In February 2020, as the world began to realize the scope of COVID-19, Japanese authorities quarantined all 3,711 passengers and crew on the Diamond Princess cruise ship for 14 days after a passenger who disembarked earlier in the ship's journey tested positive for COVID-19. A Disaster Psychiatric Assistance Team was sent onto the ship to address the mental health needs of those on board, and recently reported their findings in the International Journal of Disaster Risk Reduction.

The research team found that the frequency of mental health issues was second only to that of COVID-19 infection during the quarantine, in which over 700 people contracted the respiratory illness. The most common mental health issue was anxiety, which was more often related to the quarantine situation than to COVID-19 itself. Other common symptoms included insomnia and depression.

Fortunately, around 70% of the mental health issues were resolved by one brief, in-person counseling session, although some people also required medication or ongoing support. Notably, no severe outcomes (such as suicide) occurred during the quarantine period.

"One key finding was that mental health issues were more common in crew members than in passengers," says Professor Hirokazu Tachikawa, lead author of the study. "Many of the crew members who sought assistance were involved in onboard health care and seemed exhausted and close to burnout, with relatively high rates of insomnia, depression and anger."

Furthermore, in both crew and passengers, women were more likely than men to experience mental health issues on the quarantined ship. This is similar to the higher incidence of mental health issues experienced by women in the general population.

"Our findings of specific groups—in this case, women and crew members—who were more vulnerable to mental health issues on the ship are really important for disaster planning," says Professor Tachikawa. "They highlight the need for targeted mental health support for vulnerable groups in quarantine situations."

Although there are some limitations to the study—for example, only people who requested support during the middle phase of the quarantine period were included in the study sample—the results shine a light on the importance of mental health support, ideally in the form of in-person counseling, in disaster responses. Responding to mental as well as physical health needs during any similar crises will be important for maintaining public health.