Mental health needs associated with COVID-19 on the diamond princess cruise ship: A case series recorded by the disaster psychiatric assistance team.

Coronavirus disease 2019 (COVID-19) infection prevention measures have led to a variety of mental health issues. Although several self-care methods have been recommended for those quarantined, evidence regarding how best to support quarantined people experiencing a mental health crisis is limited. In February 2020, the Diamond Princess cruise ship was quarantined in Yokohama port, Japan following a passenger testing positive for COVID-19. We were sent to address the mental health issues as the Disaster Psychiatric Assistance Team (DPAT). In the present study, we examined the acute mental health needs of the passengers and crew collected by the DPAT using the standard Emergency Medical Team daily reporting system. We assessed 206 cases (99 men and 107 women) with generic health issues and 127 cases (39 men and 88 women) with mental health issues. Mental health issues including disaster stress-related symptoms were as frequent as physical health events associated with COVID-19. The most significant mental health issue was anxiety, as an acute psychological reaction to the quarantine situation. Women and crews most frequently needed mental health support. Mental health improved in most clients after brief counseling. Although several passengers experienced suicidal ideation, there were no cases of actual suicide attempts during the quarantine period. This case has been regarded as a well-known public health event at the beginning of the COVID-19 era. In addition to physical health support, disaster mental health support was essential to save lives. Our findings may facilitate responses to future quarantines, accidents, and mental health crises.

Introduction

The coronavirus disease 2019 (COVID-19) pandemic has been an unprecedented disaster worldwide; over 500 million people have been infected by the virus and there have been about 6 million confirmed deaths (although the estimated number exceeds 18 million) between Jan 1, 2020, and Dec 31, 2021 [1]. COVID-19 can induce a variety of mental health problems such as fear, anxiety, depression, and post-traumatic stress symptoms, among others [2]. These symptoms may appear because of the infection itself, as well in relation to infection prevention measures including quarantine, lockdown, and social distancing. In particular, quarantine, which involves isolating people who have been exposed to a contagious disease to prevent the spread of infection has frequently been implemented and can result in loneliness and negative psychological sequelae [3]. Although several self-care methods have been recommended for those in quarantine, evidence of how best to support quarantined people experiencing a mental health crisis is limited. Such crises were first noted among passengers aboard the Diamond Princess cruise ship [4].

From February 5 to 23, 2020, the Diamond Princess cruise ship was quarantined at Yokohama port, Japan. There were 3,711 people onboard, including 2,666 passengers and 1,045 crew members. The ship was quarantined by the Japanese government after a passenger who disembarked in Hong Kong was found to be infected with COVID-19. Over 2,600 passengers from 56 countries were scheduled to disembark the ship on February 5 but were instead isolated in their cabin rooms for 14 days to prevent further spread of the disease [4,5] (Fig. 1 ).

Fig. 1

Photograph of the Diamond Princess cruise ship quarantined at Yokohama port on February 12, 2020.

During the quarantine period, the isolated crew and passengers faced many difficulties related to infection control [6], as well as physical [7] and psychological problems [8]. The number of confirmed COVID-19 cases steadily increased, and international media were frequently critical of the response of the Japanese government. Several passengers requested (via social media) to return to their home countries. On February 17, the US government used charter planes to evacuate US citizens who wanted to return to the US [9].

To respond to the mental health needs of the passengers and crew, we came aboard the Diamond Princess as the Disaster Psychiatric Assistance Team (DPAT) and conducted mental health and psychosocial support activities. The ship carried members of the DPAT [10], as well as other Emergency Medical Teams (EMTs) including the Japanese Disaster Medical Assistance Team (DMAT), Japan Medical Association Team (JMAT), Japanese Red Cross Team, and Disaster Infection Control Team, on request of the Japanese Ministry of Health, Labour and Welfare [11]. Mental health support services delivered by the DPAT included the provision of personal protective equipment and psychiatric treatment including counseling, medication, and triage. The ship's crew and medical team also received assistance from the DPAT. The 14-day quarantine period was completed on February 19. By March 1, all passengers and crew had disembarked from the ship. In total, 712 passengers and crew members tested positive for COVID-19 [12]. The DPAT carried out support activities from February 9 to 21. Fifty-five members of 12 DPAT groups joined the mission, and one member was unfortunately infected with COVID-19 during the activity.

