Obsessive Compulsive Disorder is often trivialised, but it is a debilitating condition for a lot of people.

Lily Bailey is an OCD sufferer who has written a book about it, Because We Are Bad. She describes it as an illness characterised by obsessive thoughts and compulsive behaviours in response to those thoughts.

"People talk about OCD as liking things to be tidy or neat, but it can be about anything. It can bring people to a dark place."

"If you're experiencing obsessions and compulsions, for it to be classified as OCD they have to be causing you quite a bit of distress."

Lily says she doesn't really remember a time when she didn't have OCD. As a child, it related more to checking things, and as she got older it became more about her thoughts. She feels it's difficult for those who don't have OCD to understand why it has such a strong effect on people's lives.

"When you have an obsession, it causes such a huge amount of anxiety that all you want to do is make that obsession go away."

Lily decided to write the book "because I was really frustrated by people misunderstanding what OCD is. People lose years of their lives because they don't understand what they have."

As to whether there is a cure for OCD, Lily doesn't think it's quite so clear cut.

"People are quite divided as to whether OCD ever goes away. What we do know is that everyone seems to be able to improve with the help of therapy and adequate treatment."