Obsessive-compulsive disorder (OCD) is a severe and disabling malady that’s characterized by intrusive disturbing thoughts and repetitive behaviors to deal with these thoughts. Medications and psychotherapies may only partially help to diminish symptoms. OCD has some characteristics that are typical of anxiety disorders and others that are found in those with thought disorders.
Psychology Today’s recent article entitled “Obsessive-Compulsive Disorder and the Risk of Dementia” explains that many of the studies so far have been small and used a retrospective design. Recently, Mu-Hong Chen published a study in the Journal of Clinical Psychiatry that looked at a large insurance database in Taiwan to investigate this question. The results show that people with OCD may be at higher risk for developing dementias, such as Alzheimer’s disease and vascular dementia.
A universal single-payer health insurance system was instituted in Taiwan in the 1990s. By 2010, over 99% of its citizens were enrolled in the program. Chen used de-identified health information from a research database affiliated with this system to conduct the study. The researchers identified adults 45 and older who were diagnosed with OCD at least twice by board-certified psychiatrists between 1996 and 2013. None had a history of dementia prior to their OCD diagnosis. A matched group of control participants without OCD or dementia was determined on a 1:10 basis (10 controls were matched for every person with OCD). The final study included 1,347 individuals with OCD and 13,470 matched controls.
They reviewed records through 2013 and recorded diagnoses of dementia in people with OCD and matched controls without it. Dementia was considered to be present, if it was documented at least twice by board-certified psychiatrists or neurologists during the follow-up period. They controlled for potentially confounding variables, like age, sex, other medical conditions, income level and urbanization (using a scale related to urban versus rural living).
The results showed that during the follow-up period, 1.7% of those with OCD developed Alzheimer’s disease versus 0.1% of controls. Roughly 1.1% of those with OCD developed vascular dementia versus 0.2% of those in the control group. In addition, 3.6% of those with OCD developed unspecified dementia (such as dementia suggestive of Alzheimer’s disease together with co-existing vascular disease) versus 0.5% of controls.
After controlling for potentially contributing variables, the chances of a person with OCD developing dementia were more than four times higher than controls. In those with OCD, dementia was diagnosed about six years earlier than in those without OCD (70.5 years of age versus 76.7 years of age). In addition, early-onset dementias, defined as occurring before age 65, were more common in the OCD group (1.7% compared with 0.1%).
OCD occurs in about 1-2% of the population. Because it’s not that common, it would be difficult to see a relationship between OCD and dementia by studying all individuals with dementia.
Reference: Psychology Today (Dec. 13, 2021) “Obsessive-Compulsive Disorder and the Risk of Dementia”