UK and Irish surveillance study of gender identity disorder (GID) in children and adolescents

Purpose: The incidence of childhood/adolescent Gender Identity Disorder (GID) is unknown. GID is an important condition where gender identity differs from biological sex. It is associated with significant distress, particularly with puberty, with much controversy internationally over the optimal timing of hormonal treatment. We examine the incidence and clinical presentation in UK and Irish children and adolescents. Methods: STUDY POPULATION: Children and adolescents aged 4-15.9 years in the UK and Republic of Ireland. DESIGN: Joint British Paediatric Surveillance Unit (BPSU) and Child and Adolescent Psychiatry Surveillance System (CAPSS) study. New cases of GID reported by clinicians over a 19-month reporting period (01-Nov-2011 to 01-June-2013) are validated against the authoritative DSM-IV-TR (2000). Exclusions include disorders of sexual differentiation and major psychosis. PRIMARY OUTCOME: Incidence of childhood/ adolescent GID, calculated by dividing the number of validated cases by the base population of children and adolescents aged 4-15.9 years. Sources of denominator data: UK Office of National Statistics and the Central Statistics Office in Ireland. STATISTICAL ANALYSIS: Descriptive statistics and comparisons using two-sample t-tests or Mann- Whitney U tests for continuous data and Chi-squared or Fisher’sexact tests for categorical data. Results: Preliminary descriptive data from the first 15 months’sur-veillance (n¼ 138 cases, 69 males) indicate that similar numbers of males and females are affected by this condition. Early estimates suggest UK and Irish incidences of 1:80,000 and < 1:200,000 respectively. There is a lag of several years between median [inter- quartile range] onset of symptoms (7y [4-12y]) and presentation to Paediatricians or Psychiatrists (14.5y [11.9-15.2y]), with most cases presenting at 14 or 15 years. Only a quarter of all cases (n¼35) were less than 12 years old at reporting, but 50% of cases reported by Paediatricians. There are high levels of psychiatric co-morbidity at pre- sentation, with at least one other mental health diagnosis in 45%, and two or more other diagnoses in adolescents aged 12 years and over. Conclusions: We present the first ever population-level data on the incidence, clinical features and presentation of childhood/ adolescent GID. These data will inform clinical management, including the highly controversial debate around early pubertal suppression in this group