Mental illness can be associated with many dysfunctional beliefs or mental processes. A study published in PLOS One suggests that perfectionism is one such symptom that is especially prevalent in people with obsessive-compulsive disorder and in people with major depressive disorder.

Major depressive disorder (MDD) and obsessive-compulsive disorder (OCD) are two very serious and pervasive forms of mental illness. They are often comorbid and occur within the same individual. This is thought to be in part because there is overlap between the dysfunctional beliefs that occur in both of these mental illnesses.

One of these beliefs is perfectionism. This study seeks to explore the relationship between MDD and OCD and perfectionism using direct and indirect measures, predicting that the levels of perfectionism for both MDD and OCD will be similar due to similar underlying mechanisms.

For their study, Barbara Cludius and colleagues utilized 55 participants with OCD, 55 participants with MDD, and 64 healthy control participants. MDD participants were inpatient and OCD participants were recruited through psychiatric clinics. The Mini International Neuropsychiatric Interview was used to verify diagnoses and to make sure there were no diagnoses in the healthy controls.

Participants completed measures on depression, psychopathology, perfectionism, OCD, and demographics. Participants also completed a verbal intelligence test and the perfectionism IAT, which measured reaction times to a combination of words.

Results showed that patients with MDD and OCD showed higher levels of perfectionism than the healthy control group. This was true for both perfectionistic-strivings and perfectionistic-concerns. These results provided some support for a transdiagnostic process of perfectionism. While OCD and MDD groups did not differ on levels for perfectionistic-strivings, the OCD group showed higher levels of perfectionistic-concerns.

“Our results give further evidence, that perfectionistic concerns may be a transdiagnostic process which is similarly associated with MDD and OCD. Therefore, it may be helpful for those patients to receive specific treatments that focus on perfectionism,” the researchers wrote.

Patients with OCD and MDD performed similarly on the indirect SC-IAT perfectionism measure. Despite this, both groups also performed similarly to the healthy controls on this indirect measure. The SC-IAT only measures the perfectionistic strivings and future research could include a more expansive indirect measure.

“The indirect measure of perfectionism has given first evidence that the perfectionistic-strivings factor of perfectionism is not more pronounced in patients with MDD and OCD compared to healthy controls in the associative system,” the researchers said. “These results may suggest that contrary to cognitive models of the two disorders the perfectionistic-strivings factor of perfectionism is not as important.”

This study took steps into better understanding the similarities and differences in perfectionism across MDD and OCD patients. Despite this, there are limitations to note. One such limitation is the fact that the MDD group was pulled from inpatient settings while the OCD group was recruited from outpatient settings, which could indicate differences in severity.

The study, “Direct and indirect assessment of perfectionism in patients with depression and obsessive-compulsive disorder“, was authored by Barbara Cludius, Sarah Landmann, Anne-Katrin Külz, Keisuke Takano, Steffen Moritz, and Lena Jelinek.