Introduction
Traumatic brain injury (TBI) is known as “silent epidemic” because of lack of knowledge
about it and its delayed symptoms of memory and cognitive problems. The incidence
is approximately 1.4 million per year in the United States,[1] and in the developing countries, it is approximately 341 per 100,000. In the United
States, the annual productivity loss due to TBI and its delayed effects is more than
$56 billion.[2] TBIs occur mainly due to traffic accidents and falls.[3] All the age groups are affected, but the rates are higher in men than in women.
The causes vary as per the age groups as traumas affect mainly children and elderly,
and traffic accidents and violence affect more of adolescents and young adults.[3] Data from various studies indicate wide variation in the incidence and prevalence
of psychiatric disorders after TBI, but they are definitely higher as compared with
general population. Therefore, this review was undertaken to assess the psychosocial
impact of brain injury on an individual.
Also, the unpublished data of 56 TBI cases at our university hospital with 3 weeks
to 9 months follow-up revealed that 30 (53.5%) of 56 patients had one or other psychiatric
disorders. This incidence seems to be very high and is important because our university
catches patients from rural areas of Uttar Pradesh; thus, it appears that the people
in rural areas are more vulnerable for emotional and psychological disturbances.
Impact on Individual
Depression
The incidence rate of depression post TBI vary from 15.3 to 33% and prevalence rate
from 18.5 to 61%.[4] Symptoms vary from transitory responses to stressing situations to pathologic conditions,
and also there is coexistence of symptoms of depression, adjustment disorder, and
grief.[5] Also, it is difficult to differentiate somatic symptoms of depression from symptoms
directly caused by TBI. The symptoms include fatigue, less involvement in activities,
insomnia, decreased appetite, and concentration.[6]
Depression after TBI may occur due to reduction in left prefrontal gray matter volume,[7] lesions in dorsolateral prefrontal cortex and left basal ganglia,[8] and also in lateral and medial frontal lobe,[9] leading to rupture of neural circuits of the prefrontal cortex, amygdala, hippocampus,
basal ganglia, and thalamus. This leads to mood disorders[10] and also the low levels of serotonin encountered after TBI may cause emotional changes,
disinhibition, and aggression seen after TBI. The lesion in hippocampus and alteration
in its morphology has also been reported in cognitive and depressive disorders.[11]
[12]
Poorer social functioning,[8]
[13] high levels of work dissatisfaction, unemployment,[7]
[14]
[15] low economic status,[7] less education,[15] and lack of close personal relationships[13] have been reported in patients who develop depression following TBI. Also, psychiatric
comorbidity is common in depression after TBI. Frequently depression and anxiety coexist
mainly related to injuries in the right hemisphere.[16] Isolated depression was more in lesions in the anterior areas on the left.[7] Also in our findings, 3 of our 28 cases having left-sided lesions had depression
whereas 4 had behavioral disorders, and further, the behavioral disorders and depression
coexisted in 2. However, 1 of 17 right-sided lesions had depression. Thus, it appears
that psychiatric disorders are encountered more in left-sided lesions as compared
with right.
Mania
The reported prevalence is 4.2% for mania directly caused by TBI[17] and increases to 9% within 12 months of follow-up.[18] The symptoms include aggression, irritable moods, and euphoria.[19] It is associated with lesions in the temporal basal poles and orbitofrontal cortex
mainly in the right hemisphere.[18]
[19]
[20]
[21] Also, it has been reported that there are focal lesions in areas connected to the
limbic system in the right hemisphere, or anterior subcortical atrophy, lack of inhibitory
function of the frontal cortex on subcortical limbic structures due to abnormalities
in these circuits.[22] The bipolar disorders are common following TBI.[23]
In our study, mania was not documented in any of the 30 cases, although there were
four pure temporal lesions, two on either side barring frontotemporal which were six.
Obsessive-Compulsive Disorder
The prevalence varies between 0.7 and 1.6% and is similar to the general population.[17] The main symptoms include obsessive slowness and compulsive exercise practice. Patients
with obsessive slowness had compromised performance in neuropsychological tests for
executive function, memory, and language.[24]
[25] Obsessive-compulsive disorders (OCDs) are mainly related to lesions in frontal and
subcortical areas, mainly the orbitofrontal cortex, caudate nucleus, and anterior
cingulate cortex.[25]
[26]
There is lack of study related to psychosocial factors in OCD after TBI. It is a condition
with a biological basis, but it disrupts the rehabilitation process. Psychiatric comorbidity
is common in patients with OCD after TBI.[27]
Posttraumatic Stress Disorder
The reported prevalence is 13.9% in post TBI cases mainly influenced by the severity
of TBI and posttraumatic amnesia due to the formation of pathologic memories. Posttraumatic
stress disorder (PTSD) symptoms were not reported in patients who had brief episode
of unconsciousness and but had developed amnesia after TBI.[28]
[29]
[30] The increase in the astrocytic protein S-100B has been reported in PTSD cases following
TBI 1 year later[31] in patients in whom traumatic memories involved amygdala, hippocampus, and other
related structures.[32]
Patients with post TBI PTSD had reduced quality of life, poorer productivity functioning,[33] and reduced insight.[34] Also, the comorbidity with depression and anxiety is common in PTSD after TBI.[33]
[34]
[35]
[36]
Psychotic Disorders
Post TBI psychosis is rare, and the reported incidence is 0.1 to 9.8%.[37] The studies revealed that psychotic patients are more predisposed to suffer trauma[38] and genetic background for schizophrenia increases this.[39] In the acute phase of TBI, the psychotic symptoms are delirium, delusions, reference,
control, and grandiosity[40] whereas the hallucinations appeared later (i.e., > 2 years after the TBI) and may