The quarantine of the Diamond Princess was the most famous emergency response to the spread of COVID-19 on a cruise ship. Although mental health issues have been reported for previous infection disease outbreaks, such as SARS [13] and MERS [14], the Diamond Princess case was the largest disaster of this nature to involve international passengers. Japanese efforts on the ship provoked international concerns [15]. There were significant issues regarding the quarantine process, including in relation to infection control [16], patient transportation [17], ethical justice [5], and the mental health of isolated people [8]. These concerns provide important lessons that may help improve international measures during the COVID-19 pandemic. Among them, mental health issues related to quarantine have not been fully examined. Therefore, in the present study, we collected data from the passengers and crew of the Diamond Princess, who were supported by the DPAT and other EMTs, to assess the clinical characteristics of those with acute mental health needs on the quarantined ship and recommend evidence-based measures for disaster mitigation.

Methods

The cases in the present study were the passengers and crew of the Diamond Princess, who received mental and physical care from members of the DPAT, DMAT, or JMAT from February 9 to 21, 2020. Case data were collected from an anonymized database generated using the standard EMT daily reporting form known as The Japan Surveillance in Post Extreme Emergencies and Disasters (J-SPEED). All EMTs used the J-SPEED to support a data-based operation policy [18].

There are two versions of the J-SPEED daily reporting form: a generic (physical) version and a mental health version. The former was developed to evaluate physical or general medical support provided by EMTs, such as that provided by the DMAT and JMAT. The latter was developed to enable specific evaluation of the mental health care needs addressed by the DPAT. The J-SPEED data recording process is simple; it involves a check list in the style of the World Health Organization mini data set (WHO-MDS) for EMTs, and only current symptoms are considered [19]. The form used in this study for recording mental health symptoms is shown in Fig. 2 . Data collected in the physical health version include sex, age, and health events including trauma, fever, acute respiratory infection, digestive infectious diseases, disaster-stress related symptoms, urgent mental care needs, general health conditions including hypertension, and medical/surgical emergencies. In the mental health version, the data collected included sex, age, mental health events including anxiety, insomnia, depression, anger, suicidal ideation, somatic symptoms, excitement, incontinent speech, scattered speech, flashbacks, paranoid symptoms, amnesia, mutism, self-injury, suicide attempts, and others, and additional information including role on the ship (passenger or crew), stressors (direct stress caused by the COVID-19 pandemic, indirect stress caused by environmental changes mainly related to quarantine, or stress not related to the event), diagnostic category by the International Statistical Classification of Diseases and Related Health Problems 10th version (ICD-10) F code, types of provided support (medication, counseling, or case work), and outcome (finished or continued). Information regarding the psychological complaints of passengers was also collected from members of the DPAT, for a more comprehensive evaluation of the results.

Fig. 2

The mental health version of the J-SPEED/WHO-MDS (excerpt).

All professional mental health support provided by the DPAT on the Diamond Princess was aggregated using the mental health version of the J-SPEED. The medical support provided by the DMAT and JMAT was only recorded during the middle of the activity period; the focus was on triage and transport of COVID-19-positive patients, and there was insufficient time to record their medical needs in J-SPEED. The study inclusion criteria were receipt of support from EMTs and the recording of data in J-SPEED. The exclusion criterion was missing data.

