How to Tell If Your Character Has Post-Traumatic Stress Disorder

Post-Traumatic Stress Disorder doesn’t just apply to combatants. Understand how it’s diagnosed and what that means before including it in your story.

Characters’ lives aren’t easy. We writers put them through trials, tribulations and traumas, and sometimes those traumas have lasting effects.

Experiencing a traumatic event can have several repercussions for your characters. A strong sense of fear or anger or sadness, intrusive memories of the event, even nightmares about it—all are possible. Just because your character has undergone a trauma and is experiencing some of the after-effects of that, however, doesn’t mean they have Post-Traumatic Stress Disorder (shortened to PTSD).

Think one of your characters might have PTSD or know one’s going to develop it? First things first, make sure you know what PTSD is, understand what’s necessary to be diagnosed with it, and dispel any misconceptions you might have about it. Then you’ll be one step closer to writing about Post-Traumatic Stress Disorder in a way that’s realistic, sensitive and compelling.

To Keep in Mind:

The information in this post comes from the DSM-5 (see ‘Further Reading’). Please do not use it to diagnose yourself or others. It isn’t intended to be a substitute for professional advice so do consult a qualified clinical professional if you have any questions about the diagnosis criteria. Feel free to use this information to diagnose your characters, however!

What Is Post-Traumatic Stress Disorder?

PTSD is a trauma- and stressor-related disorder caused by a very distressing, frightening or stressful event. Contrary to popular belief, it’s not just military combatants who suffer from PTSD. If you were involved in a serious accident, witnessed violent deaths, were a victim of sexual assault, or experienced a natural disaster or terrorist attack, for example, you could also develop Post-Traumatic Stress Disorder.

PTSD can develop immediately after the traumatising event(s), though not necessarily so—sometimes it can take weeks, months or even years before symptoms begin to meet the criteria for diagnosis. In other words, though an individual may be diagnosed with PTSD some time after experiencing trauma, symptoms may begin appearing long before that.

So what actually happens if your character develops PTSD? What are the symptoms and how might they affect their life? Let’s take a look at how PTSD is identified in a clinical setting.

How is Post-Traumatic Stress Disorder Diagnosed?

The presence of one symptom isn’t enough to diagnose PTSD. Rather, several specific criteria need to be met for your character to be classified as having this disorder. We’ll explore what those criteria are in this post and dig into what they actually mean in the next.

Please note: The following criteria only apply to people over the age of six. Children of six years or younger should be diagnosed using a different set of criteria. Also, for the sake of simplicity and easy reading, I’ll be referring to the trauma as an ‘event’ (singular) throughout this post, but please be aware that the original trauma could have occurred several times or across several events, not just the one.

Criterion A:


To be diagnosed with PTSD, your character must have been exposed to actual or threatened death, serious injury or sexual violence in one or more of these ways:

  • Experiencing the traumatic event directly.
  • Witnessing the event as it happened to other people.
  • Learning that a close family member or friend was the victim of the traumatic event. In the case of a family member or friend’s actual or threatened death, the event must have been violent or accidental.
  • Repeated or extreme exposure to traumatising details of the event (for example, first responders collecting human remains or police officers being repeatedly exposed to the details of child abuse). This criterion doesn’t apply to exposure through electronic media, television, films or pictures, unless the exposure is work related, though.

Criterion B:

Intrusion Symptoms

Following the traumatic event, your character must experience one or more of the following symptoms related to the trauma:

  • Recurring, involuntary and intrusive memories of the event, which they find distressing. (Note: In children older than six, themes or aspects of the traumatic event may be expressed during repetitive play.)
  • Recurring distressing dreams, which are related to the traumatic event in content or emotional tone. (Note: Children older than six may have frightening dreams without recognisable content.)
  • Dissociative reactions (i.e., feeling disconnected from yourself or your surroundings, for example, during a flashback), during which your character feels or acts as though the traumatic event is happening again. This sense of detachment could range from mild to extreme, in which your character completely loses awareness of their present surroundings. (Note: Children may re-enact the trauma in play. See ‘Additional Specifications’ at the end for more information about dissociative symptoms.)
  • Intense or drawn-out psychological distress when exposed to reminders of an aspect of the traumatic event. These reminders could be internal (e.g., a physical sensation) or external (e.g., a trigger in the environment) and can resemble the original trauma or symbolise it.
  • Noticeable physiological responses to the above-mentioned internal or external reminders (symbolic or otherwise) of the traumatic event.

