Intrusive memories of hallucinations and delusions in traumatized intensive care patients: An interview study

Objective: Psychological morbidity, including post-traumatic stress disorder (PTSD), is common in survivors of intensive care. Intrusive memories of trauma are important symptoms of PTSD. Research has not established which aspects of intensive care are most traumatizing; invasive medical procedures, fear of dying from life-threatening illness or injury, or effects of psychoactive drugs, including hallucinations and delusions. Our study aimed to investigate the roots of post-intensive care trauma by interviewing survivors with symptoms of PTSD. Were their intrusive memories primarily of real events or hallucinations and delusions from intensive care?

Design: Interview study as part of a mixed-methods investigation of psychological outcomes post-intensive care.

Methods: We used purposive sampling to identify patients with intrusive memories of intensive care unit. Detailed interviews were conducted to investigate the nature and content of post-intensive care memories. Intrusive memories were categorized as factual, hallucinatory/delusional, or uncertain.

Results: Thematic saturation was achieved after 17 interviews. Approximately 70% (12/17) of patients had hallucinatory/delusional intrusive memories of intensive care, while 12% (2/17) had factual but no hallucinatory/delusional memories; 18% (3) were uncertain whether memories were factual or hallucinatory/delusional. Further analysis suggested that 88% of all patients had hallucinatory/delusional intrusive memories. The content of intrusive memories commonly merged realistic events (involving intensive care staff, environment, medical procedures and unpleasant physical experiences) with delusions and frightening hallucinations.

Conclusions: We found that patients in this in-depth study were more traumatized by frightening hallucinations/delusions than real events, suggesting they may have post-psychosis PTSD, rather than classic PTSD. Interventions are needed to diagnose and treat intensive care hallucinations/delusions, or minimize effects, to prevent PTSD.