Statistical analyses were performed using SPSS software (ver. 26.0; IBM Corp., Armonk, NY, USA). Demographic (sex, age, and vocation) and clinical characteristics (physical health events, mental health events, stressors, diagnoses, support provided by EMTs, and outcomes) were analyzed using the chi-square test. Residual analysis to identify specific cases driving significant differences was also performed, and Cramer's V was calculated as a measure of the magnitude of the associations between demographic and clinical characteristics (≥0.4, strongly related; 0.25–0.39, related; 0.1–0.24, weakly related; < 0.1, unrelated). Regression analysis and correction for multiple testing were not conducted because the number of cases for certain clinical characteristics was insufficient. P-values < 0.05 and a residual Z value > 1.96 were considered to indicate statistical significance.

The Hiroshima University Ethics Committee examined and approved the ethical procedure used in this study (approval number: E−2059).

Results

Data from 435 consultations were collected using the J-SPEED. Of these, data from 289 cases were recorded by the DMAT using the generic version of the J-SPEED and that from 146 cases were recorded by the DPAT using the mental health version of the J-SPEED. Cases with missing data were excluded from the analysis. A total of 206 cases for the generic version and 127 cases for the mental health version of the J-SPEED were included in the analysis.

Table 1 presents the characteristics of the cases collected using each version of the J-SPEED. In the generic health version, data from 99 men and 107 women were collected. There was no significant sex difference in age distribution. In the mental health version, data from 39 men and 88 women were collected. Data were collected for twice as many women as men (88 vs. 39), and this ratio was substantially different from that for the generic health version of the form (107 vs. 99). The women were significantly younger than the men (χ2 = 9.03, V = 0.267, P = 0.029). Crew members comprised 15 (11.8%) of the clients assessed using the mental health version of the form. There was no significant difference in sex distribution between the passengers and crew.

Table 1

Characteristics of cases according to the J-SPEED data.

	Physical Health version						Mental Health version
Characteristics	No. (%)			χ2	V	P	No. (%)			χ2	V	p
	Total	Men	Women				Total	Men	Women
Age
1–14 yrs.	1 (0.5)	1 (1)	0 (0)	4.81	0.153	0.186	1 (0.7)	1 (2.6)	0 (0)	9.03	0.267	0.029
15–64 yrs.	100 (48.5)	41 (41.4)	59 (55.1)				63 (49.6)	13 (33.3)	50 (56.8)**
over 65 yrs.	93 (45.1)	51 (51.5)	42 (39.3)				52 (40.9)	19 (48.7)	33 (37.5)
Unknown	12 (5.8)	6 (6.1)	6 (5.6)				11 (5.3)	6 (15.4)	5 (5.7)
Role
Passengers	*	*	*				112 (88.2)	36 (91.7)	76 (86.4)	0.92	0.085	0.338
Crews	*	*	*				15 (11.8)	3 (8.3)	12 (13.6)
Total	206 (100)	99 (100)	107 (100)				127 (100)	39 (100)	88 (100)

*Data not available; **residual Z > 1.96; p: p-value; V: Cramer's V.

Table 2 presents all health events collected by the DMAT and JMAT using the generic physical health version of the J-SPEED. “Fever” was the most common health event (83 [34%]), followed by “Disaster stress-related symptoms” (63 [27.9%]), “Acute respiratory infection” (48 [19.7%]), and “Urgent mental healthcare needs” (22 [9%]). Fever was significantly more frequent in men than women (χ2 = 6.63, V = 0.123, P = 0.011). In contrast, disaster-related symptoms were more frequent in women than men (χ2 = 13.95, V = 0.179, P < 0.001). Health event frequency did not differ significantly according to age.

Table 2

Health events recorded using the generic health version of J-SPEED.

