Restless legs syndrome as a possible predictor for psychiatric disorders in parents of children with ADHD.

Attention-deficit hyperactivity disorder (ADHD) is a common disorder with estimated prevalence of 5% in children and 3.4% in adults. Psychiatric disorders are a frequent concomitant feature. Restless legs syndrome (RLS) may mimic the symptoms of ADHD. The aim of the study is to evaluate whether the presence of RLS predicts occurrence of psychiatric disorders in parents of children with ADHD. Thirty-seven parents of 26 children with ADHD were examined for RLS and for lifetime prevalence rates of psychiatric disorders and personality disorders based on the Structured Clinical Interview for DSM-IV Diagnoses (SCID). Prevalence rates in parents were 29.7% for RLS, 67.6% for Axis I and 40.5% for Axis II disorders. Mothers revealed higher rates for depression, anxiety disorders and ADHD than fathers, whereas personality disorders occurred at higher rates in fathers. The presence of RLS predicted a diagnosis of ADHD (odds ratio (OR) 21.9), agoraphobia (OR = 20.4) and any anxiety disorder (OR = 8.5). Although limited by the small sample size, we found evidence for increased rates of cluster B personality disorders (OR = 59.3) in parents with RLS. All parents of the latter group (100%) reported a positive family history of psychiatric disorders which was not the case in parents without RLS (69.2%) excluding the index children with ADHD. RLS seems to indicate increased vulnerability for psychiatric disorders, i.e., ADHD and anxiety disorders, in a subgroup of parents from ADHD children. Synaptic dysfunction affecting dopaminergic transmission among other transmitter systems may be a common final pathway related to the phenotypic spectrum of ADHD.

Intranasal atrial natriuretic peptide acts as central nervous inhibitor of the hypothalamo-pituitary-adrenal stress system in humans.

Increased hypothalamo-pituitary-adrenal activity contributes to morbidity in widespread metabolic and psychiatric diseases. Inhibition of hypercortisolism represents a promising therapeutic strategy in these conditions, which currently cannot be used. Here, we tested the hypothesis that atrial natriuretic peptide (ANP) administered intranasally is a safe and feasible inhibitor of pituitary-adrenal activity at the central nervous level. Thirty minutes after intranasal administration of ANP (1 mg) and placebo, pituitary-adrenal activity was stimulated in 18 healthy men by two tests: 1) a standard insulin-hypoglycemia test and 2) CRH combined with vasopressin (VP), respectively. ACTH, cortisol, VP, blood pressure, heart rate, and measures of fluid balance were also recorded. Pretreatment with ANP suppressed cortisol (P < 0.01) and ACTH (P < 0.05) secretory responses to insulin-induced hypoglycemia to about half of that seen after placebo, but pituitary-adrenal activity was not suppressed by CRH/VP injection (P > 0.7). Indicators of fluid balance, cardiovascular parameters, and self-report measures were not influenced by the treatment. Results indicate a strong inhibition of stimulated pituitary-adrenal activity after intranasal administration of ANP. The absence of an effect on CRH/VP-induced pituitary-adrenal responses suggests a direct action of the peptide on the central nervous system inhibiting stimulated hypothalamo-pituitary-adrenal activity at the hypothalamic level.