Acute Stress Disorder: Symptoms, Causes and How to Cope

Written by the Lyte Psychiatry clinical team. Clinically reviewed by Ana G., LPC, and medically reviewed by Dr. Akinwande Akintola, MD, supervising physician. Last reviewed: November 4, 2026.

Acute stress disorder is a trauma reaction with symptoms such as flashbacks, nightmares, numbness and being on edge that occur between three days and one month after a frightening event. The American Psychiatric Association notes its symptoms are similar to PTSD, and that about half of people with it go on to have PTSD. Early support, routines and trauma-focused therapy can shorten the course.

This article is for adults who have recently lived through or witnessed something traumatic, such as a crash, an assault, a sudden death or a disaster, and for the people around them. It explains the symptoms, how clinicians separate this from PTSD, a week-by-week coping plan and when to get help sooner in Texas.

What is acute stress disorder?

It is a diagnosable condition that can follow a traumatic event, defined by intense stress symptoms in the first month. The American Psychiatric Association (APA) states that "acute stress disorder may occur after a traumatic event, just as PTSD does, and the symptoms are similar," but "the symptoms occur between three days and one month after the event."

The APA adds that people with the condition "may relive the trauma, have flashbacks or nightmares and may feel numb or detached from themselves." Those dissociative feelings, as if watching yourself from outside or as if the world is unreal, are a recognized part of the picture and are frightening in their own right.

How is acute stress disorder different from PTSD?

The main difference is timing: the acute condition is diagnosed in the first month, while PTSD requires symptoms that persist beyond it. The APA states that "for a person to be diagnosed with PTSD, symptoms must last for more than a month" and must cause significant distress or problems in daily functioning. The National Center for PTSD similarly advises seeing a provider if symptoms last longer than a month, are very upsetting or disrupt daily life.

The APA also notes that "about half of people with acute stress disorder go on to have PTSD." The other half improve, which is worth holding on to in the hardest week. That figure is why the first month is treated as a window: what happens in those weeks, including sleep, support and early therapy, may shape what comes after.

What are the symptoms?

Symptoms cluster into intrusion, avoidance, negative mood, dissociation and arousal. The National Institute of Mental Health (NIMH) lists common reactions after trauma that include trouble sleeping, feeling anxious or on edge, and difficulty concentrating. In the disorder these are stronger and more persistent. Typical signs:

• Intrusion: unwanted memories, flashbacks, nightmares, intense distress at reminders.
• Avoidance: steering clear of places, people, conversations or thoughts connected to the event.
• Negative mood: inability to feel positive emotions, guilt, shame or hopelessness.
• Dissociation: feeling numb, detached, in a daze, or unable to remember parts of the event.
• Arousal: poor sleep, irritability, jumpiness, hypervigilance, trouble concentrating.

Physical symptoms are common too. The National Center for PTSD describes physical and emotional reactions after trauma and notes that stress reactions do not automatically mean PTSD and that most people recover on their own.

What causes it?

It is caused by exposure to a traumatic event, meaning actual or threatened death, serious injury or sexual violence, experienced directly, witnessed, or learned about happening to someone close. Examples include vehicle crashes, assaults, severe storms and floods, workplace accidents, medical emergencies and sudden bereavement.

Why one person develops it and another does not is not fully understood. NIMH lists factors that make needing more help more likely after trauma, including prior trauma, lack of support and ongoing stress. None of these is a personal failing; they are risk factors clinicians use to decide who to check on sooner.

How do I cope in the first month, week by week?

Cope by protecting the basics first, then adding gentle exposure to ordinary life, then getting professional help if symptoms are not easing. NIMH's guidance for coping with traumatic events includes avoiding alcohol and drugs, keeping regular meals and sleep, and spending time with supportive people. A labelled example plan:

1. Days 1–3: safety and basics. Treat injuries, eat, drink water, sleep when you can. Tell one trusted person what happened. Do not make big decisions.
2. Days 4–7: routines. Return to simple daily structure, such as regular wake time, meals and a short walk. Limit news or social media replays of the event.
3. Week 2: gentle re-entry. Resume one avoided but safe activity, such as driving a short familiar route with a passenger. Keep a brief note of sleep and symptoms.
4. Week 3: check progress. If nightmares, flashbacks or numbness are the same or worse, book an evaluation now rather than waiting for the one-month mark.
5. Week 4 and beyond: professional support. If symptoms persist past a month, PTSD becomes the question, and trauma-focused therapy is the standard next step.

