Acute Stress Disorder

Updated: Nov 16, 2021
Author: Roy H Lubit, MD, PhD; Chief Editor: David Bienenfeld, MD 

Overview

Practice Essentials

Acute stress disorder (ASD) is an intense and unpleasant reaction that develops in the weeks following a traumatic event. Symptoms typically last for one month or less. If symptoms persist beyond one month, affected individuals are considered to have posttraumatic stress disorder (PTSD).

Signs and symptoms

Most individuals have some symptoms after a significant traumatic event. A minority have sufficient symptoms to fulfill the diagnostic criteria for ASD or posttraumatic stress disorder (PTSD). These symptoms include:

  • Severe persistent problematic symptoms - Marked depression (eg, hopelessness, a feeling of worthlessness, or overwhelming worry), marked hyperarousal (eg, panic attacks, rage, extreme irritability, or intense agitation), extreme numbness, inability to control emotions even when it is important to do so, persistent problems in work or school, and significant problems in self-care

  • Exacerbation or reoccurrence of preexisting psychiatric problems

  • Dissociative symptoms (eg, depersonalization, derealization, fugue, and amnesia)

  • Intrusive reexperiencing - Terrifying memories, persistent nightmares, and flashbacks

  • ASD

  • PTSD (occurs in 10-30% of individuals who are highly exposed to the traumatic event)

  • Substance abuse

  • Aggression

  • In children, aggression, risk taking, or sexual acting out

Diagnosis

The American Psychiatric Association’s Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5), lists 5 specific diagnostic criteria for ASD.[1]

The first criterion is exposure to actual or threatened death, serious injury, or sexual violation in 1 (or more) of the following ways:

  • Directly experiencing the traumatic events(s)

  • Witnessing, in person, the event(s) happening to others

  • Learning that the event(s) occurred to a close family member or close friend (in cases of actual or threatened death of a family member or friend, the event[s] must have been violent or accidental)

  • Experiencing repeated or extreme exposure to aversive details of the traumatic event(s) (eg, first responders collecting human remains or police officers repeatedly exposed to details of child abuse)

The second criterion is the presence of at least 9 of 14 symptoms from any of 5 categories—intrusion, negative mood, dissociation, avoidance, and arousal—beginning or worsening after the traumatic event(s) occurred.

The third DSM-5 diagnostic criterion for ASD is that the duration of the disturbance is 3 days to 1 month after trauma exposure. Although symptoms may begin immediately after a traumatic event, they must last at least 3 days for a diagnosis of ASD to be made.

The fourth criterion is that the disturbance causes clinically significant distress or impairment in social, occupational, or other important areas of functioning.

The fifth and final criterion is that the disturbance cannot be attributed to the physiologic effects of a substance (eg, a medication or alcohol) or another medical condition (eg, mild traumatic brain injury) and cannot be better explained by a diagnosis of brief psychotic disorder.

Management

Treatment for ASD involves general supportive measures, psychological and behavioral interventions, and pharmacologic therapy.

Background

All people experience traumatic events in their lives. All people lose loved ones, 1 in 4 women experience rape or attempted rape during their lifetime, and 1 million children are abused or neglected each year. In 2000, one quarter of a million Americans were raped or sexually assaulted, three quarters of a million were robbed, and half a million were assaulted. Millions of children are bullied in school, 7% of men and 22% of women are assaulted by an intimate partner, and 3 million people a year are involved in car accidents.

Most Americans were shocked by the loss of thousands of lives in the terrorist attack on the World Trade Center. Natural disasters such as Hurricane Katrina and the earthquake in Haiti can unexpectedly take thousands of lives. Victims of such disasters, along with those who love them, are vulnerable to considerable emotional turmoil and a variety of symptoms after a traumatic event and the loss of loved ones.

