A 44 year old man was referred to the accident and emergency department by the psychiatric services, having claimed to have hammered several nails through his skull over a three month period. The patient had a long history of depression, personality disorder, and previous deliberate self-harm. He had remained well throughout this period and had been cleaning the wounds with weak antiseptic on a regular basis. He had concealed the injuries by wearing a hat. Two days prior to admission he had inserted a much larger 12.7 cm (5 inch) masonry nail and had developed left sided weakness and unsteadiness of …