Post-traumatic stress disorder
Definition
Post-traumatic stress disorder (PTSD) can occur after any major traumatic event.
Symptoms include upsetting thoughts and nightmares about the traumatic event, avoidance behaviour, numbing of general responsiveness, increased irritability, and hypervigilance.[1]
To fulfil the Diagnostic and Statistical Manual-IV (DSM-IV) criteria for PTSD:
An individual must have been exposed to a traumatic event
Have at least one re-experiencing, three avoidance, and two hyperarousal phenomena
Have had the symptoms for at least 1 month
The symptoms must cause clinically important distress or reduced day-to-day functioning.
It is labelled as acute for the first 3 months and chronic if it lasts beyond 3 months.[1]
People with subsyndromal PTSD have all the criteria for PTSD except one of the re-experiencing, avoidance, or hyperarousal phenomena.
Acute stress disorder occurs within the first month after a major traumatic event and requires the presence of symptoms for at least 2 days.
It is similar to PTSD, but dissociative symptoms are required to make the diagnosis.
Treatments for PTSD may have similar effects, regardless of the traumatic event that precipitated PTSD.
However, great caution should be applied when generalising from one type of trauma to another.
Risk Factors
Major trauma (such as rape)
A history of psychiatric disorders
Acute distress and depression after the trauma
Lack of social support
Personality factors.
Differential diagnosis
Epidemiology
One large cross-sectional study in the USA found that 1/10 (10%) women and 1/20 (5%) men experience PTSD at some stage in their lives.[2]
Aetiology
The cause of PTSD is unknown, but psychological, genetic, physical, and social factors are involved. PTSD changes the body’s response to stress.
It affects the stress hormones and chemicals that carry information between the nerves (neurotransmitters).
Having been exposed to trauma in the past may increase the risk of PTSD.
Clinical features
Repeated "reliving" of the event, which disturbs day-to-day activity
Flashback episodes, where the event seems to be happening again and again
Recurrent distressing memories of the event
Repeated dreams of the event
Physical reactions to situations that remind you of the traumatic event
Avoidance
Emotional "numbing," or feeling as though you don’t care about anything
Feelings of detachment
Inability to remember important aspects of the trauma
Lack of interest in normal activities
Less expression of moods
Staying away from places, people, or objects that remind you of the event
Sense of having no future
Arousal
Difficulty concentrating
Exaggerated response to things that startle you
Excess awareness (hypervigilance)
Irritability or outbursts of anger
Sleeping difficulties
May also feel a sense of guilt about the event (including "survivor guilt"), and the following symptoms, which are typical of anxiety, stress, and tension:
Agitation, or excitability
Dizziness
Fainting
Feeling your heart beat in your chest (palpitations)
Fever
Headache
Paleness
Pathophysiology
PTSD displays biochemical changes in the brain and body that differ from other psychiatric disorders such as major depression.
Individuals diagnosed with PTSD respond more strongly to a dexamethasone suppression test than individuals diagnosed with clinical depression.[17][18]
In addition, most people with PTSD also show a low secretion of cortisol and high secretion of catecholamines in urine, with a norepinephrine/cortisol ratio consequently higher than comparable non-diagnosed individuals.[19]
This is in contrast to the normative fight-or-flight response, in which both catecholamine and cortisol levels are elevated after exposure to a stressor.[20]
Brain catecholamine levels are low,[21] and corticotropin-releasing factor (CRF) concentrations are high.[22][23]
Together, these findings suggest abnormality in the hypothalamic-pituitary-adrenal (HPA) axis.
Given the strong cortisol suppression to dexamethasone in PTSD, HPA axis abnormalities are likely predicated on strong negative feedback inhibition of cortisol, itself likely due to an increased sensitivity of glucocorticoid receptors.[24]
Some researchers have associated the response to stress in PTSD with long-term exposure to high levels of norepinephrine and low levels of cortisol, a pattern associated with improved learning in animals
Translating this reaction to human conditions gives a pathophysiological explanation for PTSD by a maladaptive learning pathway to fear response through a hypersensitive, hyperreactive and hyperresponsive HPA axis.[25]
Low cortisol levels may predispose individuals to PTSD
Because cortisol is normally important in restoring homeostasis after the stress response, it is thought that trauma survivors with low cortisol experience a poorly contained—that is, longer and more distressing—response, setting the stage for PTSD.
There is considerable controversy within the medical community regarding the neurobiology of PTSD.
A review of existing studies on this subject showed no clear relationship between cortisol levels and PTSD.
Only a slight majority have found a decrease in cortisol levels while others have found no effect or even an increase.[27]
Three areas of the brain whose function may be altered in PTSD have been identified
In human studies, the amygdala has been shown to be strongly involved in the formation of emotional memories, especially fear-related memories.
The amygdalocentric model of PTSD proposes that it is associated with hyperarousal of the amygdala and insufficient top-down control by the medial prefrontal cortex and the hippocampus particularly during extinction.[33]
This is consistent with an interpretation of PTSD as a syndrome of deficient extinction ability.[33][34]
Further animal and clinical research into the amygdala and fear conditioning may suggest additional treatments for the condition.
Investigations
There are no tests that can be done to diagnose PTSD.
The diagnosis is made based on a set of symptoms that continue after extreme trauma.
Management
a) conservative
Early detection
Preventative treatments
Early debriefing
Psychobiological treatments
Stepped collaborative care
Counselling
CBT
Eye movement desensitization and reprocessing
Interpersonal psychotherapy
b) medical
c) surgical
n/a
Prognosis
One large cross-sectional study in the USA found that over a third of people with previous PTSD continued to satisfy the criteria for PTSD 6 years after initial diagnosis.[2]
However, cross-sectional studies provide weak evidence about prognosis.