Nail biting and skin picking are not just mindless reflexes but survival mechanisms, according to clinical psychologist Dr Charlie Heriot-Maitland. In his new book, Controlled Explosions in Mental Health, he argues that these behaviours, often seen as unhygienic or painful, serve a protective function.
Dr Heriot-Maitland told The Independent that by creating a small sensation, the body can immediately focus physically, release tension, and gain a sense of control. This is preferable to dealing with overwhelming emotions that feel out of control. He explains that the brain, as a survival machine, prioritises predictability and would rather handle a known, controlled threat than face an unknown one.
The habit often starts in response to anxiety, boredom, or as a learned behaviour from parents. While there are practical tips to stop, such as cutting nails shorter or using anti-biting treatments, Dr Heriot-Maitland warns there are no quick fixes. Instead, he emphasises understanding the function of these behaviours and the fears they protect.
He categorises nail biting and skin picking as milder forms of self-harm, which he hopes will help people relate to and understand more stigmatised versions like cutting or eating disorders. By discussing these common habits, he aims to reduce stigma around self-harm in general.
