A Heightened Reactivity To Unlikely Threats Is A Key Sign Of Obsessive Compulsive Disorder, Shows New Research

A new paper published in the journal Clinical Psychological Science offers insight into why people with obsessive compulsive disorder engage in what psychologists refer to as “catastrophizing,” or the repeated mental simulation of unlikely catastrophic events. According to the researchers, it has to do with a flawed perception of the likelihood of low probability events.

“OCD-related obsessions are largely organized around fears of a specific harmful consequence that compulsions are enacted to prevent,” say the researchers led by Christopher Hunt of the University of Minnesota. “Virtually all common consequences associated with the major OCD subtypes possess two striking commonalities. First, most feared consequences in OCD are objectively catastrophic: the loss of one’s home, health, loved ones, or soul are among the costliest consequences imaginable. Second, the scenarios surrounding these catastrophic outcomes are often highly improbable.”

Examples of highly improbable catastrophic events that pervade the mind of someone with OCD fall into predictable categories, such as:

  • Contamination/washing (for example, “contracting a deadly infectious disease such as HIV from a public surface or becoming poisoned from contact with a household cleaner”)
  • Doubting/checking (e.g., “failing to prevent a fire, flood, or burglary after not checking stove tops, water taps, and locks or accidentally hitting and killing a pedestrian without knowing it”)
  • Aggressive OCD (e.g., “suddenly deciding to jump off a bridge or secretly and intentionally poisoning someone”)
  • Religious OCD (e.g., “being sent to hell for an immoral thought or trivial act or suddenly shouting obscenities in church”)
  • Sexual OCD (e.g., “acting on secret incestuous or homosexual desires”)
  • Somatic OCD (e.g., “failing to catch symptoms of a deadly disease, choking after not chewing food well enough, or going insane from continuously monitoring a bodily function”)

To test the idea that highly improbable events are viewed as more probable than they are by people with OCD, the researchers recruited 78 university students to participate in an in-person experiment. The researchers first measured participants’ levels of OCD using the 18-item OCI-R questionnaire. The OCI-R measures people’s overall levels of OCD as well as the OCD subtypes of washing, checking, ordering, obsessing, hoarding, and neutralizing.

The researchers then requested that participants play a video game in which they were a farmer with the objective of harvesting crops in an unpredictable environment. Participants made decisions in the game such as choosing to take a short, dangerous road versus a long, safe road to start planting their crops. Negative events, such as wild birds consuming one’s crops, were met with small electric shocks to the wrist. Participants’ expectations and reactions to negative outcomes in the game were measured by gauging their startle response (via an EMG electrode placed below the lower eyelid) as well as through self-reported anxiety and threat-probability ratings that were administered at different points during the game.

The researchers found that participants with OCD symptoms were more avoidant of low probability negative outcomes in the game. They state, “OCD did not confer a general tendency to avoid threat but, rather, a specific proclivity to avoid experimental analogues of improbable catastrophes.”

They also found that participants with OCD symptoms showed an increased startle response, as measured by eye-flinching, to low probability negative events. Such results, according to the researchers, offer initial experimental support for the observation that “a variety of common OCD presentations involve concerns with improbable catastrophic consequences and further implicate a more general sensitivity toward improbable threat as a candidate deficit driving this phenomenon.”

“The current study represents the first lab-based test of whether OCD is associated with an underlying sensitivity toward improbable catastrophic threats,” conclude the researchers. “Results show that individuals with higher OCD symptoms were more avoidant of potential threats that were both improbable and highly aversive and were also more expectant of and more physiologically reactive to improbable threats more generally.”

A full interview with Dr. Christopher Hunt discussing his research on obsessive compulsive disorder can be found here: Why people with OCD fear things they shouldn’t