Psychometric and clinical prevalence and comorbidity study of attention deficit hyperactivity disorder in Castilla y Leon (Spain)

Objective: to determine the prevalence rate of attention deficit hyperactivity disorder (ADHD) in school age children (6-16 years) in Castilla y León.

Subjects and methods: a multi-staged stratified proportional cluster (rural and urban) people sample population study was selected. Target population: 212,657. Sample: 1,095. A psychometric first step (ADHD rating Scales IV for parents and teachers) was used to collect data, and a second one, using DSM-IV criteria, for clinical confirmation. Child Symptom Inventory was used to study comorbidity, and DSM-IV for clinical confirmation.

Results: a prevalence of 6.66 % global rate was obtained (IC 95 %: 5.1-8.1%). We also obtained hyperactive subtype 1%; disattentional subtype 1.27 % and combined subtype 4.38%.

Prevalence rate in males (8.97%) is significantly higher than in females (4.18%), while for academic levels, schools or areas, differences are not significant. Prevalence rates in Primary School (6.8%) is similar to Secondary School (6.48%). Seventy one percent of the cases of ADHD have some type of comorbidity: anxiety disorders 46%, behavioural disorders 31%, mood disorders 9%, tics disorders 10%, and enuresis 12%. ADHD cases have significantly worse academic results and worse classroom behaviour.

Conclusions: prevalence rates of ADHD in Castilla y León are very close to the world average. The cases have high comorbidity and present impairment in academic performance and scholar behaviour.