Head injury and traumatic brain injury (TBI) are both fairly common conditions that can result in a variety of problems and symptoms such as dementia and psychosis. To a psychiatrist, these mental impairments are known as neurobehavioral deficits and include impairment in emotions, memory, cognition, and accompanying behavior.

Psychosis is a generic term that lumps together many more specific symptoms and is never meant to be a self-contained diagnosis. Psychosis always occurs for a particular reason, such as TBI, and includes the more detailed symptoms of:

• Hallucinations
• Delusions
• Paranoia
• Personality changes
• Disorganized thinking
• Difficulty in social interactions
• Lack of awareness that behavior is unusual

Traumatic brain injury is just one of many causes of psychosis. Psychosis can also be caused by drug use or other psychological conditions such as schizophrenia. Psychosis varies in duration from person to person and from episode to episode. Some patients can recover from an episode of psychosis spontaneously in a just a few minutes. Others require hospitalization and manic periods can last for weeks at a time.

Although psychosis is known to be caused by brain injury, modern brain scanning technology has not always provided results or insights into the exact nature or cause of the psychosis. One study in 2003 found a correlation in reduced gray matter in the cortex of those suffering from psychosis. In other studies, there is no detectable brain injury remaining yet psychosis persists. Some doctors believe that physical brain changes may be related to the length of psychotic episodes but no solid proof exists. It may very well be true that there is no physical cause of psychosis but a physical episode can trigger a deeply-rooted psychological impairment that causes the onset of the episodes. Some scans, however, have determined that there are physical events taking place during symptoms like hallucinations. For example, auditory hallucinations are accompanied by stimulation in the auditory cortex. Persons with psychosis do show increased activity in the right hemisphere of the brain. Curiously, this area of the brain shows the same stimulation among people who hold strong beliefs in the paranormal and those who report mystical experiences. More studies are needed to determine the exact, if any, physical causes of psychosis.

Psychotic episodes are significantly affected by mood and each one is characterized by different combinations of more specific symptoms. A psychotic episode can contain visual or auditory hallucinations. Hallucinations are a misperception of stimuli that may or may not exist and manifest seeing objects or lights and possibly hearing voices or other sounds. Delusions may also be a part of psychosis. Delusions are a misperception of the state or circumstances surrounding an individual. Delusions differ from hallucinations in that delusions are not related to the senses. Several different types of thought disorder are also possible. Those affected by psychosis may have problems speaking or writing. Others have difficulty holding onto their train of thought, switching topics suddenly. This can be accompanied by mild amnesia.

The most telling symptom of psychosis is called “lack of insight.” People suffering from the symptoms of psychosis are not aware that they are behaving in an unusual manner. No matter how outrageous the hallucinations or delusions may be, the person does not see them as unrealistic in any way. Not everyone with psychosis has the lack of insight. Also, the level and length of the lack of insight can vary in each individual.

Psychosis-inducing traumatic brain injury occurs when the head strikes an outside object with a force that shakes the brain violently within the skull. In some cases, it is possible for the skull to break. Although most brain injuries are due to this interaction of brain and skull, in some open head injuries foreign objects may be introduced into the brain. When the jarring of the brain takes place, tissue can be torn and bruised. Blood vessels and membranes may also be damaged, causing further injury. There are two main factors in the severity of the brain injury – the force of the blow and the location. It is possible that injury-induced psychosis will end when the brain heals but sometimes the episodes can continue for long afterward. Also, direct brain damage may not always be the primary cause of psychosis. Internal bleeding and collection of fluid in the skull can put pressure on the brain and infections can also result that can cause psychotic episodes.

Some related facts about brain injury and psychosis or dementia:

• Up to 500,000 people per year are hospitalized in the U.S. for head injuries.
• Younger people are likely to receive head injuries.
• Older people with head injuries are more likely to develop psychosis as a result.
• Men are more likely than women to sustain head injuries.

Common causes of head injuries include:

• Motorized vehicle (automobile, motorcycle, ATV, etc.) accidents – 50%
• Falls – 21%
• Assault/gunshot – 12%
• Sports/recreation – 10%

There are also several demographical differences in those who suffer from brain injuries:

• Infants – primarily from abuse such as shaken baby syndrome
• Children – bicycle accidents are one of the top causes
• Elderly – brain injury usually caused by falling

Psychosis is not the only symptom of TBI. Psychotic episodes are often accompanied by one or more of the following:

• Memory loss
• Irritability
• Mood swings
• Restlessness
• Insomnia
• Headache
• Fatigue
• Apathy
• Depression