I just found this jaw-dropping case study of a man who banged 11 nails into his head while sadly quite distressed and psychotic.

The X-ray images are striking on their own, and what is even more astounding is that he made a full recovery.

Penetrating head injury in planned and repetitive deliberate self-harm. Mayo Clinic Proceedings. 2007 May;82(5):536. Demetriades AK, Papadopoulos MC. 44-year-old man presented to his local emergency department wearing a baseball cap and complaining of headaches that had progressively worsened over the preceding 11 weeks. After we provided generous analgesia and performed simple investigations that failed to identify a diagnosis, the patient removed his cap to reveal an assortment of metallic objects embedded in his scalp. Plain radiographs showed 11 nails penetrating into his brain. A detailed history revealed a diagnosis of paranoid schizophrenia, and the patient confirmed that he had hammered a nail into his head each week for the past 11 weeks to rid him of evil. The nails were removed with the patient under general anesthesia, and he made an uncomplicated recovery with no neurological deficits.

Link to abstract on PubMed.