Psychiatrists and critical care specialists at Johns
Hopkins have begun to tease out what there
is about a stay in an intensive care unit that leads so
many patients to report depression after they go
In a study reported online April 10 in Critical
Care Medicine, the researchers say that several
factors predicted symptoms of depression six months after
hospitalization among very sick ICU
patients, including a high level of organ failure and being
given relatively high doses of a
"The hope is that as we learn more about the effect of
variations in ICU care, we'll be able to
predict which patients are most susceptible to depression,
prevent some depression by changing ICU
practices and make sure patients receive adequate mental
health monitoring after discharge," said O.
Joseph Bienvenu, an associate professor in the
Department of Psychiatry at the Johns Hopkins
University School of Medicine.
Bienvenu says that doctors have long theorized that a
health problem devastating enough to
send someone to an ICU might well trigger depression, but
because only some patients become
depressed, he and his colleagues wondered whether the root
causes might be more complex.
"Historically, the only goal for critical care
physicians, understandably, was to keep people alive,
but now there is interest in longer-term outcomes, such as
patients' mental health and well-being,"
Bienvenu said. "So we asked ourselves, Could certain
aspects of critical illness and ICU care swing
patients toward depression?"
To test the idea, Bienvenu and other Johns Hopkins
researchers evaluated patients recently
admitted to one of 13 ICUs located at four teaching
hospitals in Baltimore, including four ICUs at The
Johns Hopkins Hospital.
Each of the patients was treated for acute lung
injury, or ALI, a respiratory distress syndrome
that's considered an archetype of critical illness.
Patients with ALI typically require invasive
interventions in the ICU, including use of ventilators.
Though better care has greatly reduced
mortality rates, ALI still kills about 40 percent of those
Bienvenu and his colleagues followed 160 patients who
had survived at least six months after
their ALI diagnosis. The researchers took note of a variety
of features of each patient's status and
care while in the ICU, such as severity of organ failure,
blood sugar levels and other lab work, and the
amount and type of sedative received.
At six months after ALI diagnosis, the researchers
administered to patients a questionnaire
that measured depressive symptoms ranging from none to
possible or probable clinical depression. Of
the 160 patients, 26 percent scored above the threshold for
possible depression. Compared to other
ALI survivors, the depressed patients were more likely to
have suffered greater severity of organ
failure and to have received 75 mg or more of a
benzodiazepine sedative daily.
Bienvenu says that because more severe organ failure
may lead to a longer physical recovery
period after ICU discharge, patients' depression may be
explained in part by a slow recovery.
However, he says that he and his colleagues aren't
sure how to explain the association between
depression and benzodiazepine dose. One possibility could
be that the amount of this drug received
reflects how agitated patients were in the ICU, with very
distressed individuals getting higher doses.
However, because this relationship hasn't been seen with
other types of sedatives commonly
prescribed in the ICU, it's possible that high doses of
benzodiazepine alone may somehow cause
depressive symptoms. "This is clearly a question that needs
further study," Bienvenu said.
Other Johns Hopkins researchers who participated in
this study are David W. Dowdy (now at
the University of California, San Francisco), Victor D.
Dinglas, Pedro A. Mendez-Tellez, Jonathan
Sevransky, Carl Shanholtz and Dale M. Needham.