The results suggest that traumatic brain injury may cause decades-lasting vulnerability to psychiatric illness in some individuals. Traumatic brain injury seems to make patients particularly susceptible to depressive episodes, delusional disorder, and personality disturbances. The high rate of psychiatric disorders found in this study emphasizes the importance of psychiatric follow-up after traumatic brain injury.

Most of the patients had mild cognitive decline during the follow-up, but this decline was influenced by gender and age at injury. Unlike the long-term course in the other domains of cognition, semantic memory showed good recovery potential after traumatic brain injury (TBI). The profile of long-term cognitive decline after TBI seems to be qualitatively different from the early signs of dementia of the Alzheimer type.

The results show that long-term memory impairments after TBI are associated with MRI volumetric measures. This suggests that the degree of diffuse injury leading to atrophic changes is prognostically more important than the initial severity of TBI.

Significant traumatic brain injury (TBI) is nearly always associated with cognitive deficits, but in a highly variable manner. Apolipoprotein E (ApoE) plays a pivotal role in CNS response to injury. To examine the association of ApoE genotype with long-term outcome in TBI patients, we determined the ApoE genotype from 61 TBI patients who had been injured over three decades earlier. All patients had been studied neuropsychologically after their injuries. The long-term outcome was evaluated with repeated neuropsychological testing and by applying various measures of everyday functioning and quality of life. After three decades, TBI patients with the ApoE epsilon4 allele showed significantly poorer general cognitive level than those without this allele. This decline was wholly accounted for by a subgroup of these patients who had developed incident or clinical dementia, while the majority of the ApoE epsilon4 positive patients showed no decline at all. The other outcome measures describing vocational, physical, or subjective symptom outcome did not show significant relationships to the ApoE genotype. A portion of the TBI patients with the ApoE epsilon4 allele seem to be at risk of long-term cognitive decline.

Alexithymia is common, along with psychiatric disorders, in patients with TBI. Both of them may reflect dysfunction of the injured brain. In clinical practice, alexithymic features should be taken into consideration in psychosocial rehabilitation after TBI.