New Physicians at Increased Risk for Depression During Internship

Pam Harrison

April 07, 2010

April 7, 2010 — The percentage of new clinicians who develop depressive symptoms increases significantly during medical internship, new research suggests.

A large prospective study showed a marked increase in depressive symptoms among new clinicians — from 3.9% at baseline to an average of 25.7% (P < .001) during internship — as reflected by increases in the 9-item Patient Health Questionnaire (PHQ-9).

Srijan Sen, MD, PhD, University of Michigan, Ann Arbor, and colleagues also found that 41.8% of participants met criteria for major depression at one or more quarterly assessments.

On stepwise linear regression analysis, neuroticism (P < .001), personal history of depression (P < .001), lower baseline depressive symptoms (P < .001), female sex (P = .03), US medical education (P = .005), and a difficult early family environment (P = .04) significantly correlated with a change in depressive symptoms.

"When myself and coinvestigator Constance Guille were interns 4 years ago, we noticed that people who were well adjusted and happy a few months before were having trouble sleeping and problems with their relationships and just struggling to adjust, so it struck us that these problems were very common during internship," Dr. Sen told Medscape Psychiatry.

"And while I think internship will always be a stressful time, there are things that we may be able to do to make it better for interns, including working fewer hours and using electronic records to reduce the risk of errors and making sure interns have some resources in place before they become depressed to reduce the effects of stress," he added.

The study was published online April 5 in the Archives of General Psychiatry.

No Link to Medical Specialty or Age

For the study, investigators recruited a total 1271 interns entering traditional and primary care internal medicine, general surgery, pediatrics, obstetrics-gynecology, and psychiatry residency programs during the 2007-2008 and 2008-2009 academic years. Depressive symptoms were measured using the depression module of the PHQ-9, where the total score ranges from 0 to 27. The PHQ-9 scores of 10 to 14 correspond to moderate depression, scores between 15 and 19 to moderately severe depression, and scores of 20 or greater to severe depression.

Mean PHQ-9 scores increased significantly from 2.38 at baseline to 6.70 at 3 months, 6.48 at 9 months, and 6.26 at 12 months (all P < .001 vs baseline). The percentage of subjects meeting criteria for moderately severe depression increased from 0.7% at baseline to 6.6%, 6.2%, 7.8%, and 7.6% at 3-, 6-, 9-, and 12-month points of the internship, respectively, the investigators add.

Similarly, the percentage of interns who met criteria for severe depression increased from 0% at baseline to 2.3%, 1.6%, 1.8%, and 0.8% at 3, 6, 9, and 12 months of internship, respectively. Investigators also assessed factors during internship that were associated with a change in depressive symptoms.

The 3 key variables that were associated with a significant increase in the risk for depressive symptoms were work hours (P < .001), reported medical errors (P < .001), and noninternship stressful life events (P < .001).

Interestingly, medical specialty and age were not associated with the development of depression.

5-HTTLPR Moderates Stress and Depression Response

Investigators also used internship as a model to explore the relationship between a serotonin transporter promoter polymorphism and stress in the development of depression.

"We found evidence that this variant moderates the response to stress in European American subjects, with subjects carrying at least one low-functioning 5-HTTLPR allele reporting a 43% greater increase in depressive symptoms than subjects with two low-functioning alleles," the study authors write.

European American participants with 2 high-functioning 5-HTTLPR alleles who met criteria for depression increased from 5.1% before internship to 36.2% at its highest during internship. Investigators also found that the association between 5-HTTLPR and the development of depressive symptoms under stress was moderated by neuroticism and work hours, although not with medical errors or stressful life events.

"Medical internship provided us with the unique situation where we know that a group of people currently under low stress will enter a period of high stress, and we showed that 5-HTTLPR had no effect on depression under the low stress conditions but was strongly associated with depression under high stress," Dr. Sen told Medscape Psychiatry. "So in my view, this provides strong evidence that 5-HTTLPR moderates the relationship between stress and depression, [although] the effect of this one genetic variant is relatively small compared with other factors, such as work hours, gender, and prior history of depression."

Stressful Experience

Gregory Dalack, MD, University of Michigan, Ann Arbor, agreed that internship is clearly a stressful experience, "as all of us who went through it know."

"Nevertheless," he said, "depressive symptoms detected in this cohort of interns were self-reported, which is different than detecting symptoms with a clinical diagnosis, because with a clinical diagnosis, physicians can rule out ongoing substance abuse problems or other medical conditions that may be contributing to symptoms such as sleep disturbances, which on self-reported questionnaires may be mistakenly attributed to depression."

Dr. Dalack also noted that a number of organizations have already put forward suggestions that are intended to reduce stress among interns, including limitations of hours worked. Currently, interns are still allowed to work 80 hours per week.

"They are following these recommendations prospectively to make sure hospitals are putting systems in place so that residents are not overworked, and while there may be transgressions from the rules under some circumstances, there is a higher level of scrutiny now in place to make sure people stay within those limits so as to reduce interns’ fatigue and depression and maintain a high level of quality care for patients," he said.

The study was supported by a Donaghue Foundation Clinical and Community Grant, an American Psychiatric Association Substance Abuse and Mental Health Services Administration grant, a Veterans Administration Research Enhancement Award Program award, and an American Foundation for Suicide Prevention Young Investigator grant.

Arch Gen Psychiatry. Published online April 5, 2010.


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