Unit 3 – Health psychology: substance misuse

The use of animals in drug research

The specification requires that you are able to:• Describe and evaluate* the use of animals in

laboratory studies when researching into drugs

• Evaluate*, including relative strengths and weaknesses, research methods using animals (including both practical and ethical strengths and weaknesses)

Therefore the Learning Objectives for this session are that you will be able to:

• Describe how, and explain why animals are used in drug research

• Describe advantages of using animals for drug research (practical and/or ethical)

• Describe disadvantages of using animals for drug research (practical and/or ethical) Answer a past exam paper question on this topic and identify areas for improvement

Animal research on drugs...• Biological and medical research - this is concerned

with what keeps us (and animals) alive and healthy• For example – the brain; in relation to substance

misuse, this involves investigating the effects that various substances have on the brain

• This is important for our understanding of the mode of action of substances at the synaptic level, issues of tolerance, withdrawal and physical dependence and subsequently, for developing treatments for substance misuse

For example:• Rats were used to examine the effects of

chronic stress on ethanol (aka ethyl alcohol!) intake by Nagaraja & Jeganathan (2003)

• They found that the group of rats who were subjected to chronic stress (measured by overcrowding) increased their ethanol intake and ethanol preference over other liquids available, in comparison to the control group ( who were subjected to acute stress)

Another example:• Meisch (2001) used rhesus monkeys to investigate

whether drugs are reinforcing• The monkeys were given the opportunity to self-

administrate drugs* orally• *A range of drugs (opioids, stimulants and

ethanol) were used• Findings showed that drugs such as these are

reinforcing when taken orally; the monkeys chose to take the drugs as a reward – this links to the issue of addiction and substance misuse

• So, why use animals for drug research?• Basically, in order to do research which

couldn’t be conducted with humans for ethical reasons

• Cost is an issue also – it is cheaper to research with animals than humans (they are not as high maintenance!)

Issues to consider when using animals ...

• Ethical issues:o Causing pain and fearo Social isolationo Numbers of animalso Choice of species• Practical issues:o Similarities / differences between animals and

humanso Controlso Benefits for animals

Animal research – the 3 Rs …

• The people who work in laboratories with animals often get bad press; however, they have no interest in mistreating animals

• For many of them it is their primary responsibility to look after the animals, and they work with laboratory animals because they are animal lovers

• Many are also actively involved in developing scientific methods to reduce the need for animals or replace them entirely

Animal research – the 3 Rs …

• Good science and good animal welfare go hand in hand; if an animal is suffering stress or pain it could affect the results of the research

• Therefore, it makes good scientific sense to house animals in the best possible conditions and make sure they get the best possible care from skilled and experienced carers

• What animals need is not always the same as what people think they need, so scientists are studying which environments different animals prefer

Animal research – the 3 Rs …• Any researcher planning to use animals in their research

must first show why there is no alternative and what will be done to minimise numbers and suffering, ie:

• Replace the use of animals with alternative techniques, or avoid the use of animals altogether

• Reduce the number of animals used to a minimum, to obtain information from fewer animals or more information from the same number of animals

• Refine the way experiments are carried out, to make sure animals suffer as little as possible; this includes better housing and improvements to procedures which minimise pain and suffering and/or improve animal welfare

Evaluation – ethical issues …In the UK, the use of animals in laboratories is monitored and regulated by Home Office licence, so checks on their welfare are more likely than checks on the welfare of human participants!

If long-term negative effects of a drug manifest, it is considered that it is better that an animal suffers these than a human

Where studies cannot use human participants for ethical reasons, animals can be used because they are seen as expendable

Evaluation – ethical issues … It has been argued that current ethical guidelines do not do enough to protect laboratory animals from physical and psychological harm

Speciesism - ‘a prejudice or bias in favour of the interests of members of one's own species and against those of members of other species’; involves the judgment that being human is a good enough reason for human animals to have greater moral rights than non-human animals

Evaluation - practical issuesHigher levels of control are possible with animals than humans; animals have been specifically bred for research purposes and raised in controlled environments, so the effects of prior experiences can be controlled

Animal research is generally cheaper; amounts of substances needed are smaller and ensuring the welfare of animals is less expensive than ensuring the welfare of humans

Findings from animal research have highlighted the processes involved in addiction to substances at the synaptic level; this has then been investigated in humans under less rigorous conditions

Evaluation - practical issues• Extrapolation - can data from animal experiments

be unproblematically generalised to humans?• Yeah, but ….• Mammalian brains are similar in structure across

species• All mammals partake in major categories of

human behaviour: cognitive (memory, attention, perception), affective (emotional – fear, anger etc), motivational (aroused and directed behaviour – feeding, drinking, exploring)

Evaluation - practical issues

• No, but … • Animals are not necessarily good models for humans,

so results are not necessarily generalisable, because …• Different mammalian species have different genetic

and evolutionary histories, so they evolve in different ways and at different rates

• This links to an ethical issue – if findings cannot be generalised to humans, then the animals have suffered for no purpose

Evaluation - practical issues

• Also ...• Findings from animal research cannot be used to

explain the interaction between experiences, genetics and drugs which has been found in human drug use/misuse

• For example, it has been found that environmental cues can affect how people respond to drugs (how quickly they respond, intensity of response); it is extremely difficult to investigate this using animals (vastly different social environments and cues)