BackgroundSymptoms of obsessive-compulsive disorder (OCD) have been reported to increase during the COVID-19 lockdowns because of the hygiene requirements related to the pandemic. Patients with adjustment disorder (AD) may, in turn, represent a vulnerable population for identifiable stressors. In this study, we aimed at assessing potential symptoms changes in OCD patients during the lockdown in comparison with AD patients as well as versus healthy controls (HC).MethodsDuring the COVID-related lockdown, we enrolled 65 patients and 29 HC. Participants were tested with four clinical rating scales (Yale–Brown obsessive-compulsive scale and Brown Assessment of Beliefs Scale for OCD patients; Beck Depression Inventory-II and State–Trait Anxiety Inventory-Y for each group) that had been also administered just before the Italian lockdown.ResultsOur results showed that during the lockdown: (i) the symptoms of depression and anxiety increased in all groups, but this increase was most pronounced in HC (p< 0.001); (ii) OCD symptoms severity did not increase, but the insight worsened (p= 0.028); (iii) the proportion of OCD patients showing hygiene-related symptoms increased (p= 0.031 for obsessions of contamination), whereas that of patients with checking-related symptoms decreased.ConclusionsThe lockdown-induced psychological distress apparently changed the characteristics and the pattern of OCD symptoms expression but not their overall severity. This evidence confirms the heterogeneity and changing nature of OCD symptoms, strongly depending on the environmental circumstances.