complex congenital heart disease are at increased risk of neurodevelopmental impairment, particularly those with a functionally univentricular heart.220 Although studies report a lower mean intelligence quotient for groups of children and young people with a Fontan circulation compared with healthy peers,221,222 the majority of patients have intellectual function within the normal range.223 However, there is a higher prevalence of impairments in executive functioning, visual construction and perception, fine and gross motor skills, language, attention, and academic performance in childhood compared with population norms.220,224–227 Risk and severity of neurodevelopmental impairment are associated with individual factors (e.g., presence of a genetic syndrome, hypoplastic left heart syndrome, structural brain abnormalities, cyanosis, genetic factors) and environmental factors (e.g., prolonged deep hypothermic circulatory arrest during cardiac surgery, postoperative seizures, longer length of hospital stay, lower socioeconomic status, greater psychological stress).225,226,228,229 Although many pediatric cardiac centers currently include neurodevelopmental clinics, the same attention has not been paid to neurocognitive health in adult CHD care Without effective intervention and support, hardships encountered during childhood can endure for years after cardiac diagnosis and treatment It is also possible for difficulties to emerge for the first time in adolescence or adulthood, with heart failure, atrial fibrillation, cardiac surgery, and recurrent strokes increasing vulnerability to neurocognitive impairment later in life Psychological Health Illness-related stressors can challenge children and young people's emerging coping skills during the peak years of onset for mental health disorders Children and adolescents with a Fontan circulation (aged 10 to 19 years) have been found to have higher rates of lifetime psychiatric diagnosis (65%) compared with healthy referents (22%), particularly anxiety disorders (Fontan: 35%, referent: 7%) and disruptive behavior disorders such as attention-deficit/hyperactivity disorder (Fontan: 34%, referent: 6%).230 Health-related fears, separation anxiety, body image concerns, and sleeping difficulties are also common Overall, patient-specific demographic, perinatal, medical, and psychosocial factors tend to be better predictors of later psychological outcomes than intraoperative factors.230–232 Several mechanisms for psychological morbidity in complex CHD are important to consider Exposure to early physiological risk, such as in utero brain immaturity,233 perioperative hemodynamic alterations, and systemic inflammation,234 may adversely affect neurobiologic development and consequently alter long-term responses to stress, increasing the risk of psychological morbidity In addition, studies of individuals exposed to high levels of stress early in life consistently show that the experience of early adversity is associated with disrupted child-parent attachment and alterations in the developmental trajectories of networks in the brain associated with emotion and cognition.235 Parents231,236 and siblings237 also experience higher levels of psychological distress compared with population norms, yet these groups may be vulnerable to falling between the cracks in terms of clinical assessment and access to evidence-based emotional health care.231 Parents with high distress report poorer physical health,238 greater parenting burden,239 higher health service use,240 and more suicidal ideation241 compared with parents of children with complex CHD with lower distress Many who suffer from these difficulties never receive psychological treatment.242 Clinical Implications Without effective intervention, psychological effects can be enduring and can influence a patient's capacity to successfully transition from pediatric to adult health services, with potentially life-threatening consequences.243,244 Evidencebased, theoretically grounded interventions may mitigate the development of mental health difficulties in response to serious illness across the family system Regular screening and assessment for psychological morbidity in people of all ages with a Fontan circulation and their families are clearly indicated.230,231 In general, integrating psychosocial assessment within a clinical setting with which patients are already engaged is a key factor distinguishing successful and unsuccessful early mental health interventions, improving treatment uptake and mental health outcomes.245 However, at this time of writing there are no published data on the efficacy of psychological interventions developed specifically for children or adults with a Fontan circulation Future Directions Although it is clear we need to address psychological vulnerabilities across the family system, the best framework through which to do so remains to be determined Early theories conceptualized the illness experience as a trauma for the patient, leading to an emphasis on trauma-focused psychological therapies Despite the inclusion of life-threatening illnesses as meeting criteria for a traumatic event within the Diagnostic and Statistical Manual of Mental Disorders, researchers have more recently critiqued this diagnostic conceptualization due to the lack of clarity regarding one triggering traumatic event Going forward, we need to better understand the mechanisms underlying psychological morbidity for children and adults with a Fontan circulation and their families and to continue efforts to foster integrated models of psychological and neurocognitive care These represent some of the next frontiers of research and clinical practice in the field ... Without effective intervention, psychological effects can be enduring and can influence a patient's capacity to successfully transition from pediatric to adult health services, with potentially life-threatening consequences.243,244 Evidencebased, theoretically grounded interventions may mitigate the development of