Biomedical Engineering Reference
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return of the symptoms themselves (e.g., psychotic symptoms such as hallucinations
or delusion). As a patient of one of the authors (IAC) liked to frame the question for
her recurrent depressions, “When is a bad day just a 'bad day,' and when is it the
start of a new episode?” In the care of older adults with depression, some will likely
progress from late-life depression to dementia [68], but identification of this subset
of patients remains problematic.
Lastly, many patients with mood disorders experience recurrent thoughts of
death and may perceive life as painful and/or meaningless while in the midst of a
depressive episode. Although this group of patients has an elevated risk for suicidal
behaviors, accurately determining which individuals will go on to harm themselves
and which will not cannot be forecast reliably on clinical or historical grounds [69];
some preliminary work suggests measures of brain structure and function [70, 71]
or genotyping [72, 73] may be developed to refine this process. Rather than believ-
ing that research efforts will eventually identify
the
single, measurable factor that
leads to a phenomenon as complex as suicide, it may be more reasonable to antici-
pate that the greatest clinical utility for this sort of prediction may emerge from a
model combining genetic and neurobiological features with current and past clini-
cal features and familial history, though the relative weightings of these factors
remains indeterminate at this time.
Prediction of individual treatment response is viewed by many as a critical area
for improvement in psychiatry. Whereas treatments are effective for managing psy-
chiatric illnesses in general, no single treatment works for everyone with a given dis-
order, and selection of the best treatment for each patient remains a challenge. The
general standard of care is to embark on a course of treatment that is likely to be
effective for that disorder, based on evidence from randomized clinical trials and
other data relevant to the individual patient (e.g., clinical experience, past patient
response to treatment); one then monitors for a good outcome and allows for treat-
ment adjustment if improvement fails to occur. Both steps fundamentally rely on
clinical findings to assess the degree of symptomatic or functional response. Nobel
laureate Niels Bohr often is said to have observed that “Prediction is difficult, espe-
cially about the future,” and this statement rings true in this aspect of psychiatric
care. The failure of depressive symptoms to improve early in treatment often her-
alds poor eventual outcome [74], but what is true on a group level does not neces-
sarily provide useful guidance on a patient-by-patient basis; for instance, some
patients simply may take longer than others to respond to treatment that eventually
will work well for them [75].
Measurement-based care [76, 77], with its systematic collection of clinical data
with rating scales, can improve detection of good or poor response to treatment
with greater utility than a clinician's global impression, but fundamentally these are
better observations of what is already occurring, rather than predictions of future
outcomes. The principle of identifying “the right drug for the right person at the
right dose at the right time (phase of illness)” is central to the “personalized medi-
cine” approach [78]. Not inconsequentially, this runs contrary to the “blockbuster
medication” school of thought, predicated on the belief that a compound can be
developed that will be an effective treatment for nearly all patients with a particular
disorder and thus take preeminence in practice and in the marketplace.
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