APPENDIX 12
Supplementary memorandum from the Advisory
Council on the Misuse of Drugs (ACMD)
ASSESSMENT OF
HARMFULNESS
1. The Council's advice on whether a substance
should be brought under the scope of the Act (ie "controlled"),
and into which class it should be placed, is based on three domains
of harmfulness. These are similar to those used by the Police
Foundations Independent Inquiry into the Misuse of Drugs Act.
2. These domains comprise:
— harms to individuals' physical and
mental health;
— dependence-producing potential; and
3. Harmfulness to physical and mental health
encompasses:
— acute (ie immediate or short-term)
toxicity including the consequences of overdose;
— chronic (ie long-term) toxicity particularly
after repeated use; and
3.1 The impact of a substance on physiological
functions, such as the control of respiration or blood pressure,
are major determinants of the acute toxicity of a substance.
3.2 Chronic toxicity generally relates to
the adverse effects of a substance following repeated exposure.
Adverse effects can, in some instances, occur at long intervals
of time after exposure.
3.3 Parenteral use poses two problems. First,
routes leading to very rapid absorption (especially intravenous
and inhalational administration) can have serious, and sometimes
lethal, consequences. Examples include respiratory arrest following
the administration of diamorphine and acute psychotic reactions
to inhaled methylamphetamine hydrochloride. Second, the injection
of substances carries the potential to transmit blood-borne infections
such as human immunodeficiency and hepatitic viruses.
4. The likelihood of dependence and addiction
relates to:
— the intensity of the pleasure derived
from use of a substance;
— the nature and intensity of psycholgical
withdrawal symptoms; and
— the nature and intensity of physical
withdrawal symptoms.
4.1 The pleasure that is derived from the
misuse of a substance has two components. The initial effect,
of rapid onset, is often called "the rush". The euphoria
that follows, and which can extend over several hours, is known
as "the high". The intensity of "the rush"
is, in part, related to the rate of entry of the substance into
the circulation and is particularly associated with the intravenous
or inhaled routes of administration (see paragraph 3.3 above).
4.2 Psychological dependence describes a
regular user's craving for a particular substance if denied access.
It may, or may not, be associated physical dependence.
4.3 Physical dependence describes non-psychological
symptoms and signs that may occur in regular users denied access
to a substance. Examples include tremors, sweating, insomnia and
increased heart rate.
5. The societal harmfulness is assessed
from:
— the consequences to the individual,
and to others, of acute intoxication;
— the risks of causing other social
harm; and
— the costs to the healthcare system
arising from the need of individuals, and others, to seek help.
5.1 Substance misuse may lead to inappropriate
behaviour by intoxicated individuals. This includes harms resulting
from an inability to concentrate (eg driving) as well as outbusts
of aggression. Drugs have also been used to coerce others to engage
in sexual activity ("date rape").
5.2 Substance misuse may have detrimental
effects on families including the neglect of children. Substance
misuse also leads to acquisitive crime.
5.3 Substance misuse also has significant
impact on the National Health Service as a consequence of the
services that have to be provided for dug users themselves, or
those they injure.
6. These three domains of harmfulness provide
a framework by which the Council can evaluated the risks associated
with particular substances. Professor David Nutt and his colleagues
have developed an assessment matrix which includes all nine parameters
of risk (Table 1).
Table 1
RISK ASSESSMENT MATRIX
| Category | Parameter
|
| Physical harm | Acute
Chronic
Parenteral
|
| |
| Dependence | Intensity of pleasure
Psychological dependence
Physical dependence
|
| |
| Social harms | Intoxication
Other social harms
Healthcare costs
|
| |
6.1 Using this matrix, and assigning a score to each
parameter (0 = no risk; 1 = some risk; 2 = moderate risk; 3 =
extreme risk), Professor Nutt and his colleagues have developed
an overall harm rating. They have not, as yet, attempted to weight
individual parameters.
February 2006
| 
