A longitudinal evaluation of free will related cognitions in obsessive–compulsive disorder

BACKGROUND: Individuals with obsessive–compulsive disorder (OCD) often feel compelled to perform (compulsive) behaviors, thus raising questions regarding their free will beliefs and experiences. In the present study, we investigated if free will related cognitions (free will beliefs or experiences) differed between OCD patients and healthy subjects and whether these cognitions predicted symptom changes after a one-year follow up. METHODS: Sixty OCD outpatients were assessed for their beliefs in and experiences of free will at baseline and after one year of treatment. A subsample of 18 OCD patients had their beliefs compared to 18 age and gender matched healthy controls. A regression analysis was performed to investigate whether free will cognitions at baseline were able to predict long-term OCD severity scores. RESULTS: Patients with OCD and healthy controls do not seem to differ in terms of their beliefs in free will (U = 156.0; p = 0.864). Nonetheless, we found significant negative correlation between (i) duration of illness and strength of belief in determinism (ρ = -0.317; p = 0.016), (ii) age and perception of having alternative possibilities (ρ = -0.275; p = 0.038), and (iii) symptoms’ severity and perception of having alternative possibilities (ρ = -0.415; p = 0.001). On the other hand, the experience of being an owner of ones’ actions was positive correlated with the severity of symptoms (ρ = 0.538; p < 0.001) and were able to predict the severity of OCD symptoms at the follow up assessment. CONCLUSIONS: Older individuals or those with a greater severity of symptoms seem to have a perception of decreased free will. In addition, patients with a longer duration of illness tend to have a lower strength of belief in determinism. Finally, the experience of being the owner of the compulsions, along with the baseline severity of symptoms, can be a predictor of a worse outcome in the OCD sample. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12888-022-04108-6.