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Intern Health Study

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Read our disclaimer for details. Identifier: NCT01809080
Recruitment Status : Enrolling by invitation
First Posted : March 12, 2013
Last Update Posted : August 28, 2019
Information provided by (Responsible Party):
Srijan Sen, University of Michigan

Brief Summary:
Retrospective studies have established a strong correlation between reports of life stress and depression. Investigators have begun to further explore this relationship by examining the role of gene x stress interactions in the pathogenesis of depression. In a recent landmark study, Caspi and colleagues (2003) reported an interaction between a serotonin transporter promoter polymorphism and life stress in the development of depression. This finding has been replicated in some but not all follow up studies. Despite the initial promise of these results, the ability to draw definitive conclusions is compromised by significant study design limitations: 1) retrospective design 2) a focus on acute rather than chronic stress 3) substantial variation in the character and intensity of stress between subjects. Medical internship is a period filled with predictable and high levels of chronic uncontrolled stress. Rates of depression among interns are elevated compared to the general population. In this study, we aim to utilize the predictable and consistent stress of internship to investigate the relationship between stress, genes and depression with a prospective study design that bypasses some of the pitfalls of previous studies.

Condition or disease

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Study Type : Observational
Actual Enrollment : 4380 participants
Observational Model: Cohort
Time Perspective: Prospective
Official Title: Investigation Into the Interaction Between Genes and Stress in the Etiology of Depression in Interns
Study Start Date : May 2007
Estimated Primary Completion Date : July 2027
Estimated Study Completion Date : July 2027

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Primary Outcome Measures :
  1. Assess the change in rates of depression among medical interns. [ Time Frame: Months 0, 3, 6, and 12 of Intern Year ]
    The point prevalence of depression at various points through internship will be determined using subject responses to DSM-IV major depression items at the 0, 3-month, 6-month and 12-month assessments. To investigate whether there is a significant change in depressive symptoms through intern year, the investigators will compare PHQ (baseline) and PHQ (6 month) depression scores through a paired T-test. The effect of baseline psychological traits (neuroticism, resilience, personal history of depression, family history of depression, early family environment, social supports) on the development of depression will also be explored through linear regression analyses with each of the psychological factors as independent variables and PHQ (change) [PHQ (6 month) - PHQ (baseline)] as the dependent variable. The investigators will use linear regression to investigate correlations between training program characteristics (average work hours, specialty) and PHQ (change).

Secondary Outcome Measures :
  1. Evaluate the presence of genotype x stress interaction among this sample. [ Time Frame: Sample within first 6 months of Intern Year (Because DNA sequence generally does not change with time, the exact timing of sample collection is not critical to the analysis) ]
    As a baseline analysis, the investigators will investigate association between each variant/haplotype and PHQ (baseline) scores using linear regression. To explore gene x environment interactions, the investigators will assess for association between each variant/haplotype and PHQ change scores (Mean (3,6,9 and 12 month PHQ score) - Baseline (PHQ score)).

  2. Evaluate the relationship between serum factors and changes in depressive symptoms under stress. [ Time Frame: Months 0 and 10 of Intern Year ]
    For each of the proteins assessed (IL-1beta, IL-6, IL-10, hs-CRP and TNF-alpha), Pearson correlation will be used to assess the relationship between serum and saliva levels. The investigators will assess whether there is a significant change in the serum levels of endothelial and inflammatory markers and endothelial function using a within-subject paired T-test, with baseline values (low stress) paired with internship stress values (high stress). To assess whether the change in endothelial and inflammatory markers correlate with a change in depressive symptoms, the investigators will utilize a linear regression, with the change in marker level used as explanatory variables and the change in depressive symptoms score (PHQ (change) = mean residency depressive symptoms - baseline depressive symptoms) used as the outcome variable

  3. Examine the temporal relationship between hair cortisol level changes, stress exposure and changes in depressive symptoms [ Time Frame: Months 0, 4, 8, 12 of Intern Year ]
    Statistical analysis will be conducted using Generalized Estimating Equation (GEE) analysis. To assess whether there is a change in hair cortisol indices with internship stress, the investigators will perform a paired T-test, with pre-internship factor cortisol level paired with post-internship factor cortisol level. To determine the relationship between hair-related factors (hair color, hair treatment, washing frequency), transient mediating factors (work hours, outside stressful life events, recent exercise, sleep and illness), long-term mediating factors (BMI, regular exercise schedule, smoking behavior) and long-term cortisol, the investigators will assess whether the difference in level of these factors between the two assessments shows a significant correlation with the difference in cortisol level. Next, the investigators will identify whether that change in hair cortisol is associated with the change in depressive symptoms while accounting for related variables.

Biospecimen Retention:   Samples With DNA

Saliva: DNA collection kits are sent via postal mail and participants are asked to provide a small sample of saliva.

Blood samples (up to 50 mL via venopuncture): whole blood and serum will be assessed.

Hair: The total diameter taken from the scalp's posterior vertex will be about 3 mm, which is about half of the diameter of pencil (approximately 100 hair strands with a minimum of 50 mg of hair for a 3-cm segment).

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Ages Eligible for Study:   Child, Adult, Older Adult
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   Yes
Sampling Method:   Non-Probability Sample
Study Population
Medical internship is an attractive model to bypass some limitations of previous studies. Internship is well chronicled as a time of high stress (Butterfield 1988; Addison et al 2004). Interns are faced with long work hours, sleep deprivation, loss of autonomy and extreme emotional situations (Shanafelt & Habermann 2002). Many physicians recall internship as among the most stressful years of their lives (Duffy 2005). The stress of internship is often uncontrollable, unpredictable and chronic; features that are particularly linked to the development of depression (Kendler et al 2003; Cryan et al 2004). Several studies have estimated the point prevalence of depression among interns at 28%-37% (Valko & Clayton 1975; Reuben 1985; Cohen et al 2006), in contrast to a point prevalence of 5% in general population (Murphy et al 2000). There is also evidence that physicians have underlying personality traits that predispose to depression (McDonough 1990; Hojat et al 1999).

Inclusion Criteria:

  • Subjects for our study will be drawn from incoming interns in the traditional and primary care internal medicine, general surgery, pediatrics, obstetrics/gynecology, neurology and psychiatry residency programs at participating University and Community residency programs, as well as fourth year medical students at participating medical schools.

Exclusion Criteria:

  • None.

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its identifier (NCT number): NCT01809080

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United States, Michigan
University of Michigan Medical School
Ann Arbor, Michigan, United States, 48109
Sponsors and Collaborators
University of Michigan
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Principal Investigator: Srijan Sen, MD, PhD University of Michigan
Publications of Results:
Other Publications:
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Responsible Party: Srijan Sen, Assistant Professor of Psychiatry, Medicial School, University of Michigan Identifier: NCT01809080    
Other Study ID Numbers: MH-095109
First Posted: March 12, 2013    Key Record Dates
Last Update Posted: August 28, 2019
Last Verified: August 2019
Additional relevant MeSH terms:
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Behavioral Symptoms