HYPERACTIVITY AND GRAVES' DISEASE

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Rosenthal R (1966), ExperimenterEfficts in BehavioralResearch. New York: Appleton-Century-Crofts Weiss B, Weisz JR (1995), Relative effectiveness of behavioral versus nonbehavioral child psychotherapy. J Consult Clin PsychoI63:317-320

HYPERACTIVITY AND GRAYES' DISEASE To the Editor: The high prevalence ofADHD in individuals with generalized resistance to thyroid hormone (GRTH) has provoked interest in the appropriateness of thyroid testing in children with ADHD. GRTH is an uncommon disorder and, as noted in the article by Elia et al. (1994), screening of all children with ADHD for thyroid abnormalities has been unrewarding. However, hyperthyroidism, usually from Graves' disease, is a known, treatable cause of hyperactivity (Barnes et aI., 1977) and should continue to be considered in the differential diagnosis of ADHD. The prevalence of Graves' disease in the U.S. is 0.02% to 0.4% (Furszyfer et al., 1972), and childhood cases account for up to 5% of total cases (Vaidya et aI., 1974). The incidence peaks during adolescence, with two thirds of cases occurring between ages 10 and 15 years (Vaidya et aI., 1974). A retrospective chart review of pediatric endocrine patients seen in our practice over the past 7 years identified 21 children and adolescents with Graves' disease. There was only one child with the diagnosis of GRTH, but she did not have ADHD. The total population in our referral area is about 700,000. The age at diagnosis was 60/12 to 17712 years, but 86% were older than 9 years. All had resting heart rates greater than 95 beats per minute and 73% had a goiter or thyroid enlargement. Hyperactivity was present in 87% of thyrotoxic children. Two children were taking methylphenidate. Poor grades with a recent (in the previous 2 to 12 months) dramatic drop in school performance was seen in 95%, and 73% slept poorly. There were mood swings in 53%, 47% had difficulty concentrating, and 40% were irritable or easily angered. All children had relief of these symptoms with treatment of Graves' disease except one, who is presumed to have both ADHD and Graves' disease. His hyperactivity decreased but did not rcrn ir. Graves' disease begins and progresses insidiously. While tachycardia and goiter are two of the most reliable signs of Graves' disease (Vaidya et aI., 1974), this disorder is not always easy to diagnose. Prompt diagnosis is essential because treatment provides relief from hyperactivity and the other very disruptive symptoms. Clinical experience and the pediatric endocrine literature suggests that children with the onset of hyperactivity after

]. AM. ACAD. CHILD ADOLESC. PSYCHIATRY, 34:8, AUGUST 1995

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age 9, persistent, resting tachycardia, and/or goiter should have thyroid function tests to detect hyperthyroidism. Thyroid testing of children with a decreased growth velocity and goiter, as mentioned in the letter by Bhatara et al. (1994), will detect hypothyroidism. While this is a worthwhile endeavor, hypothyroidism has not been regarded as a cause of hyperactivity and treatment may even initially worsen hyperactivity (Rovet et aI., 1993). We agree that guidelines for thyroid function studies in ADHD should be developed. Andrea J. Eberle, M.D., Ph.D. University of Tennessee Medical Center, Knoxville

Barnes HV, Blizzard RM (1977), Antithyroid drug therapy for toxic diffuse goiter (Graves disease): thirty years experience in children and adolescents. J Pediatr 91:313-320 Bhatara VS, Kummer M, McMillin JM, Bandenini F (1994), ADHD and the thyroid. JAm Acad Child Adolesc Psychiatry 33:1057 Elia J, Gulotta C, Rose SR, Marin G, Ropoporr JL (1994), Thyroid function and attention-deficit hyperactivity disorder. JAm Acad Child

Adolesc Psychiatry 33: 169-172 Furszyfer J, Kurland LT, McConahey WM (1972), Epidemiological aspects of Hashimoto's thyroiditis and Graves' disease in Rochester Minn

1935-1967. Metabolism 21:197 Rovet JF, Danernan D, Bailey JD (1993), Psychologic and psychocducational consequences of thyroxine therapy for juvenile acquired hypothyroidism. J Pediatr 122:543-549 Vaidya VA, Bongiovanni AM, Parks JS, Tenore A, Kirkland RT (1974), Twenty-two years experience in the medical management of juvenile thyrotoxicosis. Pediatrics 54:565-570

Dr. Elia replies: Dr. Eberle's data and clinical observations support our hypothesis that ADHD symptoms are not characteristic of GRTH but are also present in the more commonly occurring hyperthyroid disorders such as Graves. GRTH is rare, and therefore screening all ADHD children for this disorder is impractical. Is it, however, necessalY to screen ADHD children for the more commonly occurring and treatable hyperthyroid disorders such as Graves? ADHD and Graves' disease have different time lines. As Dr. Eberle notes, the incidence of Graves' disease peaks during adolescence, with two thirds of cases occurring between ages 10 and 15 years. This is also supported by her sample (86% were older than age )l). To arrive at a diagnosis ofADHD, some hyperactive, impulsive, or inattentive symptom that caused impairment would have to have been present before age 7 (DSM-IV) (American Psychiatric Association, 1994). This suggests that a thorough history rather than any laboratory tests would be more helpful in differentiating the two. New-onset hyperactivity, impulsivity, or distractibility after age 7 is inconsistent with ADHD and should not only

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