The use of electroconvulsive therapy in Quebec - INESSS

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and pharmacotherapy seem to be more effective than
pharmacotherapy or psychotherapy alone [Geddes
et Butler, 2001]. Cognitive therapy also appears to be
as effective as pharmacotherapy for outpatient treatment
of patients suffering from severe major depression
[DeRubeis et al., 1999].
When a rapid therapeutic effect is sought or
when the patient is suffering a great deal or represents
a suicide risk, or if he refuses to eat or drink,
several clinicians use ECT as a treatment of first
choice. Generally, ECT is used in cases of pharmacotherapy
and psychotherapy resistance. However,
there do not appear to be any criteria defining psychotherapy
resistance. The concept of pharmacotherapytreatment
resistance was defined for the first time in
1974 as the failure to respond to a standard antidepressant-treatment
trial equivalent to 150 mg of
imipramine for a period of at least three weeks
[Wilhelm et al., 1994]. Recent definitions of antidepressant
resistance provide for a period of at least six
weeks in which to evaluate treatment response,
including serum dosages of the antidepressant used
[Berman et al., 1997; Fava and Davidson, 1996;
Thase and Rush, 1995]. In addition, in an adequate
trial, standard antidepressant resistance is defined as
first-degree resistance, and one of the grading
systems for pharmacology-treatment resistance
proposes five resistance levels, the last corresponding
to ECT resistance [Thase and Rush, 1995].
Few epidemiological data exist concerning
pharmacology-treatment resistance. In practice, the
diagnosis of treatment resistance seems to be based
on the result of the diagnostic and therapeutic process
rather than on patient-specific characteristics [Guscott
and Grof, 1991]. For example, in a study on depression-treatment
practices in Finland, 71% of tricyclicantidepressant
prescriptions consisted of doses
generally considered ineffective [Isometsa et al.,
THE USE OF ELECTROCONVULSIVE THERAPY IN QUÉBEC
1998]. In a Canadian study of 114 patients referred
to a tertiary centre with a diagnosis of treatmentresistant
depression, 38 responded to standard treatments
with an adequate trial of a tricyclic
antidepressant, a monoamine oxidase inhibitor or
ECT, and 21 others responded to other types of pharmacotherapy
[Remick, 1989]. In a study on the
sequential treatment of depression in 101 geriatric
patients, 94.4% of the patients responded to the various
levels of treatment. ECT was used for the last level
in four patients, with only one patient responding to
the treatment [Flint and Rifat, 1996].
The relative decrease in ECT efficacy in populations
manifesting a certain degree of pharmacotherapy
resistance is a known fact. According to the
American Psychiatric Association practice guidelines,
the ECT response rates are in the order of 80% to 90%
when ECT is used as a first-line treatment and in the
order of 50% to 60% when ECT is used after one or
more adequate trials with antidepressant medications
have failed [American Psychiatric Association and
Task Force on Electroconvulsive Therapy, 2001, p. 10].
It is important to note that treatment response is often
defined as at least a 60% decrease on the Hamilton
scale, measured immediately after the end of the treatment
course. Thus, the response is not necessarily
sustained. In one of the rare high-quality studies measuring
ECT efficacy in relation to pharmacotherapy
resistance [Prudic et al., 1996], 32 of 35 non-resistant
patients (91.4%) responded to ECT immediately after
the course of treatment ended. One week later, only 26
of the 35 patients (74.3%) were in this category. For
the pharmacotherapy-resistant patients, 41 of the 65
patients (63.1%) responded favorably, immediately
after the course of treatments ended. One week later,
31 of the 65 patients (47.7%) were in this category.
These figures highlight the importance of an attentive
examination of the types of efficacy indicators used in