We have probably all heard someone say they are “a little bit OCD,” perhaps jokily or as a matter of pride, in reference to their meticulous rearrangement of their bookshelves or habit of spending rather too long cleaning their bathroom.

Most of us have a rough idea of what obsessive-compulsive disorder is, but it tends to be viewed as a behavioural quirk. In fact, this condition – characterized by intrusive thoughts and compulsive actions that you can’t stop – is debilitating for the 1 to 3 per cent of the global population it affects. In this light, quips about being “a little bit OCD” risk trivializing a condition that can be every bit as serious as schizophrenia or depression. The misuse of the term might reflect our ignorance about OCD. But as we explore in “A fresh understanding of OCD is opening routes to new treatments,” we are now discovering more about the mechanisms in the brain – with implications for how we think about the condition.

It is true that a degree of obsessiveness and compulsive behaviour is present in all of us. We go back to check that we locked the front door, and we can’t stop our mind wandering to a looming stressful event. In fact, many OCD symptoms seem to represent distortions of useful behaviours. But imagine if the intrusive thoughts and urges to take action didn’t stop? That is what characterises OCD.

Thanks to decades of research into the underlying mechanisms behind the condition, we now know that entire brain networks are affected, with significant imbalances in the neurotransmitters that drive the transmission of signals around them. We are also learning that it is a more complex condition than we thought, with the immune system and perhaps even microbes in the gut playing a part.

These insights into the drivers of OCD in the body and brain are opening the way to new treatments, which are sorely needed for those who don’t respond to the current first-line therapies. What is abundantly clear, however, is that OCD is a profoundly distressing condition that we are just beginning to get to grips with. It is past time we stopped with the quips.