be auditory or visual. Aggressive behavior along with negative symptoms, disorganization,
and catatonia were also reported. Prodrome symptoms include depression, antisocial
and inappropriate social behavior, social withdrawal, and deterioration at work.[41]
Post TBI psychoses had electroencephalographic abnormalities in the temporal lobes
that may be accompanied with seizures,[42] also the focal lesions or brain atrophy in the frontal and temporal lobes.[40]
[41]
[42]
[43]
[44] The increased susceptibility has been reported in patients with neurologic diseases
or previous TBI.[42]
The psychotic symptoms result from impairment of neural circuits in the frontal and
the temporal lobes, leading to an increase in the temporal limbic activity. There
is lack of studies related to psychosocial factors in psychosis after TBI.[45]
Disorders Related to Alcohol
Alcohol is a psychoactive substance and is a leading cause of traffic accidents, falls,
and violence leading to TBI. Alcohol dependence was reported in 24.1% and abuse in
10.8% of the TBI cases.[46] The brain atrophy has been reported in TBI patients with history of moderate or
heavy use of alcohol[47] along with reduction in prefrontal gray matter volume.[10] The neuronal loss related to alcohol has been reported in the frontal cortex, hypothalamus,
cerebellum, hippocampus, amygdale, and locus coeruleus.[48]
Traumatic brain injury and alcohol use individually produced mild alterations in event-related
potential testing, but changes were greater when both conditions coexist.[49]
Also, patients who did not sustain abstinence after TBI had more mood disorders[10] whereas depression, anxiety, suicidal thoughts, violent behavior, difficulties for
concentration, and use of cannabis were reported in the individuals with previous
TBI along with higher rates of depressive and anxiety symptoms, antisocial personality,
and suicidal attempts.[50]
[51]
Personality Changes
Apathy
Apathy means disorders of decreased motivation, abulia, and akinetic mutism. The incidence
varies from 10 to 46.4%.[52]
[53] It is mainly seen in the lesions involving the subcortical areas or right hemisphere,
causing damage to cortico-striatal-pallidal-thalamic pathways involving the anterior
cingulate cortex, accumbens nucleus, ventral pallidum, and medial dorsal thalamic
nucleus, which are the mediators of motivation leading to akinetic mutism, abulia,
and apathy.[54] Further, the orbitofrontal cortex, amygdala, hippocampus, and tegmental ventral
area are also involved in the motivational state related to rewards. Lesions in these
structures also produce apathetic symptoms. Dopamine is the main neurotransmitter
linked to apathy as it has role in the mechanisms of novelty seeking, reward, and
response to unexpected events.[55]
Affective Lability
These include emotional instability or rapid mood changes, involuntary emotional expression
disorder, and pathologic laughing and crying,[56] which is unrelated to the subjacent mood or independent from usual provoking stimuli.[55]
[57] Also associated are aggression and anxiety in the left-sided frontal lobe lesions.
It has been reported that impairment of cerebro-ponto-cerebellar pathways leads to
incapability of the cerebellar structures to get adjusted to the execution of laughing
or crying according to the environmental stimuli, thus leading to inappropriate or
chaotic emotional expression.[58] The various neurotransmitters involved in these expressions are serotonin, dopamine,
and glutamate.[59]
Aggression
Aggression is damaging, threatening, or intimidating behavior that may be impulsive
or premeditated or episodic dyscontrol, with recurrent crises of out-of-proportion
fury due to provocation or frustration[60]
[61] along with the antisocial behavior with-the inconsideration for moral and social
principles.[62]
[63] The main characteristics of aggression after TBI are impulsivity and anger[64] with the incidence of 14.4 to 33.7%.[16]
[65] Also, it is associated with substance abuse, male sex, TBI severity, intelligence
level, and low socioeconomic status.[5]
[66]
[67]
[68]
[69]
[70]
The impulsive aggression may result from failure to regulate negative emotions, such
as anger. Threatening environmental stimuli are transmitted to amygdala, from where
they are relayed to the basal ganglia where they are integrated with social information
from the orbitofrontal cortex. The behavioral responses are then initiated through
projections toward the other cortical areas, hypothalamus, or brainstem. The orbitofrontal
cortex, dorsolateral prefrontal cortex, and anterior cingulate cortex inhibit the
activity of amygdala, thus forming a regulatory mechanism that is lost in patients
with injuries in these areas leading to the propensity to impulsive aggression.[71] The studies have reported the role of serotonin in aggressive behavior[62]
[72] along with polymorphisms in the tryptophan-hydroxylase enzyme gene.[71]
Other Personality Changes
The personality changes reported in post TBI cases are behavioral disinhibition, aberrant
sexual behavior, hypersexuality, moria, and self-awareness impairment.[21]
[73]
[74]
[75] These are attributed to the frontal lobe impairment as it modulates the primary
responses that come from other regions, such as the limbic system and motor cortex.[20]
Conclusion
Reviews of various studies reveal that TBI affects the individual adversely psychosocially.
We also noted different psychiatric disorders in post head injury cases during their
follow-up, which included depression, behavioral disorders, cognitive disorders, memory
impairment, anxiety disorders, stress-related headache, vertigo, irritability and
sleep disorders, etc. The incidence was as high as 53.5% in a rural university catering
mainly rural population.
In the Indian context, TBI and psychiatric disorders related to it have special importance
as the road traffic accidents are higher in India, so psychiatric disorder follow-up
is also common. Main psychiatric disorders are impulsive or irritable behavior followed
by cognitive changes, depression, and behavioral problems that may be stress related.
Often, these things are ignored, which may hamper productivity of the country. A detailed
analysis with well-planned study will reveal better outcome.