Typically, emotional responses to disaster develop in the following 4 phases:

  • Impact phase - Individuals often feel stunned during the first few days; in the first week, disbelief, numbness, fear, and possibly confusion to the point of disorganization occur

  • Crisis phase - After the initial impact has been absorbed, individuals can experience a number of feelings; they may alternate between denial and intrusive symptoms with hyperarousal; they may experience somatic symptoms (eg, fatigue, dizziness, headaches, and nausea), as well as anger, irritability, apathy, and social withdrawal; or they may be angry with caregivers who fail to solve problems or who are unable to respond in a fully organized way in the chaos of the crisis

  • Resolution phase - Grief, guilt, and depression are often prominent during the first year as individuals continue to cope with their losses

  • Reconstruction phase - Reappraisal, assignment of meaning, and integration of the event into a new self-concept occur

Only a minority of victims of traumatic events have sufficient symptoms to fulfill the diagnostic criteria for acute stress disorder (ASD) or posttraumatic stress disorder (PTSD).

Diagnostic criteria (DSM-5)

The American Psychiatric Association’s Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5), lists 5 specific diagnostic criteria for ASD.[1]

The first criterion is exposure to actual or threatened death, serious injury, or sexual violation in 1 (or more) of the following ways:

  • Directly experiencing the traumatic events(s)

  • Witnessing, in person, the event(s) happening to others

  • Learning that the event(s) occurred to a close family member or close friend (in cases of actual or threatened death of a family member or friend, the event[s] must have been violent or accidental)

  • Experiencing repeated or extreme exposure to aversive details of the traumatic event(s) (eg, first responders collecting human remains or police officers repeatedly exposed to details of child abuse)

The second criterion is the presence of at least 9 of 14 symptoms from any of 5 categories—intrusion, negative mood, dissociation, avoidance, and arousal—beginning or worsening after the traumatic event(s) occurred.

Intrusion symptoms include the following:

  • Recurrent, involuntary, and intrusive distressing memories of the traumatic event(s); children may engage in repetitive play during which themes or aspects of the traumatic event(s) are expressed

  • Recurrent distressing dreams in which the content or affect of the dream is related to the event(s); children may experience frightening dreams without recognizable content

  • Dissociative reactions (eg, flashbacks) in which the individual feels or acts as if the traumatic event(s) were recurring

  • Intense or prolonged psychological distress or marked physiologic reactions in response to internal or external cues that symbolize or resemble an aspect of the traumatic event(s)

Negative mood consists of the following:

  • Persistent inability to experience positive emotions (eg, inability to experience happiness, satisfaction, or loving feelings)

Dissociative symptoms include the following:

  • Altered sense of the reality of one’s surroundings or oneself (eg, seeing oneself from another’s perspective, being in a daze, or feeling that time is slowing)

  • Inability to remember an important aspect of the traumatic event(s), typically resulting from dissociative amnesia and not from other factors (eg, head injury, alcohol or drugs)

Avoidance symptoms include the following:

  • Efforts to avoid distressing memories, thoughts, or feelings about or closely associated with the traumatic event(s)

  • Efforts to avoid external reminders (eg, people, places, conversations, activities, objects, or situations) that arouse distressing memories, thoughts, or feelings about or closely associated with the traumatic event(s)

Arousal symptoms include the following:

  • Sleep disturbance (eg, difficulty falling or staying asleep or restlessness during sleep)

  • Irritable behavior and angry outbursts (with little or no provocation), typically expressed as verbal or physical aggression toward people or objects

  • Hypervigilance

  • Problems with concentration

  • Exaggerated startle response

The third DSM-5 diagnostic criterion for ASD is that the duration of the disturbance is 3 days to 1 month after trauma exposure. Although symptoms may begin immediately after a traumatic event, they must last at least 3 days for a diagnosis of ASD to be made.

The fourth criterion is that the disturbance causes clinically significant distress or impairment in social, occupational, or other important areas of functioning.

The fifth and final criterion is that the disturbance cannot be attributed to the physiologic effects of a substance (eg, a medication or alcohol) or another medical condition (eg, mild traumatic brain injury) and cannot be better explained by a diagnosis of brief psychotic disorder.

