UMIN-CTR Clinical Trial

Public title

A prospective cohort study of long-term predictors of PTSD-related symptoms among new recruits of the Japan Maritime Self-Defense Force

Acronym

JMSDF PTSD Cohort Study

Scientific Title

Gene-environment interaction in post-traumatic stress disorder among Japan Maritime Self-Defense Force personnel: a long-term cohort study

Scientific Title:Acronym

JMSDF PTSD-GxE Cohort Study

Region

Japan

Condition

PTSD-related symptoms and stress-related mental health outcomes

Classification by specialty

Psychiatry

Classification by malignancy

Others

Genomic information

YES

Narrative objectives1

This long-term prospective cohort study will examine new recruits of the Japan Maritime Self-Defense Force. Baseline information on adverse childhood experiences, protective and compensatory experiences, psychological aptitude, self-compassion, and related factors will be integrated with annual mental health check-up and periodic health examination data. The study will explore the effects and interactions of early-life environmental factors, adult-life stress exposure, and genetic factors on the onset and longitudinal course of PTSD-related symptoms and related outcomes, including alcohol use, gambling behavior, and suicide-related events. In selected subsets of participants who consent to saliva collection, salivary DNA-derived genotype and DNA methylation data will also be used.

Basic objectives2

Others

Basic objectives -Others

Exploratory investigation of risk factors, predictors, gene-environment interactions, and longitudinal trajectories

Trial characteristics_1

Exploratory

Trial characteristics_2

Developmental phase

Not applicable

Primary outcomes

The primary outcome is PTSD-related symptoms assessed annually using the Impact of Event Scale-Revised (IES-R). The primary outcome measure is the IES-R total score. Longitudinal changes in the IES-R total score, PTSD high-risk status defined as an IES-R total score of 25 or higher, and the first occurrence of an IES-R total score of 25 or higher during follow-up will be evaluated.

Key secondary outcomes

Key secondary outcomes are psychological and physical stress responses and high-stress status assessed annually using the Brief Job Stress Questionnaire; alcohol use/problem drinking assessed at baseline using the Alcohol Use Disorders Identification Test (AUDIT); gambling behavior/problem gambling assessed at baseline using the Problem Gambling Severity Index (PGSI); suicide-related events, including suicidal ideation, suicide planning, and suicide attempt, assessed at baseline for lifetime and past-12-month occurrence; and physical health indicators obtained from periodic health examinations during follow-up.

Study type

Observational

Basic design

Randomization

Randomization unit

Blinding

Control

Stratification

Dynamic allocation

Institution consideration

Blocking

Concealment

No. of arms

Purpose of intervention

Type of intervention

Interventions/Control_1

Interventions/Control_2

Interventions/Control_3

Interventions/Control_4

Interventions/Control_5

Interventions/Control_6

Interventions/Control_7

Interventions/Control_8

Interventions/Control_9

Interventions/Control_10

Age-lower limit

18

years-old

<=

Age-upper limit

Not applicable

Gender

Male and Female

Key inclusion criteria

1. New recruits of the Japan Maritime Self-Defense Force who enter training units or equivalent settings approved for the implementation of this study during the study period.
2. Individuals who understand the study explanation and provide written informed consent to participate in the study.
3. Individuals who are able to complete the baseline questionnaire and select either "questionnaire only" or "questionnaire plus saliva sample collection using Oragene" as their mode of participation.
4. Individuals aged 18 years or older at enrollment.

Key exclusion criteria

1. Individuals who do not provide consent to participate in the study or who withdraw consent.
2. Individuals who are judged to have difficulty completing the baseline questionnaire. Individuals who have difficulty providing a saliva sample will be excluded from saliva collection and salivary DNA-based analyses but may participate in the "questionnaire only" arm.
3. Individuals for whom procedures necessary for assigning a study ID or linking annual data cannot be implemented.

