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8. CONCLUSION AND IMPLICATIONS FOR HEALTH POLICY

CHAPTER 8

Conclusion and Implications for Public

Health Policy

Introduction
There is now a much better understanding of the mechanisms of action of
different psychoactive substances in the brain, and of why people experience
pleasure or the relief of pain from using the substances. Substances differ
with respect to the particular class of receptors they affect in the brain, but
there are also considerable commonalities between them. The neural
pathways that psychoactive substances affect are also those which are affected
by many other human behaviours, including eating a meal, having sex, and
gambling for money. In this sense, the use of psychoactive substances, at
least initially, is one part of the spectrum of human behaviours which
potentially bring pleasure or avoid pain. Depending on the route of
administration, the substances may have an especially intense effect and high
concentrations of some of them are lethal.

Advances in the neuroscience of psychoactive substance use
and dependence and their implications
Psychoactive substances also differ in their non-neural biological effects. The
form and means of administration of the substance are important in this
dimension. Thus the potential for adverse health effects from nicotine taken
in as cigarette smoke is high compared with that from nicotine in chewing
gum. There is thus a strong public health interest in differentiating the
availability of different forms of the substance according to their adverse
health effects.
Apart from their toxic biological effects, there are two other mechanisms
by which psychoactive substances may have adverse health and social effects,
as outlined in Chapter 1 (Fig. 1.2). One is through their psychoactive effects,
and particularly through intoxication. Different psychoactive substances
differ in the nature and severity of their intoxicating effects. Those of alcohol,
for instance, are great, and the potential for adverse casualty consequences
accordingly large, while the effects of nicotine as usually consumed are small.
Limiting the harm from intoxication, not only to the substance user but also
to others, is an important objective for public health-oriented controls of
the use of psychoactive substances.

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