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Mental health screening
Picking up psychiatric problems
in primary care
BY Lena C. Quilty, PhD and R. Michael
Bagby, PhD
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For more than 25 years, primary care has been
recognized as the "de facto mental health services system" 1
within North America. This title reflects not only the high prevalence
of mental health disorders in primary care clinics, but also the
substantial proportion of mental health treatment conducted within
this setting. When examining the epidemiological evidence, it becomes
apparent that the assessment of mental health difficulties in general
practice is of great importance. Psychiatric disorders are frequently
characterized by both physical and mental symptoms, and primary
medical problems are often associated with psychologic complications.
Such mental health issues are underdiagnosed and undertreated in
primary care settings.
Indeed, as Edlund and colleagues2
point out, only half of patients presenting to their family physician
with a psychiatric disorder receive treatment, and less than half
of these people get counselling. Specialized mental health care
referrals don't appear to improve this state of affairs -- less
than a quarter of patients with a psychiatric disorder receive such
a referral, and even fewer follow through on it.
Such statistics clearly emphasize the necessity
of psychiatric diagnosis and treatment within primary care. In order
to meet this need effectively, however, practitioners require efficient
methods for the detection of psychiatric conditions. Considerable
research effort has been dedicated to the development of standardized
assessments for use in clinical research and practice, across a
variety of healthcare settings.
What's
the best way to screen?
As outlined by Bagby and colleagues,3
standardized assessment instruments provide a systematic and reliable
approach to the detection and diagnosis of mental health difficulties.
Such tools typically require the patient or clinician to indicate
agreement or disagreement with a series of statements. The responses
are summed and compared to empirically generated standards or norms
to determine where a patient ranks in comparison with others, ultimately
revealing the extent to which a particular symptom or condition
is present or absent. Examples of standardized assessment measures
commonly used in clinical research and practice include the Beck
Depression Inventory II and the Hamilton Rating Scale for
Depression.
Such standardized tools are a useful supplement
to clinical observation and judgement. They avoid the biases and
errors that can limit clinical decision-making, including the confirmatory
bias, i.e. a tendency to confirm existing beliefs or hypotheses;
the availability heuristic, a trend for decisions to be influenced
by the ease with which objects and events can be remembered; and
the base-rate fallacy, an inclination to recognize disorders that
receive disproportionate attention from the media. Clinical assessments
incorporating both clinical observation and standardized tests result
in consistent, thorough diagnoses.
What's
the best approach?
Noting that many clinical measures are cumbersome for routine
use in general medical settings, Staab and colleagues4 recommend
a two-step procedure, in which an initial standardized assessment
"screen" is followed by a more in-depth evaluation to confirm or
refute positive screening results. The initial screen incorporates
only a limited number of items and requires minimal resources. Still,
such tools have demonstrated acceptable sensitivity, i.e. the percentage
of patients accurately identified as exhibiting a disorder, and
specificity, i.e. the proportion of individuals accurately identified
as not having a specific condition. It's also been recognized that
"false positives" from brief screens -- patients incorrectly identified
as having a mental health problem -- often exhibit other psychiatric
concerns, or they may be just below the diagnostic threshold for
the disorder in question, and therefore require clinical attention.
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