ASD may progress to PTSD after 1 month, but it may also be a transient condition that resolves within 1 month of exposure to traumatic event(s) and does not lead to PTSD.[1] In about 50% of people who eventually develop PTSD, the initial presenting condition was ASD. Symptoms of ASD may worsen over the initial month can occur, often as a consequence of ongoing stressors or additional traumatic events.

Etiology

Factors increasing the risk of acute stress disorder (ASD) and posttraumatic stress disorder (PTSD) in someone suffering a sufficient precipitating event include the following:

  • Loss of a loved one in the event

  • Significant injury from the event

  • Witnessing of horrendous images

  • Dissociation at the time of the traumatic event

  • Development of serious depressive symptoms within 1 week that last for 1 month or longer

  • Numbness, depersonalization, a sense of reliving the trauma, and motor restlessness after the event

  • Preexisting psychiatric problems

  • Previous trauma

  • Loss of home or community

  • Extended exposure to danger

  • Toxic exposure

  • Absent social supports, or social supports who were also traumatized and thus are incapable of adequate emotional availability

Epidemiology

According to the DSM-5,[1] the frequency with which acute stress disorder (ASD) develops in individuals exposed to traumatic events depends on both the nature of the event and the context in which it is assessed. Within and outside the United States, ASD tends to occur at the following rates:

  • 20-50% of cases follow interpersonal traumatic events (eg, assault, rape, and witnessing a mass shooting)

  • 13-21% of motor vehicle accidents

  • 14% of mild traumatic brain injuries

  • 19% of assaults

  • 10% of severe burns

  • 6-12% of industrial accidents

Patient Education

The following are useful websites for patient and family education:

  • Duke University Health Services, Bereavement, Coping After a Traumatic Death

  • The University of Iowa, Coping with Death, Grief, and Loss

  • Helpguide.org, Coping with Grief and Loss: Guide to Grieving and Bereavement

For other patient education resources, see the Mental Health Center, as well as Grief and Bereavement and Posttraumatic Stress Disorder (PTSD).

 

Presentation

History

Traumatic events can lead to a wide variety of emotional reactions. The treating clinician must understand that underneath the individual’s reaction is an attempt to cope with the traumatic event. Most individuals have some symptoms after a significant traumatic event. A minority have sufficient symptoms to fulfill the diagnostic criteria for acute stress disorder (ASD) or posttraumatic stress disorder (PTSD).

The following symptoms are relatively common after traumatic events:

  • Emotional reactions - Shock, daze, grief, anxiety, guilt, anger, numbness, helplessness, shame, and emptiness; decreased ability to feel pleasure, interest, or love; children may regress

  • Cognitive reactions - Nightmares, poor concentration, unwanted memories of the disaster, self-blame, confusion, disorientation, indecisiveness, and worry

  • Physical reactions - Difficulty sleeping, exaggerated startle response, tension, fatigue, irritability, aches and pains, tachycardia, nausea, and changes in appetite or libido

  • Interpersonal reactions - Distrust, conflict, withdrawal, work problems, school problems, irritability, decreased intimacy, domineering demeanor, and a feeling of being rejected or abandoned; children may become clingy or oppositional

More significant symptoms that call for professional consultation include the following:

  • Severe persistent problematic symptoms - Marked depression (eg, hopelessness, a feeling of worthlessness, or overwhelming worry), marked hyperarousal (eg, panic attacks, rage, extreme irritability, or intense agitation), extreme numbness, inability to control emotions even when it is important to do so, persistent problems in work or school, and significant problems in self-care

  • Exacerbation or reoccurrence of preexisting psychiatric problems

  • Dissociative symptoms (eg, depersonalization, derealization, fugue, and amnesia)

  • Intrusive reexperiencing - Terrifying memories, persistent nightmares, and flashbacks

