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

a relationship with another person or group (relational) (Roberts & Roberts,
1999).

Are substance dependent people vulnerable persons?
Few studies have been conducted on whether persons who are substance
dependent have an impaired capacity to consent to participation in research
(Adler, 1995; Gorelick et al., 1999). Most of the recent controversy about
neuroscience research on vulnerable populations has been about research
on persons with schizophrenia (Shamoo, 1998) and stroke (Alves
&Macciocchi, 1996). In these cases, there are serious doubts about the
capacity of some patients to give free and informed consent because they
are cognitively impaired, either intermittently or chronically. There are some
analogies between these cases and issues concerning experimental research
on persons who are substance dependent. There are long-term neurological,
cognitive and psychiatric consequences of some types of substance use (see
Chapter 4), which may affect the ability of some individuals to give informed
consent.
Drug dependent persons may be vulnerable to coercion and inducement
to participate in research when they are intoxicated or when they are
experiencing acute withdrawal symptoms (Adler, 1995; Gorelick et al., 1999).
Persons who are severely intoxicated by alcohol and cocaine, for example,
suffer similar impairments to a person who is acutely psychotic. Similarly, a
person who is experiencing acute withdrawal symptoms could be induced
to consent to participate in research studies by offering them the substance
on which they are dependent, or medication to relieve their withdrawal
symptoms (Adler, 1995; Gorelick et al., 1999). Intoxicated persons should
normally be excluded from experimental studies on the grounds of good
research design, apart from the ethical problems associated with their
inclusion. Issues of informed consent arise in conducting controlled trials of
drugs that are used to treat symptoms of drug toxicity or overdose. In such
cases where a person is unable to give consent, proxy consent may be
required.

Provocation studies
Provocation studies in neuroscience research on dependence often use
neuroimaging to study the effects of a psychoactive substance on brain
function in substance users and substance dependent persons. For example,
persons dependent on heroin may be injected with a radioactively-labelled
substance, placed in a PET or SPECT scan (Fu & McGuire, 1999), and then
given an opioid drug or exposed to drug-related stimuli, with the aim of
identifying sites in the brain at which the drug acts (Sell et al., 1999; Kling et
al., 2000; Martin-Soelch et al., 2001). These provocation studies involve little
or no immediate prospect of therapeutic gain to participants. Their most likely

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