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7. ETHICAL ISSUES IN NEUROSCIENCE RESEARCH ON SUBSTANCE DEPENDENCE TREATMENT AND PREVENTION

representation of those who are treated by private health services or private
specialist physicians and psychiatrists. It is also possible that the results of a
study may potentially lead to stigmatization of a group, if for example, a study
identifies a high rate of substance dependence in a particular social, cultural
or ethnic group.

Ethical issues in clinical trials of pharmacological treatments
for substance dependence
Clinical trials of new therapeutic drugs are required for drug registration in
most developed countries and are a now widely accepted part of medical
practice. There is international agreement on the criteria for the ethical
conduct of such studies. In addition to the previously discussed issues of
independent ethical review – i.e. free and informed consent by study
participants; an acceptable risk–benefit ratio for participants; and protection
of patient privacy and confidentiality (Brody, 1998) – there are also issues of
trial design, conflict of interest and distributive justice.

Trial design
A randomized controlled trial is widely accepted as the “gold standard” for
treatment evaluation in medicine because it minimizes bias in determining
which patients receive which treatments (Cochrane, 1972). Random
assignment to treatment is ethically acceptable if there is genuine uncertainty
about the comparative worth of the two treatments; if trial participants are
aware that they will be randomized; and if they are informed about the type
of treatment to which they may be assigned (e.g. active or placebo), and the
risks of these treatments in the course of obtaining their informed consent
to participate in the trial.
The choice of a comparison condition for a randomized controlled trial raises
the issue of when is it ethically acceptable to compare the effectiveness of a
new drug treatment for substance dependence with a placebo. Some authors
have argued that it is unethical to provide only a placebo treatment, if there is
an existing treatment that is effective for the condition (Brody, 1998). This
argument is relevant in the case of substance dependence, some forms of which
can be life-threatening in the absence of treatment. It would be ethically
acceptable, however, to use a placebo comparison condition if there was no
effective pharmacotherapy for the condition, and if both treatment groups
received the best available psychosocial treatment (Gorelick et al., 1999). In
this case, the clinical trial would answer the question: does adding
pharmacotherapy to good quality psychosocial care improve outcome by
comparison with adding a placebo? Since it is likely that any pharmacotherapy
will ultimately be used in combination with good quality psychosocial
treatment (Fox, 1997), this is usually the most relevant question to ask in a
randomized controlled trial of a new pharmacotherapy for drug dependence.

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