Clear evidence of impaired thought processes can be detected in children at risk of later developing Obsessive Compulsive Disorder (OCD), two new psychological studies have found.
The studies are the first to confirm that such signs can be predictive of adult OCD, raising hopes that therapists may be able to intervene before the disorder develops fully.
Children between the ages of nine and 12 who went on to develop the disorder were found to have had difficulty with visuomotor skills (performing physical activities that depend on sight, such as writing) and visuospatial tasks (such as assembling jigsaw puzzles or placing pegs into a board).
Without effective therapy - which succeeds for between two-thirds and three-quarters of those treated - the disorder can overwhelm everyday life for adult sufferers, notes one of the authors of the study, Dr Jessica Grisham, a lecturer in the UNSW School of Psychology.
"In 2005, the World Health Organisation ranked it among the 10 leading causes of global disability," says Dr Grisham. People with OCD may obsess about hygiene and spend many hours in the bathroom; some may be consumed with fear that their loved ones will meet a grisly end; and others may refuse to go through certain doorways or need to knock or tap something repeatedly.
The new findings - published in the American Journal of Psychiatry (AJP) and a forthcoming article in the British Journal of Psychiatry (BJP) - are based on the Dunedin Study, a unique longitudinal research project following the life progress of more than 1,000 randomly selected children born in Dunedin, New Zealand, in 1972-73.
In the AJP report, the authors noted that at age 32, about 2% of the 700 continuing Dunedin participants met the formal diagnostic criteria for OCD. They estimate that between a fifth and quarter of the population have obsessions or compulsions that meet at least some of the diagnostic criteria. About a third of them also have another anxiety disorder or depression.
The causes of OCD are still unclear: it can run in families, suggesting a genetic component, but it can also follow from traumatic experiences.
In the BJP paper, the authors checked the childhood tests of the OCD group and found that they performed poorly in visuospatial, visuomotor ability and non-verbal memory. But they performed normally on tests of verbal comprehension, verbal fluency, and verbal memory: "The results suggest there is a pattern of specific deficits associated with OCD, rather than overall cognitive or neuropsychological impairment," the researchers say.
Dr Grisham cautions that the number of participants with OCD is small and that not all those with relevant childhood deficits developed OCD. "But the Dunedin Study has shown us that obsessions and compulsions are common in the adult population and that they have their roots in childhood.
"Parents should not be overly concerned, however. It's normal for children to have little rituals, such as flipping a light switch or not stepping on a crack. That's just part of childhood, and most people grow out of it. It's when it becomes distressing to the child - when children speak up and say they're bothered by their own thoughts or behaviours or when the behaviours interfere with the child's daily routine - that parents should take notice."
The researchers are currently seeking adults within travelling distance to UNSW to take part in ongoing research projects about OCD. Anyone interested should contact the project manager, Dr Alishia Williams on 0405 444 795.
Media contacts: Dr Grisham email@example.com
Bob Beale (UNSW Faculty of Science) 0411 705 435 firstname.lastname@example.org