	Total, No. (%)	Sex					Age
Health Events		No. (%)		χ2	V	p	No. (%)			χ2	V	p
		Men	Women				15–64yrs.	Over 65yrs.	Unknown
Fever	83 (34)	51 (45.5)*	31 (23.7)	6.63	0.123	0.011	44 (37.6)	37 (33)	2 (14.3)	6.09	0.118	0.108
Disaster stress related symptoms	68 (27.9)	19 (17)	49 (37.4)*	13.95	0.179	<0.001	38 (32.5)	28 (25)	2 (14.3)	5.95	0.117	0.114
Acute respiratory infection	48 (19.7)	26 (23.2)	22 (16.8)	0.64	0.038	0.447	21 (17.9)	20 (17.9)	6 (42.9)	3.73	0.093	0.292
Urgent mental care needs	22 (9)	7 (6.3)	15 (11.5)	2.65	0.078	0.103	8 (6.8)	11 (9.8)	3 (21.4)	2.52	0.076	0.471
Hypertension	8 (3.3)	3 (2.7)	5 (3.8)	0.41	0.031	0.521	1 (0.9)	7 (6.3)	0 (0)	5.13	0.109	0.163
Diseases not listed	7 (2.9)	2 (1.8)	5 (3.8)	1.16	0.052	0.282	3 (2.6)	4 (3.6)	0 (0)	0.68	0.040	0.878
Urgent infectious disease response needs	3 (1.2)	1 (0.9)	2 (1.5)	0.29	0.026	0.592	1 (0.9)	1 (0.9)	1 (7.1)	3.65	0.092	0.301
Digestive infectious diseases	2 (0.8)	2 (1.8)	0 (0)	2.11	0.070	0.237	0 (0)	2 (1.8)	0 (0)	2.17	0.071	0.537
Urgent medical care needs besides infectious diseases	2 (0.8)	1 (0.9)	1 (0.8)	0.00	0.002	0.971	0 (0)	2 (1.8)	0 (0)	2.17	0.071	0.537
Head/spine injury	1 (0.4)	0 (0)	1 (0.8)	0.95	0.047	0.329	1 (0.9)	0 (0)	0 (0)	1.27	0.054	0.737

*residual Z > 1.96; p: p-value; V: Cramer's V.

Table 3, Table 4 present detailed data from the mental health version of the J-SPEED. As shown in Table 3, “Anxiety” was the most common event (81 [32.9%]), followed by “Insomnia” (37 [15.0%]), “Other” (36 [14.6%]), “Depression” (24 [9.8%]), “Anger” (18 [7.3%]), “Suicidal ideation” (14 [5.7%]), “Somatic symptoms” (11[4.5%]), and “Excitement” (11 [4.5%]). Anxiety was the most frequent event for individuals of both genders and all ages. Actual complaints of anxiety from passengers were varied and included statements such as: “I am afraid to test positive,” “I am scared that the infection has already spread to the whole ship,” “I have not been given a test for infection because I have no fever or symptoms of the virus. I have repeatedly requested to have an examination, but every crew member told me to wait. I am feeling very anxious,” and “I find it unbearable to be quarantined. I wonder when we will be released.”

Table 3

Mental health events for cases recorded using the mental health version of the J-SPEED.

