It is important to distinguish between acute trauma in adulthood, such as a natural disaster or an assault, and chronic trauma that occurs in childhood, such as ongoing sexual or physical abuse. Trauma in general has been associated with anxiety, depression, increased drinking, anger outbursts, suicidal behavior, and a syndrome known as post-traumatic stress disorder (PTSD). While personality in adulthood is largely formed, personality is still developing in childhood. Thus, chronic trauma in childhood can have extremely pervasive and long-term effects on personality development.

People with histories of serious childhood abuse can develop severe personality disorders. They can also develop self-injurious behaviors, in which they may cut or burn themselves. Dissociative symptoms are also fairly common. These involve feelings of unreality and disconnection from mental and physical experience. There is a striking lack of awareness of certain feelings, thoughts, or actions. In extreme cases, people might develop dissociative identity disorder (previously known as multiple personality disorder), in which they literally believe that they have several different personalities within their own body.