A leading US emergency doctor, overwhelmed by the sheer number of patients presenting with COVID-19, has become the latest healthcare worker to take her own life, leading an Australian expert to warn of post-traumatic stress disorder among frontline workers.

Dr Lorna Breen, 49, the medical director of New York-Presbyterian Allen Hospital’s emergency department, died after being “crushed” by the weight of COVID-19 cases, says her family.

Dr Breen, who had no history of depression, contracted the viral illness and returned to work after just a week and a half, but ran out of “emotional gas”, according to her father Philip Breen, who is also a doctor.

“The last time I talked to her was before she went in for her 12-hour shift that she couldn’t finish,” he said.