  • ASD

  • PTSD (occurs in 10-30% of individuals who are highly exposed to the traumatic event)

  • Substance abuse

  • Aggression

  • In children, aggression, risk taking, or sexual acting out

The following are signs that the patient needs help:

  • Task-oriented activities are not being performed

  • Task-oriented activity is not goal-directed, organized, or effective

  • The survivor is overwhelmed by emotion most of the time

  • Emotions cannot be modulated when necessary

  • The survivor inappropriately blames himself or herself, and the self-blame generalizes to the entire self

  • The survivor is isolated and avoids the company of others

  • The survivor contemplates or plans suicide or homicide

Traumatic grief

Traumatic grief is an example of a complicated grief reaction that occurs after the traumatic death of someone close. It may occur when the death results from war, disasters, accidents, suicide, or homicide. In traumatic bereavement, the individual is preoccupied with images of the traumatic event, rather than of the person who is deceased, as is typical in normal bereavement. Moreover, the individual has difficulty passing through the mourning process and moving on with his or her life.

A person experiencing traumatic grief needs treatment for both trauma and grief. He or she also needs help in remembering an intact representation of the deceased person rather than being filled with images of the person being killed. If no body is present after the death, placing a picture of the individual in nondegradable plastic in the coffin can be helpful.

Physical Examination

The patient’s mental status must be assessed. Common findings in patients with acute stress disorder (ASD) are as follows:

  • Appearance - Individuals may be disheveled and unclean and show the effects of dehydration and failure to care for themselves

  • Affect and mood - Patients may appear sad, anxious, irritable, emotionally labile, apathetic, angry, or calm; depressive illness occurs in 17-27% of survivors during the first year after a death

  • Thought content - Individuals may feel helpless, be in a state of disbelief, be confused, have markedly impaired concentration, have lowered self-esteem, or be driven to search for the deceased

  • Perceptions - Patients may have hallucinations (visual or auditory) that the deceased person is present; flashbacks, feelings of unreality, numbness, and denial may occur

  • Judgment and insight - Confusion in combination with preoccupation with those they have lost may impair individuals’ judgment and insight

  • Suicidal or homicidal ideation - Suicidal thoughts occur in as many as 54% of survivors and may continue up to 6 months after the death; thoughts or plans of homicide may arise

Physical complaints arising from grief may include the following:

  • Loss of appetite

  • Changes in weight

  • Trouble going to sleep or staying asleep

  • Fatigue

  • Chest pain

  • Headache

  • Palpitations

  • Hair loss

  • Gastrointestinal distress

 

DDx

 

Treatment

Approach Considerations

Basic principles of intervention after emotional trauma include the following:

  • Reduce stress 

  • Ensure that survivors have a safe environment

  • Promote contact with loved ones and other sources of support (eg, religious organizations)

  • Support self-esteem; help patients understand that their reaction to the trauma is a normal reaction to an abnormal situation, not a sign of weakness or psychopathology

  • Reassure and help survivors concerning immediate needs, such as rest, food, shelter, social supports, or a sense of belonging to a community (some feel cut off and detached)

  • Promote coping mechanisms

  • Help patients reframe any destructive cognitions (eg, beliefs that they acted terribly and are terrible people or are weak for being so distraught, that life is hopeless or worthless, or that the world is totally unsafe)

  • Administer medication (eg, beta-blockers, alpha-agonists, or nonactivating selective serotonin reuptake inhibitors [SSRIs]), Benzodiazepines have not been shown to be effective, although they are often given.  They are particularly risky in the elderly, individuals with subsance abuse problems and traumatic brain injury.