		Sex					Age						Role
		No. (%)		χ2	V	p	No. (%)			χ2	V	p	No. (%)		χ2	V	p**
Mental Health Events	Total, No. (%)	Men	Women				15–64yrs.	Over 65yrs.	Unknown				Passengers	Crews
Anxiety	81 (32.9)	19 (33.9)	62 (32.6)*	25.46	0.242	<0.001	33 (25.8)	42 (40.8)	6 (40)	2.08	0.069	0.556	79 (36.9)	2 (6.3)	0.29	0.026	0.748
Insomnia	37 (15)	8 (14.3)	29 (15.3)*	11.90	0.165	0.001	23 (18)	13 (12.6)	1 (6.7)	5.81	0.116	0.121	27 (12.6)	10 (31.3)*	67.53	0.394	<0.001
Others	36 (14.6)	15 (26.8)	21 (11.1)	0.79	0.042	0.376	21 (16.4)	10 (9.7)	5 (33.3)	7.04	0.127	0.071	32 (15)	4 (12.5)*	6.92	0.126	0.028
Depression	24 (9.8)	5 (8.9)	19 (10)*	7.92	0.135	0.005	15 (11.7)	9 (8.7)	0 (0)	4.51	0.102	0.211	21 (9.8)	3 (9.4)*	6.25	0.120	0.043
Angry	18 (7.3)	4 (7.1)	14 (7.4)*	5.28	0.110	0.022	13 (10.2)	4 (3.9)	1 (6.7)	6.24	0.120	0.100	14 (6.5)	4 (12.5)*	19.88	0.214	0.002
Suicide ideation	14 (5.7)	1 (1.8)	13 (6.8)*	10.02	0.152	0.002	4 (3.1)	9 (8.7)	1 (6.7)	1.80	0.064	0.615	14 (6.5)	0 (0)	0.52	0.034	1.000
Somatic symptoms	11 (4.5)	0 (0)	11 (5.8)*	10.73	0.157	0.001	2 (1.6)	9 (8.7)	0 (0)	5.28	0.110	0.152	11 (5.1)	0 (0)	0.40	0.030	1.000
Excitement	11 (4.5)	2 (3.6)	9 (4.7)*	4.22	0.098	0.040	6 (4.7)	4 (3.9)	1 (6.7)	0.88	0.045	0.831	11 (5.1)	0 (0)	0.40	0.030	1.000
Incontinent speech	5 (2)	0 (0)	5 (2.6)	3.84	0.094	0.050	5 (3.9)	0 (0)	0 (0)	5.11	0.108	0.164	1 (0.5)	4 (12.5)*	89.03	0.510	<0.001
Scattered speech	4 (1.6)	0 (0)	4 (2.1)*	4.81	0.105	0.028	4 (3.1)	0 (0)	0 (0)	6.40	0.121	0.094	0 (0)	4 (12.5)*	113.04	0.452	<0.001
Flash back	1 (0.4)	0 (0)	1 (0.5)	0.95	0.047	0.329	1 (0.8)	0 (0)	0 (0)	1.27	0.054	0.737	0 (0)	1 (3.1)*	28.07	0.254	0.034
Paranoid symptoms	1 (0.4)	0 (0)	1 (0.5)	0.95	0.047	0.329	0 (0)	1 (1)	0 (0)	1.08	0.050	0.781	1 (0.5)	0 (0)	0.04	0.009	1.000
Amnesia	1 (0.4)	1 (1.8)	0 (0)	1.05	0.049	0.305	0 (0)	1 (1)	0 (0)	1.08	0.050	0.781	1 (0.5)	0 (0)	0.04	0.009	1.000
Mutism	1 (0.4)	1 (1.8)	0 (0)	1.05	0.049	0.305	0 (0)	1 (1)	0 (0)	1.08	0.050	0.781	1 (0.5)	0 (0)	0.04	0.009	1.000
Self-injury	1 (0.4)	0 (0)	1 (0.5)	0.95	0.047	0.329	1 (0.8)	0 (0)	0 (0)	1.27	0.054	0.737	1 (0.5)	0 (0)	0.04	0.009	1.000
Suicide attempt	0 (0)	0 (0)	0 (0)	N/A	N/A	N/A	0 (0)	0 (0)	0 (0)	N/A	N/A	N/A	0 (0)	0 (0)	N/A	N/A	N/A

*: residual Z > 1.96; p: p-value; V: Cramer's V.

Table 4

Stressors, diagnoses, support, and outcomes, recorded using the mental health version of J-SPEED.

