In the state of California, there are patients who suffer changes in mood or the inability to control their mood following a brain injury. This is a common symptom of a traumatic brain injury and may be temporary or permanent, depending on the severity of the brain injury. People who have experienced a brain injury may also become physically violent in conjunction with their mood swings.

When specific areas of the brain are damaged, specifically the frontal and temporal lobes, hippocampus and amydgala, the results may be volatile emotions, high volatility, verbal attacks on friends and loved ones, and an impairment of normal impulse control. The problems may only occur occasionally, or they may be repetitive, affecting relationships with others.

Brain injury can lead to psychiatric issues like anxiety and depression. Some victims of brain injury develop obsessive compulsive disorder. Some patients may be aware of their changes in mood and their inability to control their thoughts and reactions. Others may not be aware that anything has changed.

Loved ones of victims of brain injury who are experiencing personality changes often report changes of their own. Loved ones may become withdrawn, look for new ways to resolve conflict and experience decreased intimacy. Brain injury affects more than just the victim. It is recommended that those close to a victim of brain injury who is dealing with unstable moods seek professional advice for offering care for their loved one and for themselves as well.