  • Avoid increasing stress - Avoid prompting discussion of issues that cannot be resolved; avoid abreaction in groups and the resulting contagion effect; respect defenses, and do not force reality on people who cannot handle it yet; keep in mind that debriefing may be harmful

  • Discuss the experience with patients who want to talk about it, and avoid pressuring those who do not wish to discuss it

  • Identify persons at high risk - Screen for physical causes of psychiatric problems (eg, dehydration, head trauma, infection, metabolic abnormality, or toxins)

  • Have faith in the normal healing processes

General Supportive Measures

It is essential for caregivers to remain available and not to allow a grieving person to become isolated. The following are helpful for adults who are grieving:

  • Take action (eg, call, send a card, give hugs, or help with practical matters)

  • Be available after others get back to their own lives

  • Be a good listener, but do not give advice

  • Do not be afraid to talk about the loss

  • Talk about the person who died by name

  • Do not minimize the loss; avoid clichés and easy answers

  • Be patient with the bereaved; there are no shortcuts

  • Encourage bereaved individuals to care for themselves

  • Remember significant days and memories

  • Do not try to distract the bereaved from grief through forced cheerfulness

When dealing with children who are grieving or traumatized, it is particularly important to offer reassurance regarding their own safety and the safety of their loved ones (insofar as is possible). It should be emphasized to these children that such devastating events are very rare, that people are there to take care of them, and that they will always be loved. The following are helpful for grieving or traumatized children:

  • Be emotionally available to children despite personal loss (or fears)

  • Give children more time than usual

  • Encourage them to share their feelings, to talk at weekly family meetings, and to use drawings and puppets to express their feelings

  • Let them know it is all right to talk about unpleasant feelings (including sadness and anger) and listen to them; sharing personal feelings of sadness with them is all right as well

  • Check to see if children feel that they somehow caused the death or disaster or if they have other misunderstandings, and take pains to reassure them or correct any misunderstanding; do not assume children are fine just because they are not saying anything

  • Understand that children probably know more than you think they do; make sure to ask what the child knows and what questions he or she has

  • Monitor and limit television watching after a disaster, lest this flood them or desensitize them to violence; when they do watch, watch it with them and discuss the events

  • In discussing traumatic events with children, share only the details they can deal with; be honest, but do not overload them with facts

  • Encourage action, such as sending letters to victims, to keep them from feeling helpless

  • Understand that regression, fear, sleep problems, and anger toward remaining family members are common after a loss or trauma

  • Do not force children to go to the funeral if they do not want to, but help them create a ritual

  • Maintain as normal a schedule as possible

  • Encourage patients to eat balanced meals on time and drink fluids; to get enough sleep, relaxation, and exercise; and to avoid alcohol and caffeine

If serious signs appear and last more than a couple of weeks, help should be sought. Signs that help is needed include the following:

  • Extended depression and loss of interest in activities and events

  • Inability to sleep, loss of appetite, or prolonged fear of being alone

  • Extended period of marked regression

  • Excessive imitation of the deceased or repeated statements about wanting to join the deceased

  • Withdrawal from friends

  • Serious drop in school performance or refusal to go to school

  • Persistent fears

  • Persistent irritability and being easily startled

  • Behavior problems

  • Physical complaints

Rescue workers may develop the same symptoms as victims, including those of acute stress disorder (ASD) or posttraumatic stress disorder (PTSD). As many as 1 in 3 rescue workers develop PTSD. Measures for helping rescue workers deal with stress after traumatic events include the following:

  • Encourage staying in touch with family and friends

  • Be sure that rescue workers get rest, food, exercise, and relaxation

  • Encourage understanding of survival guilt

  • Explain how chaos and confusion inevitably lead to upset between individuals and groups that are participating in the rescue effort

  • Develop a buddy system, and encourage support of coworkers

  • Encourage workers to defuse after troubling incidents and after each shift

  • After the rescue operation, encourage workers to take a few days to decompress and attend a debriefing

  • Do not overwhelm children with talk of experiences as a rescue worker; ask about their activities

Psychological and Behavioral Interventions

Debriefing

Critical incident stress debriefing is one of the most commonly considered interventions after a traumatic event.[2, 3, 4, 5, 6] Classically, critical incident stress debriefing is carried out in 7 stages, as follows:

  • Introduction (purpose of the session)

  • Description of the traumatic event

  • Appraisal of the event

  • Exploration of the participants’ emotional reactions during and after the event

  • Discussion of the normal nature of symptoms after traumatic events

  • Discussion of ways of dealing with further consequences of the event

  • Discussion of the session and formulation of practical conclusions

It should be kept in mind that research efforts have not shown critical stress debriefing to be effective in preventing PTSD, depression, or anxiety. In some cases, if performed poorly, debriefing can even harm survivors by increasing arousal and overwhelming their defenses. Operational debriefing, which focuses on normalizing emotional response, informing patients of services available to them, and providing general support, is safer.

In engaging in a 1- to 2-session intervention after a traumatic event, there are several guidelines that should be followed to help avoid harm and maximize the chance of benefit, as follows:

  • Provide trained individuals to perform the intervention

  • Avoid ventilating feelings at high levels; this can lead to contagion and flooding rather than calming and improved ability to cope with feelings

  • Do not pressure individuals to talk about things they do not want to talk about; respect their defenses, including denial

Critical tasks to cover include the following:

  • Psychoeducation to help patients see that the feelings they are having are not a sign of weakness or mental illness but a normal reaction to a very disturbing situation

  • Discussion of ways to improve coping skills, including getting adequate rest, recreation, food, and fluids

  • Avoidance of excessive exposure to media coverage of the traumatic incident

  • Discussion of common cognitive distortions, such as survivor guilt and fears that the world is totally unsafe

  • Explanation of the signs and symptoms indicating that the survivor should get professional help

Cognitive-behavioral therapy

Whereas 70% of those receiving supportive therapy or no therapy after a traumatic event develop PTSD, only about 10-20% of those who receive cognitive-behavioral therapy (CBT) shortly after such an event develop PTSD.[7, 8, 9, 10, 11, 12] Moreover, patients who receive CBT with or without hypnosis report less reexperiencing and fewer avoidance symptoms than patients who receive supportive counseling. Individuals are aided by the following:

  • Seeing that people are concerned about them

  • Learning about the range of normal responses to trauma and hearing that their emotional reactions are normal responses to an abnormal event (rather than a sign of weakness or pathology)

  • Being reminded to take care of concrete needs (eg, food, fluids, and rest)

  • Cognitive restructuring (changing destructive schema to more constructive ones [see the Table below])

  • Learning relaxation techniques

  • Undergoing exposure to avoided situations either via guided imagery and imagination or in vivo

  • Desensitization to painful memories via repeated controlled exposures and systematic desensitization

Table. Cognitive Interventions: Changing Malignant Schemata to Constructive Schemata (Open Table in a new window)

Malignant Schemata

Constructive Schemata

Life has no meaning

Right now it is hard to make sense of what happened

I can’t go on

What happened is very painful; dealing with it is hard but will get easier over time

I behaved terribly

I was frightened and unsure what to do and made some bad choices

The world is unsafe

Disasters are rare, and many things can be done to protect my safety

I’m losing my mind

Feeling confused and overwhelmed after a traumatic experience is common

It was my fault it happened

What was done to me was a crime

Current data suggest that if the resources are available, a course of CBT should be offered to those at high risk for developing PTSD. CBT should be performed by someone trained in the technique. Severe, relatively common destructive cognitions may arise after a traumatic event and may have to be addressed.

Brief school intervention

A brief school intervention lasts 1-2 hours and uses 4 therapists per class. A teacher is present, and parents are informed. The intervention includes the following steps:

  • Introduce the therapists, and ask students to guess why they have come to the classroom

  • Explain that therapists have come to talk about the disaster, and encourage students to share what they know for 10-30 minutes; validate correct information, and be calm

  • Have children draw while therapists circulate, and ask students to tell them about their drawings

  • Reassure students that their symptoms are normal and will ease; that people have different symptoms; that disasters are rare; and that teachers, parents, and counselors are available to help them

  • Having students do a second drawing in which they depict a future and a positive state of the world is very important; the first picture is likely to focus on the trauma, their loss, and its effect on them; ideally, the second picture should show healing and restoration of normal life

  • Thank the students and the teachers, and redirect their attention to learning.

