Symptoms usually start within 3 months of an event, but they can begin later. For a person to receive a diagnosis of PTSD, they must meet criteria that are set out by the American Psychological Association’s (APA) Diagnostic and Statistical Manual Fifth Edition (DSM-5). According to these guidelines, the person must:

1. Have been exposed to death or threatened death, serious injury or sexual violence whether directly, through witnessing it, by it happening to a loved one, or during professional duties
2. Experience the following for more than one month:
   • one or more intrusion symptoms
   • one or more avoidance symptoms
   • two or more symptoms that affect mood and thinking
   • two or more arousal and reactivity symptoms that began after the trauma

Here are some examples of these four types of symptom: Intrusion symptoms:

• nightmares
• flashbacks and a sensation that the event is happening again
• fearful thoughts

Avoidance symptoms:

• refusing to discuss the event
• avoiding situations that remind the person of the event

Arousal and reactivity symptoms:

• difficulty sleeping
• irritability and angry outbursts
• hypersensitivity to possible dangers
• feeling tense and anxious

Symptoms that affect mood and thinking:

• inability to remember some aspects of the event
• feelings of guilt and blame
• feeling detached and estranged from others and emotionally and mentally numbed
• having a reduced interest in life
• difficulty concentrating
• mental health problems, such as depression, phobias, and anxiety

In addition, the symptoms must lead to distress or difficulty coping with work or relationships, and they must not be due to the use of medication or other substances, or another health condition.

Physical symptoms

There may also be physical symptoms, but these are not included in the DSM-5 criteria:

• physical effects include sweating, shaking, headaches, dizziness, stomach problems, aches and pains, and chest pain
• a weakened immune system can lead to more frequent infections
• sleep disturbances can result in tiredness and other problems

There may be long-term behavioral changes that contribute to problems and work and a breakdown in relationships. The person may start to consume more alcohol than previously, or to misuse drugs or medications.

Children and teens

In those aged 6 years or under, symptoms may include:

• bedwetting after learning to use the bathroom
• inability to speak
• acting out the event in play
• being clingy with an adult

Between the ages of 5 and 12 years, the child may not have flashbacks and they may not have difficulty remembering parts of the event. However, they may remember it in a different order, or feel that there was a sign that it was going to happen. They may also act out the trauma or express it through play, pictures, and stories. They may have nightmares and be irritable. They may find it hard to go to school or spend time with friends or studying. From the age of 8 years and above, children generally tend to display similar reactions to adults. Between the ages of 12 and 18 years, the person may show disruptive or disrespectful, impulsive or aggressive behavior. They may feel guilty for not acting differently during the event, or they may consider revenge. Children who have experienced sexual abuse are more likely to:

• feel fear, sadness, anxiety, and isolation
• have a low sense of self-worth
• behave in an aggressive manner
• display unusual sexual behavior
• hurt themselves
• misuse drugs or alcohol

Screening

As part of the diagnostic process, the person may be given a screening test to assess whether or not they have PTSD. The time taken for this can range from 15 minutes to several one-hour sessions. A longer assessment may be used if there are legal implications or if a disability claim depends on it. If symptoms disappear after a few weeks, there may be a diagnosis of acute stress disorder. PTSD tends to last for longer and the symptoms are more severe and may not appear until some time after the event. Many people recover within 6 months, but some continue to experience symptoms for several years.

PTSD can develop after a traumatic event. Examples include:

• military confrontation
• natural disasters
• serious accidents
• terrorist attacks
• loss of a loved one, whether or not this involved violence
• rape or other types of abuse
• personal assault
• being a victim of crime
• receiving a life-threatening diagnosis

Any situation that triggers fear, shock, horror, or helplessness can lead to PTSD.