Why do the first weeks matter so much?

The first weeks matter because the brain is still deciding how to file the event, and sleep, support and avoidance all influence that process. Avoiding every reminder brings short-term relief but tends to keep fear alive, while gradual, safe re-exposure lets the alarm settle. That is why clinicians encourage routines and small steps rather than complete withdrawal, and why isolation is a risk factor NIMH highlights.

What treatment is available?

Treatment is mainly psychotherapy, with medication as an option for some people. The APA states that for this condition, "psychotherapy, including cognitive behavior therapy can help control symptoms," and that "medication, such as SSRI antidepressants can also help ease the symptoms." Any medication decision is made with a prescriber; this article is general information, not a recommendation.

Trauma-focused therapies used for PTSD, such as cognitive processing therapy, are often adapted for early intervention. The National Center for PTSD describes cognitive processing therapy as usually 12 weekly sessions with worksheets between sessions. Lyte Psychiatry offers therapy, psychiatric evaluation and medication management in Texas, and can coordinate therapy and medication in one plan.

What should I say when I ask for help?

Say what happened in one sentence, when, and what has changed since; you do not need to describe details you are not ready to share. A checklist for the first call or visit:

• "On [date], I was in / witnessed [brief description]. Since then I have had [nightmares, flashbacks, numbness]."
• "My sleep is [hours]; I am avoiding [places or activities]."
• "I feel detached or unreal at times" if that is true; clinicians need to know.
• "I am / am not drinking or using anything more than usual."
• "I have / do not have thoughts of hurting myself."
• "I would like to know whether this is an acute stress reaction and what treatment you suggest."

Family members can help by listening without pressing for details, offering specific practical help, and checking in again weeks later. See what to say in your first therapy session.

When should you get help sooner?

Get help sooner when safety is at risk, when dissociation is severe, or when you cannot function at all. NIMH lists suicide warning signs that include feeling hopeless or trapped, withdrawing and increased substance use. Red flags in the first month:

• Thoughts of suicide or self-harm, or feeling you would be better off dead.
• Losing time, being unable to tell what is real, or being unable to care for yourself or children.
• Not sleeping for several nights in a row.
• Drinking or using drugs to get through the day or night.
• Untreated injuries, or physical symptoms such as chest pain.

Lyte Psychiatry is an outpatient practice. It does not provide inpatient care, crisis or after-hours coverage, medically supervised detox, or intensive outpatient or partial hospitalization programs. In an emergency use 988 or 911, and see what to do in a mental health crisis right now.

What should Texans know?

Texas sees hurricanes, floods, tornadoes and extreme heat, and disaster-related distress has its own support lines. The Substance Abuse and Mental Health Services Administration (SAMHSA) runs the Disaster Distress Helpline at 1-800-985-5990, available 24/7 by call or text for U.S. residents with disaster-related distress. Texas Health and Human Services also lists 24/7 crisis lines by county (read October 2026).

For ongoing care, Lyte Psychiatry offers telehealth visits to patients who are physically located in Texas at the time of the visit, and all Lyte Psychiatry services are available in Spanish. Veterans and first responders can read mental health care for first responders in DFW.

Getting support in Texas

If it has been a few days since something frightening happened and you are not settling, you do not have to wait a month to ask for help. Most new patients at Lyte Psychiatry are seen within 1–2 business days; weekend appointments are limited. In-person visits are available at the clinic in Pantego, in the Dallas–Fort Worth area. Availability, insurance and clinician fit require confirmation. Learn about PTSD and trauma care or contact the practice.

If you are in a mental-health crisis in the United States, call or text 988. Call 911 for immediate danger.

Educational information, not a diagnosis or individual treatment plan.