Happy Nurse Project: Lifestyle Interventions to Maintain Healthy Mental State in Hospital Nurses

The study is to explore the effectiveness of omega-3 fatty acids and mindfulness-based stress management program to maintain healthy mental state in hospital nurses. The participants will be junior nurses who work in inpatient wards and are not clinically depressed. The participants will be randomly allocated to four intervention arms: 1) Mindfulness-based stress management program plus omega-3 fatty acids pills ; 2) Mindfulness-based stress management program plus placebo pills; 3) Psychoeducation leaflet plus omega-3 fatty acids pills; and 4) Psychoeducation leaflet plus placebo pills. Thirty participants will be allocated to each arm. These interventions will terminate until three months from registration for each participant.

Information about depression and anxiety symptoms (primary outcome), insomnia, burnout, presenteeism, quality of life, sick leave, consultation about mental state of herself, and oxidative stress will be collected at 3 months, 6 months (primary time point) and 12 months from registration for each participant.

The study is to explore the effectiveness of omega-3 fatty acids and mindfulness-based stress management program to maintain healthy mental state in hospital nurses. The participants will be junior nurses who work in inpatient wards at four general hospitals in Tama region in Tokyo, and are not clinically depressed based on the score of the Hospital Anxiety and Depression scale. The participants will be randomly allocated to four intervention arms: 1) Mindfulness-based stress management program plus omega-3 fatty acids pills; 2) Mindfulness-based stress management program plus placebo pills; 3) Psychoeducation leaflet plus omega-3 fatty acids pills; and 4) Psychoeducation leaflet plus placebo pills. Thirty participants will be allocated to each arm. These interventions will terminate until 3 months from registration for each participant. Stress management program will be conducted by senior nurses in four individual sessions within these three months. Psychoeducation leaflet will include information about screening of stress, sleep hygiene, relaxation, and a list of consultants about mental health.

Information about depression and anxiety symptoms (primary outcome), insomnia, burnout, presenteeism, quality of life, numbers of incident and accident at work, sick leave and consultation about mental state of herself, concentration of fatty acids in serum and oxidative stress will be collected at 3 months, 6 months (primary time point) and 12 months from registration for each participant. The primary outcome will be assessed by blind raters through telephone.

The outcomes will be compared between arms including stress management program and those without, and between arms including omega-3 fatty acids and those without, by using mixed model repeated measures model.

Eligibility Criteria:
Inclusion Criteria:

* Work for inpatient wards in among four general hospitals in Tama region, Japan, including: National Center of Neurology and Psychiatry Hospital, National Disaster Medical Center, Tokyo Metropolitan Tama Medical Center, and Tama-Hokubu Medical Center
* Nurses without administration work
* Give written consent in the participation of the study

Exclusion Criteria:

* Have plans to take sick leave, leave for other reasons or retirement within 26 weeks from the entry to the study
* Take structured psychotherapy (e.g. cognitive behavioral therapy, interpersonal therapy, and brief psychodynamic therapy) at the entry
* See a physician regularly in order to treat any mood or anxiety disorders primarily at the entry
* Take antidepressants, mood stabilizers, anticonvulsants or antipsychotics at the entry
* Have taken nutrient supplement including omega-3 fatty acids for 4 or more weeks within 52 weeks from the entry
* Clinically depressed, based on the total score of 11 or more on the Hospital Anxiety and Depression Scale - Depression Subscale and the total score of 15 or more on the Primary Health Care Questionnaire
* Consume 4 times or more of fish as the main course of meal per week
* Take anticoagulant drugs at the entry or have previous history of stroke or myocardial infarction
* Judged ineligible by research coordinator due to any reason