Green’s Dictionary of Slang

psychotic, emotionally unstable; emotionally demanding; also as n.

1973		L. Shecter On the Pad 272: After many head-banging sessions with the tape recorder he finally admitted: ‘Yeah [...] The money was for fucking around’.
1991		M.B. ‘Chopper’ Read Chopper From The Inside 140: Julian is no cold-blooded killer, nor is he a head-banging psychotic.
2004		R.G. Barrett Rosa Marie’s Baby (2013) [ebook] It was all ‘Oi, oi, oi’ head-banging, loud and fast.