Guilt is an important factor in perpetuating obsessive–compulsive disorder symptoms. Research is mixed on the possible connection between Catholicism and obsessive-compulsive symptoms. A study of 165 individuals by the University of Parma found that religious individuals scored higher on measures of control of thoughts and overimportance of thoughts, and that these measures were associated with obsessive-compulsive symptoms only in the religious participants. Another study noted a link between intrinsic religiosity and obsessive–compulsive cognitions/behaviors only among Catholic participants. However, a study from Boston University found that no particular religion was more common among OCD patients, and that OCD patients were no more religious than other subjects with anxiety. Religious obsessions were connected to the participants' religiosity, but sexual and aggressive symptoms were not. Greater religious devotion among OCD patients was correlated with increased guilt.