		Sex					Age						Role
		No. (%)		χ2	V	p	No. (%)			χ2	V	p	No. (%)		χ2	V	p
Category	Total, No. (%)	Men	Women				15–64yrs.	over65yrs.	Unknown				Passengers	Crews
Quarantine	60 (70.6)	13 (59.1)	45 (75)*	17.98	0.203	<0.001	27 (65.9)	29 (78.4)	2 (50)	2.20	0.071	0.531	51 (73.9)	7 (53.8)*	14.20	0.180	0.002
COVID-19	24 (28.2)	8 (36.4)	15 (25)	1.28	0.054	0.298	14 (34.1)	7 (18.9)	2 (50)	3.94	0.095	0.268	17 (24.6)	6 (46.2)*	35.44	0.285	<0.001
Others	1 (1.2)	1 (4.5)	0 (0)	1.05	0.049	0.487	0 (0)	1 (2.7)	0 (0)	1.08	0.050	0.781	1 (1.4)	0 (0)	0.04	0.009	0.85
Reaction to severe stress and adjustment disorders (F43)	41 (83.7)	8 (88.9)	33 (82.5)*	15.47	0.189	<0.001	28 (93.3)*	13 (68.4)	0 (0)	12.04	0.166	0.007	27 (79.4)	14 (93.3)*	128.13	0.543	<0.001
Depressive Episode (F32)	5 (10.2)	0 (0)	5 (12.5)	4.81	0.105	0.061	2 (6.7)	3 (15.8)	0 (0)	0.57	0.036	0.904	4 (11.8)	1 (6.7)	4.16	0.098	0.162
Unspecified Dementia (F03)	2 (4.1)	1 (11.1)	1 (2.5)	0.00	0.002	0.971	0 (0)	2 (10.5)	0 (0)	2.17	0.071	0.537	2 (5.9)	0 (0)	0.07	0.013	0.789
Somatoform disorders (F45)	1 (2)	0 (0)	1 (2.5)	N/A	N/A	N/A	0 (0)	1 (5.3)	0 (0)	N/A	N/A	N/A	1 (2.9)	0 (0)	N/A	N/A	N/A
Counseling and advise	115 (87.8)	35 (92.1)	80 (86)*	20.96	0.219	<0.001	53 (81.5)	53 (94.6)	9 (90)	2.88	0.081	0.410	106 (92.2)	9 (56.3)*	9.00	0.144	0.005
Medication	13 (9.9)	3 (7.9)	10 (10.8)	3.53	0.090	0.089	10 (15.4)	2 (3.6)	1 (10)	6.46	0.122	0.091	6 (5.2)	7 (43.8)*	102.20	0.485	<0.001
Case work including admission	3 (2.3)	0 (0)	3 (3.2)	1.91	0.066	0.167	2 (3.1)	1 (1.8)	0 (0)	0.17	0.020	0.982	3 (2.6)	0 (0)	0.07	0.013	0.789
Improved	89 (65.9)	16 (51.6)	63 (67)*	17.07	0.198	<0.001	47 (73.4)	31 (52.5)*	11 (91.7)	10.03	0.152	0.018	85 (69.1)	4 (33.3)	0.37	0.029	0.521
Continued	46 (34.1)	15 (48.4)	31 (33)*	5.36	0.111	0.028	17 (26.6)	28 (47.5)	1 (8.3)	4.52	0.102	0.210	38 (30.9)	8 (66.7)*	30.04	0.263	<0.001

*: residual Z > 1.96; p: p-value; V: Cramer's V.

Women had more (and more diverse) symptoms than men. Anxiety (χ2 = 25.46, V = 0.242, P < 0.001), insomnia (χ2 = 11.90, V = 0.165, P = 0.001), depression (χ2 = 7.92, V = 0.135, P = 0.005), anger (χ2 = 5.28, V = 0.110, P = 0.022), suicidal ideation (χ2 = 10.02, V = 0.152, P = 0.002), somatic symptoms (χ2 = 10.73, V = 0.157, P = 0.001), excitement (χ2 = 4.22, V = 0.098, P = 0.040), and scattered speech (χ2 = 4.81, V = 0.105, P = 0.028) were significantly more frequent in women than men. One older female passenger cried and said, “My husband was found to have COVID-19 and taken to the hospital three days ago. Since then, I have not had any contact with him by telephone. The hospital will not permit me to talk with him because of privacy concerns. I have been left alone in this room and feel severely depressed. From the balcony in this room, I can see my home in Yokohama city, but I cannot go back to our home. I will want to die by jumping from the balcony if my husband dies without being able to speak with me. This voyage was supposed to be a happy ending for us. But now, it might become a bad end.”

