PTSD

Post-traumatic stress disorder: from 'shell shock' to modern diagnosis, intrusive memories and hypervigilance, fear circuits that fail to switch off, and trauma-focused therapies that work.

A long history under different names

Descriptions of lasting distress after combat go back to ancient texts. In the First World War, soldiers with tremors, nightmares and paralysis were said to have "shell shock"; in the Second, "combat fatigue". Post-traumatic stress disorder (PTSD) entered the DSM in 1980, influenced by Vietnam veterans' advocacy, and was recognised as affecting survivors of many kinds of trauma: assault, abuse, accidents, disasters and violence.

Symptoms

PTSD involves four clusters lasting more than a month after trauma. Intrusions: unwanted memories, flashbacks that feel like reliving the event, nightmares. Avoidance of reminders, places, people or thoughts. Negative changes in thinking and mood: guilt, shame, detachment, inability to feel positive emotions. Arousal and reactivity: hypervigilance, exaggerated startle, irritability, poor sleep and concentration. Most people exposed to trauma do not develop PTSD; distress often fades naturally over weeks.

The brain

PTSD has been described as a disorder of fear memory and its regulation. Brain imaging studies find, on average, a hyper-responsive amygdala, reduced activity in the ventromedial prefrontal cortex that normally inhibits fear, and differences in the hippocampus, which places memories in context — so that cues can trigger fear as if the danger were present now, regardless of setting. Smaller hippocampal volume has been found in some people with PTSD; a study of identical twins suggested it may partly be a pre-existing risk factor rather than only a consequence. People with PTSD often show impaired fear extinction.

Treatment

Trauma-focused psychological therapies have the strongest evidence: prolonged exposure (gradually revisiting the memory and avoided situations), cognitive processing therapy (examining beliefs about the trauma), trauma-focused CBT and EMDR (eye movement desensitisation and reprocessing). SSRIs and SNRIs can help; prazosin is sometimes used for nightmares. In August 2024 the US FDA declined to approve MDMA-assisted therapy for PTSD, requesting another trial, despite promising earlier results; psychedelic-assisted approaches remain under study.