Recent quotes:

A fear of feeling guilty might be key to some forms of OCD – Research Digest

“Guilt sensitivity may indeed cause individuals to be vigilant and sensitive to ways in which actions or inactions could potentially cause harm, performing checking compulsions in order to avoid, prevent, or neutralise the feared feeling of guilt,” the researchers said. This could have implications for therapy, they added, suggesting that in CBT, “cognitive restructuring should target not only inflated responsibility beliefs, but also beliefs concerning the intolerability and dangerousness of experiencing guilt.” Note, however, that the new findings were purely correlational so it’s not certain that guilt sensitivity causes OCD checking symptoms or if the symptoms lead to guilt sensitivity. It may be a bit of both. Or it’s even possible some unknown factors contribute to the symptoms and the guilt-sensitivity.

OCD patients' brains light up to reveal how compulsive habits develop -- ScienceDaily

In a study funded by the Wellcome Trust, researchers scanned the brains of 37 patients with OCD and 33 healthy controls (who did not have the disorder) while they repetitively performed a simple pedal-pressing behavioural response to avoid a mild electric shock to the wrist. The researchers found that patients with OCD were less capable of stopping these pedal-pressing habits, and this was linked to excessive brain activity in the caudate nucleus, a region that must fire correctly in order for us to control our habits. […]That the habits the researchers trained in these patients in the laboratory also triggered the caudate to over-fire adds weight to the suggestion that compulsions in OCD may be caused by the brain's habit system[…] "It's not just OCD; there are a range of human behaviours that are now considered examples of compulsivity, including drug and alcohol abuse and binge-eating," says Dr Gillan, now at New York University. "What all these behaviours have in common is the loss of top-down control, perhaps due to miscommunication between regions that control our habit and those such as the prefrontal cortex that normally help control volitional behaviour. As compulsive behaviours become more ingrained over time, our intentions play less and less of a role in what we actually do."