Criterion C:


After the traumatic event occurs, your character must persistently avoid stimuli they associate with the event in one or both of these ways:

  • Avoiding or attempting to avoid distressing memories, thoughts or feelings about the traumatic event or something closely associated with it.
  • Avoiding or attempting to avoid external reminders that trigger distressing memories, thoughts or feelings about the traumatic event or something closely associated with it. These reminders could be people, places, conversations, activities, objects, situations, and so on.

Criterion D:

Negative Changes to Thoughts and Mood

Negative changes linked to the traumatic event must occur to your character’s thoughts and mood, starting or (if they were already present) worsening after the traumatic event, in two or more of these ways:

  • An inability to remember an important aspect of the trauma. This is usually caused by dissociative amnesia and not by other factors like a head injury, alcohol or drugs (in other words, amnesia caused by psychological rather than physiological factors).
  • Persistent and exaggerated negative beliefs or expectations about themselves, others or the world. For example, “No one can be trusted. The world is completely dangerous.”
  • Persistent, distorted thoughts about the cause or consequences of the traumatic event, which leads your character to blame themselves or others.
  • A persistent negative emotional state, such as fear, anger, horror, guilt or shame.
  • A noticeable decrease in interest or participation in significant activities.
  • Feelings of detachment, alienation or estrangement from others.
  • A persistent inability to feel positive emotions, such as happiness, satisfaction or loving feelings.

Criterion E:

Hyperarousal and Hypervigilance

Noticeable changes in arousal (alertness) and reactivity (reactions) associated with the traumatic event, starting or worsening after the trauma, in two or more of these ways:

  • Angry outbursts (with little or no provocation) or irritable behaviour, usually expressed through verbal or physical aggression towards others or objects.
  • Behaving recklessly or in a self-destructive way.
  • Hypervigilance—constantly being tense and on guard.
  • An exaggerated startle response.
  • Problems with concentration.
  • Sleep disturbance, such as restless sleep, difficulty getting to sleep or problems staying asleep.

Related post: What Happens to Sleep Deprived Characters?

Criterion F:


To be diagnosed with PTSD, your character must have experienced Criteria B, C, D and E (referred to collectively as the ‘disturbance’) for more than one month.

Criterion G:


The disturbance must cause your character clinically significant distress or impairment in social, job-related or other important areas of functioning. In other words, having the symptoms isn’t enough to be diagnosed; they have to cause problems in your character’s life.

Criterion H:


The disturbance (i.e., Criteria B to E) is not caused by the physiological effects of a substance, such as medication or alcohol, or another medical condition.

Additional Specifications

When diagnosing PTSD, the previously mentioned criteria for dissociative symptoms (e.g., the dissociative reactions in Criterion B3) must be met, as well as this additional point. Your character must also experience persistent or recurring symptoms in response to triggers of either of the following:

  • Depersonalisation: Your character feels persistently or repeatedly detached from their mental processes or body, as if they are an outside observer looking in. For example, they might feel a sense of unreality of their self or body, or feel as if they are in a dream or that time is moving slowly.
  • Derealisation: Your character feels a persistent or recurring sense of unreality of their surroundings. For example, they may feel that the world around them is unreal, dream-like, distant or distorted.

So that’s how Post-Traumatic Stress Disorder is diagnosed… but what exactly do all these criteria mean and how can you write about them in a story? You can find the translations, applications and a free workbook in the next couple of posts, starting with Getting It Right: Writing About Post-Traumatic Stress Disorder.