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. Statement of contribution What is already known on this subject? It is known that there are elevated rates of post-traumatic stress disorder (PTSD) and other psychological morbidity after intensive care. It has been suggested that the intensive care experience has a troubling impact on patient memory that may be associated with PTSD, but the nature of the memory problems and their role in post-intensive care PTSD is not well defined or understood. It is not understood which are the most traumatizing aspects of intensive care that may lead to the development of PTSD. What does this study add? This detailed interview study showed that patients suffered intrusive memories (emotionally arousing memories that repeatedly intrude into people’s minds) related to intensive care up to 8 months after leaving the intensive care unit (ICU). The content of intrusive memories merged factual memories from the ICU, such as pain, bleeding and choking, with hallucinatory, delusional memories such as persecution, conspiracy, religious cults, zombies, aliens, trials and torture. In this study, intrusive memories were more commonly of hallucinations and delusions experienced in the ICU, rather than factual events from intensive care, suggesting a syndrome such as post-psychosis PTSD. Hallucinations and delusions, rather than factual events, were the most traumatizing aspects of intensive care among this group of patients and may have led to the development of PTSD.