Polymorphisms of the dopamine D4 receptor, clinical outcome, and cortical structure in attention-deficit/hyperactivity disorder.

CONTEXT: Attention-deficit/hyperactivity disorder (ADHD) is one of the most heritable neuropsychiatric disorders, and a polymorphism within the dopamine D4 receptor (DRD4) gene has been frequently implicated in its pathogenesis. OBJECTIVE: To examine the effects of the 7-repeat microsatellite in the DRD4 gene on clinical outcome and cortical development in ADHD. We drew comparisons with a single nucleotide polymorphism in the dopamine D1 receptor (DRD1) gene, which was associated with ADHD within our cohort, and a polymorphism within the dopamine transporter (DAT1) gene, reported to have additive effects with the DRD4 7-repeat allele. DESIGN: Longitudinal cohort study. SETTING: National Institutes of Health, Bethesda, Maryland. PARTICIPANTS: One hundred five children (with 222 neuroanatomical magnetic resonance images) with ADHD (mean age at entry, 10.1 years) and 103 healthy controls (total of 220 magnetic resonance images). Sixty-seven subjects with ADHD (64%) had follow-up clinical evaluations (mean follow-up, 6 years). MAIN OUTCOME MEASURES: Cortical thickness across the cerebrum and presence of DSM-IV-defined ADHD at follow-up. RESULTS: Possession of the DRD4 7-repeat allele was associated with a thinner right orbitofrontal/inferior prefrontal and posterior parietal cortex. This overlapped with regions that were generally thinner in subjects with ADHD compared with controls. Participants with ADHD carrying the DRD4 7-repeat allele had a better clinical outcome and a distinct trajectory of cortical development. This group showed normalization of the right parietal cortical region, a pattern that we have previously linked with better clinical outcome. By contrast, there were no significant effects of the DRD1 or DAT1 polymorphisms on clinical outcome or cortical development. CONCLUSIONS: The DRD4 7-repeat allele, which is widely associated with a diagnosis of ADHD, and in our cohort with better clinical outcome, is associated with cortical thinning in regions important in attentional control. This regional thinning is most apparent in childhood and largely resolves during adolescence.

Sleep disturbances in childhood-onset schizophrenia.

Sleep disturbances in psychiatric disease have long been reported. However, research on sleep disturbances in child and adolescent psychiatric disorders is limited. We examined the relationship of sleep disturbance to clinical severity and co-morbid diagnoses (e.g. anxiety), for a population with childhood-onset schizophrenia (COS). Sixty-one COS patients underwent a medication-free inpatient observation period as part of an NIMH study of COS. Sleep quantity during the last 5-7 days of a patient's medication-free period was measured using safety records and daily nursing notes. Subjects were divided into two groups: "good sleepers" (>6 h) and "poor sleepers" (<6 h) based on the average of total hours slept per night. Comparisons between groups were made with respect to clinical ratings at both admission and during washout period, co-morbid diagnosis of generalized anxiety disorder (GAD) and a susceptibility gene (G72) for COS. The median average sleep score for the entire group was 6.1 (S.D.=2.01) h. The good and poor sleep groups differed significantly in terms of severity of positive symptoms (SAPS) and negative symptoms at admission (SANS) both on admission and during the medication-free period. There was no significant relationship between G72 genotypes and a past and/or present diagnosis of GAD. COS patients suffer from significant sleep disturbances and the sleep disturbance is highly related to the symptom severity. As there are numerous health implications of poor sleep, clinicians should have a low threshold for treating sleep disturbances in this population.