8.2.2 human drug studies Flashcards
what is a randomised control trial?
in health psychology
Used to look at the effectiveness of therapy
One group has the therapy and the control group does not. They are equal in terms of characteristics
Pps are randomly allocated to the treatment group or the control group
human drug studies - what methods can we use?
- Randomised Control Trials
- PET scanning
what is a placebo?
A substance or a treatment that is not the actual treatment being measured, but seems to be the treatment; the ppt. cannot tell the difference.
what is a placebo controlled trial?
- Definition: one group gets the treatment and the other gets a placebo treatment.
- Eg. The placebo group will get a sugar pill, while the treatment group gets an antidepressant, such as Prozac.
- The pps. won’t be told which group they are in (Single Blind) - why?
- Sometimes, the researchers won’t know either (Double Blind) - why?
how did pengpid use a randomised controlled trial?
Used a randomised controlled trial with six and twelve-month follow-ups to look at the effectiveness of a brief intervention looking at alcohol consumption in South Africa
randomised controlled trial - strengths
- Validity: If the two groups are statistically equal and everything else is controlled apart from the IV (two groups- treatment or control), then valid-cause-and-effect conclusions can be drawn because the effectiveness of the treatment group can be compared to the control group. Support with Pengpid: What were the two groups? How were pps similar?
- Validity: Using single and double-blind techniques can help avoid the placebo effect and reduce the chance of researcher bias, demand characteristics which improves validity. Support with Pengpid: Describe how a single-blind procedure was used.
randomised controlled trial - weakness
- Unethical: The treatment group gets the treatment which they may benefit from, but the control group is deprived of the treatment so doesn’t benefit, this is unethical.This can be overcome by placing the control group on a waiting list so they get the treatment at the end of the trial.
- Support with Pengpid: What did the control group miss out on?
- Validity: Pps can improve just by being on what they perceive to be a treatment program no matter what the treatment is or even if they are on a waiting list - this is the placebo effect, this lowers the accuracy of measuring how effective the treatment is compared to the control/waiting list.
- Support with Pengpid: how did the procedure provide a form of intervention even for the control group, which may have helped them to improve their drinking habits?
human drug studies - pet scan
how does it work and how are they useful?
Because drugs affect the brain, scanning can be useful to get a picture of what happens when drugs are taken.
PET scanning involves a radioactive tracer that is injected into the body, which is added to a glucose solution. The solution gets used up in the parts of the brain where there is activity. The tracer breaks down and produces positively charged positrons. The scanner picks up ‘hot spots’ of brain activity which show up as red and orange.
what is an example of a Health Study which uses PET scans?
Scott et al (2004)
scott et al - procedure
- This study used PET scanning on humans to show that smoking cigarettes stimulates the brain to produce opioids, which act in the brain to increase positive emotions and relieve pain symptoms. Morphine and heroin also affect the brain in the same way.
- The researchers studied the opioid system in the brain - PET scans are detailed enough and are able to show opioid receptor activity.
- Six healthy male pps. stopped smoking for at least 10 hours before the study began and, during the scan, they each smoked first a cigarette with practically no nicotine and then a ‘normal’ cigarette.
- The researchers also asked the men how they were feeling at certain times during the study.
scott et al - findings and conclusion
- The scan picked up significant differences in opioid flow when the pp smoked the low-nicotine cigarette compared to the normal one.
- There was increased opioid activity when the men smoked the normal cigarette. The scans also showed that after the normal cigarette, the men had fewer cravings and it was noted from the scan that the brain regions for memory, emotion and pleasure were less active. The men reported feeling more relaxed and less alert, which matches the scan findings.
- The same activity was not found in the low-nicotine cigarettes.
- The findings suggest that nicotine binds to the opioid receptors just as morphine and heroin do.
evaluation of pet scans
in health psychology
Reliability: standardised procedure using scanning equipment which produces objective pictures of brain activity, which can be easily repeated and checked by more than one researcher to achieve inter-rater reliability.
SUPPORT W/ SCOTT - All stopped smoking for at least 10 hours before the study began and, during the scan, they each smoked first a cigarette with practically no nicotine and then a ‘normal’ cigarette.
Valid: produces accurate, objective images of brain activity, which enables researchers to see which parts of the brain are active during certain activities/behaviours.
SUPPORT W/SCOTT - Found there was increased opioid activity when the men smoked the normal cigarette. The scans also showed that after the normal cigarette, the men had fewer cravings and it was noted from the scan that the brain regions for memory, emotion and pleasure were less active. The men reported feeling more relaxed and less alert, which matches the scan findings.
evaluation of pet scans
in health psychology
Ethics: being injected with a radioactive substance can be distressing and it is invasive, although the small amount of tracer is not harmful.
SUPPORT W/ SCOTT - Six healthy male pps. stopped smoking for at least 10 hours before the study began, they were injetced with a radioactive tracer
Valid: although brain activity can be seen clearly, it produces broad images of colour so detail may be unclear. It may be hard to distinguish between warm and cold colours, therefore lowering accuracy.
SUPPORT W/ SCOTT - scans showed that after the normal cigarette, the men had fewer cravings and it was noted from the scan that the brain regions for memory, emotion and pleasure were less active - MAY HAVE BEEN MISINTERPRETED OR UNCLEAR
