How many symptoms of PTSD are there?

The Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) lists 20 symptoms of post-traumatic stress disorder (PTSD). These symptoms are divided into four clusters:

* Cluster A: Re-experiencing symptoms

* Flashbacks

* Nightmares

* Intrusive thoughts

* Emotional reactivity

* Cluster B: Avoidance symptoms

* Avoidance of thoughts, feelings, or situations associated with the trauma

* Emotional numbing

* Restricted range of affect

* Detachment from others

* Cluster C: Hyperarousal symptoms

* Increased startle response

* Difficulty concentrating

* Hypervigilance

* Insomnia

* Irritability

* Aggression

* Cluster D: Negative alterations in cognitions and mood

* Negative beliefs about oneself, others, or the world

* Hopelessness

* Guilt or shame

* Loss of interest in activities

* Difficulty experiencing positive emotions

Not everyone who experiences trauma will develop PTSD. However, the more severe the trauma, the more likely it is that someone will develop PTSD.