (more days on mechanical 40 ventilation (ρ=0.206, p=0.025) and more days on parenteral nutrition (ρ=0.223, p=0.015)). Higher 41 hyperactive ADHD symptom scores instead were associated with lower socio-economic status (ρ=0.278, 42 p=0.002). These results highlight the importance of monitoring and supporting the development of very 43 preterm children throughout the school years, as subthreshold ADHD symptoms represent risk factors for 44 psychosocial problems and for receiving a future clinical diagnosis of ADHD. 45 3 46 List of Abbreviations and Acronyms: 47 ADHD (Attention-deficit/hyperactivity disorder) 48 MRI (magnetic resonance imaging) 49 NDD (Neurodevelopmental disability) 50 51 52 53 54 55 56 57 58 59 60 4 61 Introduction 62 Attention-deficit/hyperactivity disorder (ADHD) is a neurodevelopmental condition which affects 5-7%63 of children, depending on the source of information used to reach a diagnosis (1, 2). Children who were 64 born very preterm (< 32 weeks of gestation) have a 2-to 3-fold increased risk of being diagnosed with 65 ADHD compared to their term born peers (4-fold risk in those born at < 26 weeks) (3-7).
66According to the fifth edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-67 V), ADHD is characterized by two main symptom presentations, inattention and hyperactivity-68 impulsivit...