Mental health event frequency did not differ significantly by age. Crew members had significantly more mental health events than passengers, including insomnia (χ2 = 67.53, V = 0.394, P = 0.001), “other” (χ2 = 6.92, V = 0.126, P = 0.028), depression (χ2 = 6.25, V = 0.120, P = 0.043), anger (χ2 = 19.88, V = 0.214, P = 0.002), incontinent speech (χ2 = 89.03, V = 0.510, P < 0.001), scattered speech (χ2 = 113.04, V = 0.452, P < 0.001), and flashbacks (χ2 = 28.07, V = 0.254, P = 0.034). A staff member in the medical center of the ship said, “We must save all passengers; this is my duty. I have no time to sleep.” She seemed to be exhausted and approaching burnout.

The main stressors, diagnoses, support types by DPAT, and outcomes of cases are shown in Table 4. In terms of stressors, “Quarantine” (60 [70.6%]) was more stressful than “COVID-19” overall (24 [28.2%]) and was also more stressful for women than men (χ2 = 17.98, V = 0.203, P < 0.001), and for crew members than passengers (χ2 = 14.20, V = 0.180, P = 0.002). COVID-19 was more stressful for crew members than passengers (χ2 = 35.44, V = 0.285, P < 0.001).

The most common diagnosis (41 [83.7%]) was “Reactions to severe stress and adjustment disorders” (F43 in ICD-10 code), which was also significantly more prevalent among women than men (χ2 = 15.47, V = 0.189, P < 0.001), younger than elderly adults (χ2 = 12.04, V = 0.166, P = 0.007), and crew members than passengers (χ2 = 128.13, V = 0.543, P < 0.001). Although they were relatively rare, depressive episodes, unspecified dementia, and somatoform disorders were diagnosed in individuals of both sexes, elderly individuals, and passengers.

The most frequent type of support provided to clients was “Counseling and advice” (115 [87.8%]); it was also more frequently provided for women than men (χ2 = 20.96, V = 0 0.219, P < 0.001) and crew members than passengers (χ2 = 9.00, V = 0.144, P = 0.005). Counseling and advice from DPAT were provided as “psychological first aid (PFA)” [20]. “Medications” were taken more frequently by crew members than passengers (χ2 = 102.20, V = 0.485, P < 0.001).

The outcome of 89 cases (65.9%) was classified as “Finished”, i.e., mental health symptoms improved immediately following support from DPAT provided during a single session. The Finished outcome was more common for women than men (χ2 = 17.07, V = 0.198, P < 0.001), and for elderly than young adults (χ2 = 10.03, V = 0.152, P = 0.018). Cases who needed continuous support were significantly more likely to be women than men (χ2 = 5.36, V = 0.111, P = 0.028), and to be crew members than passengers (χ2 = 30.04, V = 0.263, P < 0.001). There were no cases of suicide attempts, violence, or mass panic.

Discussion

The goal of this case series was to report on the mental health needs of passengers and crews aboard the quarantined Diamond Princess cruise ship in Japan. To our knowledge, no previous reports have examined mental health issues among passengers and crew members on a quarantined ship.

Overall, our results indicated that mental health issues including disaster stress-related symptoms were the second most frequent health-related event after COVID-19 infection. The most significant mental health event was anxiety as an acute psychological reaction to the quarantine situation. Women and crews were the most vulnerable groups in need of mental health support. Most mental health events were improved by brief counseling. Some individuals needed psychotropic medications or continued support. Although several passengers reported experiencing suicidal ideation, there were no cases of suicide attempts, violence, or mass panic.

