Elevated hypothalamic/midbrain serotonin (monoamine) transporter availability in depressive drug-naive children and adolescents

Cumulative data suggest depression in adulthood being connected to reduced availability of brain serotonin while the role of dopamine remains less specific. Prospective studies have shown a continuity of depressive episodes from childhood to adulthood, combined with poor social function and excess mortality. The object of this study was to examine whether alterations in brain serotonin and/or dopamine transporter levels are already present in depressive children and adolescents. We examined 41 drug-naive patients (aged 7-17) by single photon emission tomography (SPET) using iodine-123-labelled 2 beta-carbomethoxy-3 beta(iodophenyl) tropane [I-123]P-CIT as a tracer for monoamine transporters. In addition to the ordinary clinical examination, the patients were given a structured interview and Information was gathered from teachers and parents with questionnaires. The diagnoses were established by consensus evaluation between three child psychiatrists. To test the serotonin hypothesis and the dopamine hypothesis regarding depression in children and adolescents, the series was divided into groups with depression present (31) and no depression present (10). In this study, the depressive child and adolescent patients had significantly higher serotonin transporter availability (P < 0.02) in the hypothalamic/midbrain area. Age did not correlate to the hypothalamic/midbrain serotonin transporter binding ratio. No significant difference in dopamine transporter availability in striatum was found between the depressive and the nondepressive children and adolescents.