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Academic research can be hard to understand. SANE's Plain English research series translates important research into everyday language, to connect you with the latest information from the psychological field.
There is still much to learn about obsessive-compulsive disorder (OCD). Scientists have not been able to identify a clear cause, but believe that it is a mix of neurological, genetic, behavioural and cognitive factors. There is no evidence that stress alone causes OCD, although stressful situations such as abuse or neglect can trigger its onset.
Healthy people can experience obsessive-compulsive symptoms without being diagnosed with OCD, and people with other mental illnesses can experience obsessive-compulsive symptoms too. While some level of obsessive or compulsive thoughts or behaviours are normal in healthy people, certain events can trigger more concerning symptoms which may develop into fully-fledged OCD.
Researchers from the Karolinska Institute in Stockholm and King’s College in London looked at how stressful life events can affect the severity of OCD symptoms.
‘Are stressful life events causally related to the severity of obsessive-compulsive symptoms? A monozygotic twin difference study,’ by Pablo Vidal-Ribas, Arygris Stringaris, Christian Ruck, Eva Serlachius, Paul Lichtenstein, and David Mataix-Cols.
Published in February 2015 in European Psychiatry, the official journal of the European Psychiatry Association.
The researchers investigated whether stressful events exacerbate OCD symptoms, using identical twins as subjects to account for shared genetics, environment and upbringing.
The researchers found that two kinds of stressful events – physical abuse/neglect and sexual abuse – have the strongest effect on the severity of OCD symptoms. Overall, the study showed that physical and sexual abuse, family disruption and neglect can increase OCD symptoms.
In Sweden, there is a large study of twins born between 1959 and 1985 called STAGE (Study of Twin Adults: Genes and Environment). The researchers contacted twins who had been involved in STAGE, inviting them to participate in this new OCD research.
The group consisted of 22,084 twins (44,168 individuals), aged between 19 and 47.
The researchers asked the twins to report on whether they had experienced stressful life events, which were grouped into five categories: illness/injury, abuse/family neglect, loss, sexual abuse and non-sexual assault. The twins were then asked how many times the stressful event happened, and to rate each event’s impact.
They were also asked to report on their obsessive-compulsive symptoms, including how many times they experienced the symptoms and how severe the symptoms were. The researchers then analysed which life events led to obsessive-compulsive symptoms, and what impact they had.
Researchers found that:
In order to get a deeper understanding of the findings, the researchers analysed twins who had experienced different life events from one another. They found that people who reported emotional or physical neglect, physical abuse or exposure to family violence before the age of 18 scored higher in obsessive-compulsive symptoms than their non-exposed twin.
However, there was no difference in obsessive-compulsive symptoms between twins where one had experienced divorce of parents or had been adopted. This indicates that violence, abuse and neglect have a greater impact on obsessive-compulsive symptoms than family breakdowns or adoption.
Overall, abuse/family neglect and sexual abuse showed the most significant impact on OCD symptoms. Even when considering genetics, shared environment and shared upbringing, these life events played a key role in the severity of OCD symptoms.
There is a common myth that parenting styles or a child’s relationship with a parent can cause OCD. This research, however, suggests that abuse, neglect, family violence and sexual violence can have a negative effect at any stage of life. The researchers wrote that they are unaware of any studies investigating the link between stressful life events, parenting styles and OCD.
While stressful events which occur in childhood can contribute greatly to a person’s likelihood of developing OCD, it is also important to remember that the twins interviewed were aged 19 to 47. Many of the stressful events they reported may have occurred later in their lives.
Considering the results, the researchers wrote that more research is needed into how abuse and neglect can impact on mental health.
This SANE resource was created with support from The Vizard Foundation.