From the Abstract:
"Adverse Childhood Experiences (ACEs) such as child abuse are related to poor health outcomes. Spanking has indicated a similar association with health outcomes, but to date has not been considered an ACE". The research has taken spanking and attempted to see whether adult health problems can be associated with childhood experiences of spanking. Adult mental health problems included depressive affect, suicide attempts, moderate to heavy drinking, and street drug use. The study concludes that "spanking is empirically similar to physical and emotional abuse and including spanking with abuse adds to our understanding of these mental health problems". Based on this, 'spanking should also be considered an ACE and addressed in efforts to prevent violence."