Background: There is emerging evidence that early onset obsessive-compulsive disorder (OCD) may be a phenomenologically distinct subtype of the disorder. Previous research has shown that individuals who report an early onset display greater severity and persistence of symptoms, and they may be less responsive to treatment. To date, this question has been investigated solely in adult samples. The present study represents the first investigation into the effect of age at onset of OCD on clinical characteristics and response to treatment in a paediatric sample.
Method: A total of 365 young people referred to a specialist OCD clinic were included in the study. Clinical records were used to examine potential differences in key clinical characteristics between those who had a very early onset of the disorder (before 10 years) and those who had a late onset (10 years or later). Group differences in treatment responsiveness were also examined within a subgroup that received cognitive behaviour therapy (CBT) alone or CBT plus medication (n = 109).
Results: The very early onset group were characterised by a longer duration of illness, higher rates of comorbid tics, more frequent ordering and repeating compulsions and greater parent-reported psychosocial difficulties. There were no differences in treatment response between the groups, and when age at onset was examined as a continuous variable, it did not correlate with treatment response.
Conclusions: Very early onset OCD may be associated with different symptoms and comorbidities compared with late onset OCD. However, these differences do not appear to impact on responsiveness to developmentally tailored CBT alone or in combination with medication. These findings further indicate the value in early detection and treatment of OCD in childhood.