While neuropsychologists Erin Kaseda and Andrew Levine were researching the possibility of hospitalized Covid-19 patients developing post-traumatic stress disorder (PTSD), they heard reports of patients experiencing vivid hallucinations. Restrained by ventilators and catheters, delirious from medication and sedatives and confused by the changing cast of medical professionals cycling through the ward, intensive care unit (ICU) patients are especially prone to trauma. For Covid-19 ICU patients, a combination of factors, including side effects of medication, oxygenation issues and possibly the virus itself, can cause delirium and semi-consciousness during their hospital stay. Kaseda says as these patients slip in and out of consciousness, they may visualize doctors wheeling their bodies to a morgue or see violent imagery of their families dying. Such instances, though imagined, can cause trauma that may lead to PTSD in patients long after they have physically recovered from Covid-19.