Traumatic brain injury (TBI) is a significant cause of disability in the United States, with an incidence of about 1.5 million cases per year (National Institutes of Health Consensus Development Panel, 1999). It is associated with both neurologic and psychiatric consequences. Although the neurologic problems usually stabilize with time, the psychiatric disorders often continue to remit and relapse. Factors associated with the development of psychiatric disorders include older age, arteriosclerosis, and chronic alcoholism, all of which interfere with the reparative process within the central nervous system. Other contributors to psychiatric disability include a pre-TBI history of psychiatric illness, illicit drug abuse, and lack of social support. Because post-TBI psychiatric disturbances interfere with rehabilitation and cause emotional and financial burden for patients and caregivers, early diagnosis and treatment are important. Post-TBI psychiatric disturbances are best classified according to their clinical presentation. These disturbances are discussed below and their pharmacologic and nonpharmacologic treatment strategies are recommended. The mood disturbances most commonly associated with TBI are major depression, mania, anxiety, and apathy. Major depression is seen in about 25% of people with TBI. Symptoms of major depression include persistent sadness; guilt; feelings of worthlessness; hopelessness; suicidal thoughts; anhedonia; and changes in patterns of sleep, appetite, and energy. Sometimes these symptoms may be associated with psychotic features such as delusions and hallucinations. It is important to remember that changes in sleep, appetite, or energy are not specific to the syndrome of major depression and may be due to the brain injury itself, or to the noise, stimulation, or deconditioning associated with hospitalization. If due to the latter conditions, gradual improvement occurs with time in most patients. Sadness in excess of the severity of injury and poor participation in rehabilitation are strong indicators of the presence of major depression. The presence of poor social functioning pre-TBI and left dorsolateral frontal and/or left basal ganglia lesion have been associated with an increased probability of developing major depression following brain injury ( Jorge et al., 1993a; Jorge et al., 2004). Major depression should be differentiated from demoralization, primary apathy syndrome, and pathologic crying.
Long-Term Cognitive Impairments and Pathological Alterations in a Mouse Model of Repetitive Mild Traumatic Brain Injury
