A large Danish study involving more than 850,000 people supports earlier evidence that OCD (obsessive-compulsive disorder) and autism have common genetic roots.
Individuals with autism are twice as likely to get an OCD diagnosis, when compared to their non-autistic peers, and those with OCD are four times more likely to also be diagnosed with autism. Plus, children are at significantly higher risk for autism when a parent has OCD. These findings were published in PLOS ONE last November (2016).
Data for the study were drawn from the Danish Psychiatric Central Research Register that contains the past 47 years of Denmark’s psychiatric care records.
After analyzing the data, lead researcher Sandra Meier and her colleagues identified 18,184 individuals with autism, 11,209 with OCD, and 739 who had both. Of those with both conditions, 205 were given both diagnoses simultaneously, 253 were first diagnosed with autism, and 281 received the OCD diagnosis initially.
The investigators were surprised that almost one-third of the children with both conditions were diagnosed with OCD first, since OCD symptoms typically develop later in life than symptoms of autism. This implies that kids with OCD may demonstrate subtle autism signs that go unnoticed for years, and are maybe recognized when OCD treatments fail.
The researchers also note that an OCD diagnosis is usually made after a patient describes having obsessive thoughts. So, children diagnosed with OCD are less likely to have severe autism with a cognitive impairment that inhibits verbal expression.
Despite some symptom differences, the overlap between autism and OCD - including the reliance on repetitive behaviors to relieve anxiety - suggests a shared genetic base. This commonality could mean that a treatment effective for one of these disorders, could also benefit the other.
Source: Spectrum News
Photo credit: Lance Neilson