Post-Traumatic Stress Disorder (PTSD) is a psychiatric condition that can develop in some individuals following exposure to a traumatic event, such as actual or threatened death, serious injury, or sexual violence. This includes directly experiencing the event, witnessing it, learning about it happening to a close loved one, or experiencing repeated exposure to aversive details, such as in professional duties. Current clinical understanding groups the criteria into four distinct clusters. These symptom groups reflect the complex way trauma can affect a person’s memory, thoughts, emotional regulation, and physical state. An individual must meet specific minimum requirements within each of these four areas for a formal diagnosis to be considered.
Intrusion Symptoms
This cluster involves the involuntary re-experiencing of the traumatic event. The most commonly recognized intrusion symptom is the occurrence of recurrent, involuntary, and intrusive distressing memories of the event. These are unwanted thoughts or images that break into the person’s awareness and cause significant distress.
Another form of re-experiencing is recurrent distressing dreams or nightmares related to the traumatic event. Dissociative reactions, known as flashbacks, are also a form of intrusion where the person feels or acts as if the traumatic event is happening again. These reactions can range from brief moments of reliving the event to a complete loss of awareness of current surroundings.
A person may experience intense psychological distress when exposed to internal or external cues that resemble the traumatic event. Marked physiological reactions may also occur in response to these cues, triggering a physical stress response like a racing heart or rapid breathing.
Avoidance Symptoms
Avoidance symptoms reflect a deliberate effort to reduce contact with anything that serves as a reminder of the trauma. This cluster focuses on two distinct types of avoidance behaviors.
The first involves avoiding distressing memories, thoughts, or feelings associated with the traumatic event. This is an internal form of avoidance, where the individual mentally suppresses or tries to push away trauma-related cognitive experiences.
The second type of avoidance is directed at external reminders of the trauma. This includes actively avoiding people, places, conversations, or situations that might arouse distressing memories or feelings. For example, a person who was in a car accident might avoid driving or the intersection where the event occurred.
Negative Alterations in Cognition and Mood
This cluster details negative changes in beliefs and emotional states that developed or worsened after the trauma. These symptoms include:
- Inability to remember an important aspect of the traumatic event, often a form of dissociative amnesia not due to head injury or substance use.
- Persistent and exaggerated negative beliefs or expectations about oneself, others, or the world, such as believing “I am bad” or “The world is completely dangerous”.
- Persistent distorted cognitions about the cause or consequences of the traumatic event, which often leads to blaming oneself or others.
- A persistent negative emotional state, such as continuous feelings of fear, anger, guilt, or shame.
- Markedly diminished interest or participation in previously significant activities.
- Feelings of detachment or estrangement from others, where the individual feels isolated or emotionally distant.
- Persistent inability to experience positive emotions, such as happiness or satisfaction.
Alterations in Arousal and Reactivity
Symptoms in this cluster relate to a heightened, persistent sense of threat and exaggerated responsiveness. The individual is often described as being constantly “on edge.”
- Irritable behavior and angry outbursts, typically expressed as verbal or physical aggression.
- Reckless or self-destructive behavior, such as excessive substance use or dangerous driving.
- Hypervigilance, where the person is constantly scanning the environment for signs of danger.
- Exaggerated startle response to unexpected noises or movements.
- Problems with concentration.
- Sleep disturbance, including trouble falling asleep or staying asleep.
Symptom Duration and Functional Impairment
The presence of these symptoms alone is not sufficient for a diagnosis of Post-Traumatic Stress Disorder. A diagnosis requires that the full set of symptoms, meeting the minimum threshold in each of the four clusters, must persist for more than one month. Symptoms that last less than a month are often classified as acute stress disorder.
Furthermore, the symptoms must cause clinically significant distress or impairment in social, occupational, or other important areas of functioning. This means the persistent difficulties must significantly interfere with the person’s ability to maintain relationships, perform at work, or engage in their usual daily tasks.