Acute stress reaction

Acute stress reaction (ASR), also known as psychological shock, mental shock, or simply shock, is a psychological response to a terrifying, traumatic, or surprising experience. It is an immediate reaction that occurs within minutes to hours of the event and can last from a few days to several weeks. In some cases, ASR may develop into acute stress disorder (ASD), which shares similar symptoms but lasts longer and has specific diagnostic criteria. If left untreated, ASD can progress into post-traumatic stress disorder (PTSD).

Etiology

Acute stress reaction occurs when an individual experiences an intense psychological or emotional response to a traumatic event. Common causes include:

• Natural disasters (e.g., earthquakes, floods, hurricanes)
• Serious accidents (e.g., car crashes, workplace injuries)
• Physical assault, sexual assault, or domestic violence
• Terrorism, war trauma, or mass violence
• Sudden death of a loved one
• Life-threatening medical diagnoses (e.g., myocardial infarction, stroke)

Pathophysiology

Acute stress reaction is mediated by the sympathetic nervous system and the hypothalamic-pituitary-adrenal (HPA) axis. The response involves:

• Release of stress hormones – Increased secretion of cortisol, epinephrine, and norepinephrine leads to a "fight-or-flight" response.
• Heightened arousal – Increased heart rate, blood pressure, and respiration rate to prepare the body for immediate action.
• Cognitive impairment – Difficulty in processing emotions and memories, which may contribute to dissociation and intrusive thoughts.

Clinical Presentation

Symptoms of acute stress reaction typically develop within hours of a traumatic event and can persist for days to weeks. The symptoms can be categorized into four clusters:

1. Intrusive Symptoms

• Recurrent, involuntary, and distressing memories of the traumatic event.
• Flashbacks in which the person feels as though the event is recurring.
• Nightmares or distressing dreams related to the trauma.
• Intense psychological or physiological distress when exposed to trauma-related cues.

2. Dissociative Symptoms

• A sense of detachment from oneself (depersonalization) or surroundings (derealization).
• Emotional numbness or reduced responsiveness to external stimuli.
• Temporary amnesia or difficulty recalling details of the trauma.

3. Avoidance Symptoms

• Avoidance of places, people, or conversations that remind the individual of the trauma.
• Efforts to suppress thoughts or feelings associated with the traumatic event.

4. Hyperarousal Symptoms

• Increased irritability, anger outbursts, or aggression.
• Hypervigilance and an exaggerated startle response.
• Insomnia and difficulty maintaining sleep.
• Difficulty concentrating or focusing.

Diagnostic Criteria

According to the International Classification of Diseases (ICD-11) and the Diagnostic and Statistical Manual of Mental Disorders (DSM-5), acute stress reaction is differentiated from acute stress disorder based on symptom duration and severity.

Acute Stress Reaction (ICD-11)

• Occurs immediately after exposure to trauma.
• Symptoms typically resolve within days to a few weeks.
• Symptoms interfere with normal functioning but do not meet the full criteria for PTSD.

Acute Stress Disorder (DSM-5)

• Symptoms last between 3 days to 1 month.
• Requires the presence of at least 9 symptoms across the four symptom clusters.
• Causes significant impairment in social, occupational, or other areas of functioning.

Differential Diagnosis

Acute stress reaction and acute stress disorder must be distinguished from:

• Post-traumatic stress disorder (symptoms lasting longer than a month)
• Generalized anxiety disorder (chronic worry not linked to a specific event)
• Panic disorder (sudden episodes of fear with no identifiable trauma)
• Adjustment disorder (emotional distress in response to stress, but without traumatic exposure)

Treatment

The management of acute stress reaction and acute stress disorder focuses on immediate psychological support, symptom relief, and long-term stabilization.

Psychological Interventions

• Psychological first aid – Providing immediate emotional support, ensuring safety, and normalizing reactions.
• Cognitive-behavioral therapy (CBT) – Trauma-focused CBT (TF-CBT) is effective in preventing PTSD.
• Exposure therapy – Gradual exposure to trauma-related memories to reduce avoidance behavior.
• Eye movement desensitization and reprocessing (EMDR) – A structured therapy that helps process traumatic memories.

Pharmacological Management

• Selective serotonin reuptake inhibitors (SSRIs) – Used to reduce anxiety and depressive symptoms.
• Benzodiazepines – May be used short-term for severe anxiety or insomnia but carry a risk of dependence.
• Beta-blockers (e.g., propranolol) – Can reduce hyperarousal symptoms such as increased heart rate and tremors.
• Prazosin – May be used to alleviate nightmares and sleep disturbances.

Prognosis

Most individuals recover from acute stress reaction within weeks without long-term consequences. However, if symptoms persist beyond one month, the risk of developing post-traumatic stress disorder (PTSD) increases. Early intervention and psychological support can improve outcomes.

Prevention

• Early trauma debriefing – While controversial, structured discussions may help reduce distress.
• Social support – Encouraging connections with family and community.
• Mindfulness and stress reduction techniques – Meditation, deep breathing, and relaxation training.

Related Conditions

• Post-traumatic stress disorder (PTSD)
• Generalized anxiety disorder
• Panic disorder
• Adjustment disorder
• Dissociative disorders

See Also

• Coping mechanisms
• Trauma-informed care
• Neurobiology of stress