Pharmacologic Therapy

The use of medications to decrease arousal and insomnia may have a long-term impact.

Beta blockers (as well as alpha-adrenergic agents) may limit hyperarousal both initially and over the longer term.[13] For extreme agitation, aggression, psychosis, or dissociation, an atypical neuroleptic or mood stabilizer may be needed.

Diphenhydramine and other medications may be helpful for improving sleep. Benzodiazepines, by limiting hyperarousal and fostering sleep, can be helpful in the initial stages; however, continuous administration may interfere with grieving and readaptation, because these agents can interfere with learning.[14] Longer-acting agents are particularly beneficial when medication is administered at the emergency site and follow-up treatment is in short supply.

SSRIs can be helpful in dealing with the core symptoms (including anxiety, depression, withdrawal, and avoidance) and can play a central role in longer-term treatment.

Comorbid conditions such as attention deficit hyperactivity disorder (ADHD) should be targeted. Reduction in even 1 disabling symptom (eg, insomnia or hyperarousal) may have a powerful positive impact on the individual’s ability to re-compensate.

 

Medication

Medication Summary

Current research indicates that SSRIs prazosin and propranolol may be helpful in the treatment of posttraumatic stress disorder (PTSD).  Benzodiazepines are often used but present significant risks especially to the elderly, individuals with co-morbid substance abuse histories, and traumatic brain injury.

 

Beta-Adrenergic Blocking Agents

Class Summary

Beta blockers inhibit chronotropic, inotropic, and vasodilatory responses to beta-adrenergic stimulation.

Propranolol (Inderal LA, InnoPran XL, Hemangeol)

Propranolol may be useful for the treatment of hyperarousal.

Selective Serotonin Reuptake Inhibitors

Class Summary

SSRIs are first-line agents for managing anxiety, depression, avoidance behavior, and intrusive recollections. They are antidepressant agents that are chemically unrelated to tricyclic, tetracyclic, or other available antidepressants. SSRIs inhibit central nervous system (CNS) neuronal uptake of serotonin (5HT). They may also have a weak effect on norepinephrine and dopamine neuronal reuptake.

Citalopram (Celexa)

Citalopram enhances serotonin activity through selective reuptake inhibition at the neuronal membrane. It is the least activating of the SSRIs and is particularly useful in ASD. The incidence of adverse effects (especially sexual) is less than with other SSRIs.

Escitalopram (Lexapro)

Escitalopram is the S-enantiomer of citalopram. It may have a faster onset of depression relief (1-2 weeks) in comparison with other antidepressants.

Sertraline (Zoloft)

Sertraline selectively inhibits presynaptic serotonin reuptake with minimal or no effect on the reuptake of norepinephrine or dopamine.

Benzodiazepines

Class Summary

Benzodiazepines bind to a specific receptor on the gamma amino-butyric acid (GABA) receptor complex, thereby increasing the affinity of GABA for its receptor. They also increase the frequency of chlorine channel opening in response to GABA binding. GABA receptors are chlorine channels that mediate postsynaptic inhibition, resulting in postsynaptic neuron hyperpolarization. The final result is a sedative-hypnotic and anxiolytic effect.

Alpha-Adrenergic Agonists

Class Summary

The centrally acting alpha2 -adrenergic agonists clonidine and guanfacine have been used to treat children with attention deficit hyperactivity disorder (ADHD). Inhibition of norepinephrine release in the brain may be its mechanism of action.

Antihistamines, Sedating

Class Summary

Older, sedating antihistamines (eg, diphenhydramine) are often prescribed as sedatives because of their CNS-depressing properties.