A prospective cohort study investigating factors associated with depression during medical internship.
BACKGROUND
Although the prevalence of depression among medical interns substantially exceeds that of the general population, the specific factors responsible are not well understood. Recent reports of a moderating effect of a genetic polymorphism (5-HTTLPR) in the serotonin transporter protein gene on the likelihood that life stress will precipitate depression may help to understand the development of mood symptoms in medical interns.


OBJECTIVE
To identify psychological, demographic, and residency program factors that are associated with depression among interns and to use medical internship as a model to study the moderating effects of this polymorphism.


METHODS
A prospective cohort study.


METHODS
Thirteen US hospitals.


METHODS
Seven hundred forty interns entering participating residency programs.


METHODS
Subjects were assessed for depressive symptoms using the 9-item Patient Health Questionnaire (PHQ-9), a series of psychological traits, and the 5-HTTLPR genotype prior to internship and then assessed for depressive symptoms and potential stressors at 3-month intervals during internship.


RESULTS
The PHQ-9 depression score increased from 2.4 prior to internship to a mean of 6.4 during internship (P < .001). The proportion of participants who met PHQ-9 criteria for depression increased from 3.9% prior to internship to a mean of 25.7% during internship (P < .001). A series of factors measured prior to internship (female sex, US medical education, difficult early family environment, history of major depression, lower baseline depressive symptom score, and higher neuroticism) and during internship (increased work hours, perceived medical errors, and stressful life events) was associated with a greater increase in depressive symptoms during internship. In addition, subjects with at least 1 copy of a less-transcribed 5-HTTLPR allele reported a greater increase in depressive symptoms under the stress of internship (P = .002).


CONCLUSIONS
There is a marked increase in depressive symptoms during medical internship. Specific individual, internship, and genetic factors are associated with the increase in depressive symptoms.
Sen
Srijan
S
Department of Psychiatry, University of Michigan, Ann Arbor, MI 48109, USA. srijan@umich.edu
Kranzler
Henry R
HR
Krystal
John H
JH
Speller
Heather
H
Chan
Grace
G
Gelernter
Joel
J
Guille
Constance
C
D000328:Adult; D015331:Cohort Studies; D003863:Depression / Q000175:diagnosis / Q000453:epidemiology / Q000235:genetics; D003866:Depressive Disorder / Q000453:epidemiology* / Q000235:genetics*; D003865:Major Depressive Disorder / Q000453:epidemiology / Q000235:genetics; D005260:Female; D005838:Genotype; D006304:Health Status; D006801:Humans; D007396:Internship and Residency / Q000706:statistics & numerical data*; D008016:Life Change Events; D008297:Male; D008511:Medicine; D020641:Polymorphism, Single Nucleotide / Q000235:genetics; D015995:Prevalence; D011446:Prospective Studies; D012307:Risk Factors; D050486:Serotonin Plasma Membrane Transport Proteins / Q000235:genetics; D013315:Stress, Psychological / Q000235:genetics / Q000523:psychology; D013337:Students, Medical / Q000523:psychology* / Q000706:statistics & numerical data; D011795:Surveys and Questionnaires
C493230:SLC6A4 protein, human; D050486:Serotonin Plasma Membrane Transport Proteins