Since the first wave of the worldwide COVID-19 pandemic, many studies have repeatedly demonstrated its significant psychological impact on public health [[21], [22], [23], [24]]. Even then, it is surprising that mental health needs were as frequent as health needs related to COVID-19 on the quarantined ship. Anxiety was the most frequent symptom among the passengers surveyed in this study. Previous studies reported acute stress disorder, post-traumatic stress disorder, depression, distress, fear, and boredom as psychological symptoms caused by quarantine; anxiety was less prevalent than PTSD symptoms [3,25]. While TV news and updates from the captain of the ship informed the passengers of the increasing numbers of infected cases each day, they did not provide assistance regarding how to cope with isolation. Communication with the outside world was limited as personal communication tools such as smartphones had poor service in the port. The phone line for room service was frequently occupied because many of the passengers wanted to talk or make requests for food, cleaning services, bathing supplies, and other hospitality services. These confused special situations might induce anxiety as most frequent events in many passengers on the quarantined ship.

Another significant finding was that women were more likely to have severe psychological symptoms than men, including insomnia, depression, somatic symptoms, scattered speech, and suicidal ideation, as well as excitement. Women have frequently been found to have more psychological symptoms, including depression, than men, and this tendency was observed in the immediate psychological response of the general population during the COVID-19 epidemic [26,27]. Greater efforts to enable communication, as well as empathy for people in such situations may help maintain social connections and prevent suicide attempts. Family separation is a critical issue when mitigating mental health issues.

The crew members were more likely than passengers to experience insomnia, depression, anger, and incontinent or scattered speech. There have been several reports of fatigue, boredom, and depression among those stranded on vessels during the COVID-19 pandemic [28]. The crew members surveyed in our study included medical center staff, who reported being overworked and had to respond to the physical and psychological complaints of passengers without personal protective equipment. In many previous studies, medical health workers reported insomnia, anxiety, burnout, PTSD, and moral injury [29,30]. Therefore, crew members of quarantined ships require targeted mental health support.

About 90% of the support provided by the DPAT in this study was counseling as PFA, and symptoms were improved immediately in about 70%| of cases following a single visit from the DPAT. Most of the passengers were alone in their rooms and were extremely appreciative of our visit; their anxiety was improved merely by a brief communication. Psychological First Aid (PFA), as a simple intervention, aims to improve safety, address practical needs, enhance coping, reduce intense distress, and make people aware of additional resources; those at risk of psychopathology can also be identified. The COVID-19 pandemic differs from other disasters in terms of the type, duration, and extent of the threat that it poses [31]. Our results suggest that disaster-related mental health teams, such as the DPAT, as well as basic mental support programs such as PFA, are essential to support the mental health of those in quarantine [32]. Face-to-face communication is also important to reduce the frequency of mental health events [3,12,22].

This study has several limitations. First, the study cases were limited to a group of individuals who independently requested health support. Therefore, our findings may not be generalizable to all passengers and crew on the ship. Second, samples were collected from the J-SPEED database, which was used by EMTs during the mission, and some data may be missing or inaccurate. Third, data regarding the medical support provided by the DMAT and JMAT were only collected during the middle of the activity period. Fourth, more women than men were analyzed, since counseling was requested more frequently by women than men. Fifth, each health event was recorded as an individual response. Thus, the number of health events did not reflect the number of individuals who requested assistance.

In conclusion, we examined data generated by DPATs regarding health issues on the Diamond Princess cruise ship and found that mental health issues were as frequent as COVID-19 infection. The most frequent mental health problem was anxiety, as an acute psychological reaction to the quarantine situation. Women and crew were vulnerable groups who needed mental health support. Disaster mental health services such as DPATs is essential companions to medical services for the maintenance of public health during crisis situations. Our findings pertaining to the mental health issues experienced onboard the Diamond Princess cruise ship shed light on psychological responses to disease outbreaks on quarantined ships.

Funding

This paper comprises a part of “A Study on Activity periods and Quality Activity of Disaster Psychiatric Assistance Teams (DPATs)” that received support from the fiscal year 2021–2022, Japanese Government of Ministry of Health Labor and Welfare Scientific Research Fund (Issue number: 21IA1301).

Declaration of competing interest

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.