Target sample size

8000

Name of lead principal investigator

1st name	Hiroyuki
Middle name
Last name	Toda

Organization

National Defense Medical College

Division name

Department of Psychiatry

Zip code

359-8513

Address

3-2 Namiki, Tokorozawa, Saitama, Japan

TEL

04-2995-1619

Email

psychiatry@ndmc.ac.jp

Name of contact person

1st name	Hiroyuki
Middle name
Last name	Toda

Organization

National Defense Medical College

Division name

Department of Psychiatry

Zip code

359-8513

Address

3-2 Namiki, Tokorozawa, Saitama, Japan

TEL

04-2995-1619

Homepage URL

https://www.ndmc.ac.jp/med/subject/sh_med036seishinkagaku/

Email

psychiatry@ndmc.ac.jp

Institute

National Defense Medical College

Institute

Department

Personal name

Hiroyuki Toda

Organization

National Defense Medical College

Organization

Division

Category of Funding Organization

Japanese Governmental office

Nationality of Funding Organization

Japan

Co-sponsor

Keio University; Shizuoka University

Name of secondary funder(s)

Organization

Ethics Committee, National Defense Medical College

Address

Secretariat of the Ethics Committee, Defense Medical Research Center, National Defense Medical College, 3-2 Namiki, Tokorozawa, Saitama 359-8513, Japan

Tel

04-2995-1211 ext 2604

Email

rinri@ndmc.ac.jp

Secondary IDs

NO

Study ID_1

Org. issuing International ID_1

Study ID_2

Org. issuing International ID_2

IND to MHLW

Institutions

防衛医科大学校（埼玉県）、海上自衛隊横須賀教育隊（神奈川県）

Date of disclosure of the study information

2026

Year

06

Month

10

Day

URL releasing protocol

Publication of results

Unpublished

URL related to results and publications

Number of participants that the trial has enrolled

Results

Results date posted

Results Delayed

Results Delay Reason

Date of the first journal publication of results

Baseline Characteristics

Participant flow

Adverse events

Outcome measures

Plan to share IPD

IPD will not be publicly shared. Pseudonymized study-ID data may be used only for approved collaborative analyses. Results will be reported only in aggregate.

IPD sharing Plan description

Individual participant-level data will not be publicly shared because this study handles sensitive information, including mental health, occupational, physical health, genomic, and epigenomic data. Pseudonymized analytic data using study IDs may be shared only with approved collaborating institutions to the extent necessary for collaborative analyses, in accordance with ethics approval, the study protocol, and data-sharing agreements. Study results will be published only as aggregate data from which individuals cannot be identified.

Recruitment status

Preinitiation

Date of protocol fixation

2026

Year

04

Month

30

Day

Date of IRB

2026

Year

05

Month

25

Day

Anticipated trial start date

2026

Year

07

Month

15

Day

Last follow-up date

2046

Year

12

Month

31

Day

Date of closure to data entry

Date trial data considered complete

Date analysis concluded

Other related information

This is a long-term prospective observational cohort study of new recruits of the Japan Maritime Self-Defense Force. Baseline questionnaire data will be collected, and saliva samples will be obtained from participants who consent to the "questionnaire plus saliva sample collection" option. Baseline psychological aptitude test data, annual mental health check-up data, and periodic health examination data will be linked using study IDs. No intervention will be conducted. The study will longitudinally examine associations of environmental factors, including adverse and protective childhood experiences and occupational stress, with PTSD-related symptoms, stress responses, addiction-related outcomes, suicide-related events, and physical health indicators. In selected analytic subsets of saliva-providing participants, biological indicators including genotype data, polygenic risk scores, and DNA methylation measures will also be integrated. In the UMIN registration form, the last follow-up date is entered as December 31, 2046, which is the latest selectable date at the time of registration; however, according to the study protocol, the planned total study period and long-term follow-up extend to March 31, 2066. Because of the long-term nature of this study, the protocol and registry information will be reviewed at least every 10 years, or when important revisions to relevant ethical guidelines or regulations occur, and will be updated as necessary.

Registered date

2026

Year

06

Month

01

Day

Last modified on

2026

Year

06

Month

01

Day

Link to view the page

Value
https://center6.umin.ac.jp/cgi-open-bin/ctr_e/ctr_view.cgi?recptno=R000070669