1. Health research Assist. Prof. Merve Topcu PSY 411 Health Psychology Department of Psychology Çankaya University 2016-2017, Fall 1

2. Health research People rely more on personal experience rather than research findings – Placebo effect & nocebo effect Placebo: an inactive substance or condition with appereance of an active treatment Effect due to expectation rather than effects of the treatment Operant & classical conditioning – Response to ‘procedures’ 2

3. So what? Need to know whether it is due to treatment effect or it is simply due to belief – E.g., up to 80% of the effectiveness of antidepressants is due to placebo effect – E.g., affects medication’s potency Seeing larger, colored, capsulated, and brand-named pills more effective than smaller and generic ones E.g., hypnosis, acupuncture, biofeedback, relaxation training, massage, counselling, etc. To be able to say ‘effective’, it must show a higher rate of effectiveness than that produced by a placebo. 3

4. Research & Placebo effect Control groupped designs – Control for group expectations Double-blind design – Participants & experimenters do not know which group has intervention or placebo Single-blind design – Only participants do not know 4

5. What is the source of health information? Use research methods – Correlational Study – Cross-sectional Studies – Longitudinal Studies – Experimental Desings – Ex Post Facto Desings 5

6. What is the source of health information? Use research methods – Correlational Study Degree of r/ship btw two variables Descriptive research design No causal r/ship! Correlational coefficients (from -1 to +1) Help to determine risk & proctective factors – E.g., smoking, systolic blood pressure, and waist circumsference are risk factors for cardiovascular diseases Risk factor: any characteristic or condition that occurs w/ greater frequency in people w/ a disease than in people free from that disease 6

7. What is the source of health information? Use research methods – Cross-sectional Studies Used especially in developmental issues Time-saving Conducting study during only one point in time Choose a group of people at least two different age groups – E.g., compare 30-year-old participants with 60-year-old participants in terms of blockage of coronary arteries No causality! 7

8. What is the source of health information? Use research methods – Longitudinal Studies Used especially in developmental issues Follow participants over an entended period of time Assess individuals over time Identify developmental trends & patterns Disavd: takes time & costly No causality! 8

9. What is the source of health information? Use research methods – Experimental Desings Causality – One variable to cause or directly influence another – Compare at least two groups » Experiemental vs Control groups » IV & DV IV has a cause-and-effect r/ship w/ the DV » Random assignment to groups – Pre-test vs Post-test » Any difference btw the two groups can be attributed to differences in the experimental condition – Ethical concerns » Do no harm E.g., smoking » Use nonhuman animals 9

10. What is the source of health information? Use research methods – Ex Post Facto Desings Use when prevented by ethical or practical reasons Quasi-experimental design Contrast groups Not involve the manipulation of IV Subject variable: Choose a variable of interest & select participants who differ on this variable No random assignment! No causality! 10

11. Studies on epidemiology Epidemiology: The study of (logos) what is among (epi) the people (demos) – Branch of medicine that investigates factors contributing to increased health or the occurence of a disease in a particular population – Not accepted as a science until 19th century – Help to control infectious diseases (cholera, smallpox, etc.) – Chronic diseases in 20th century – Prevalence: The proportion of the pop that has a particular disease at a specific time period – Incidence: the frequency of new cases of the disease during a specified period 11

12. Studies on epidemiology Research methods in Epidemiology 1.Observational studies 2.Randomized, control trials 3.Natural experiments 12

13. Studies on epidemiology Research methods in Epidemiology 1.Observational studies Analyze the occurance of a specific disease in a given population No causal r/ship! Draw inferences only Similar to correlational studies Prospective studies: – Begin w/ a pop of disease-free participants – Follow them over a period of time to see whether a given condition is related to later condition – Cohort group: a group of participants starting an experiment together – Same w/ longitudinal desing when time period is long. Retrospective studies – Begin w/ a group of people already have a disease – Look back for characteristics – Also called case-control studies 13

14. Studies on epidemiology Research methods in Epidemiology 2.Randomized, control trials Same w/ experimental design Random assignment to the groups Pertinent factor, instead of IV When new drugs are tested, clinical trials are arranged – Food and Drug Administration (FDA) – The zenith of the hierarchy of research design : Randomized, placebo-controlled, double blind trials 14

15. Studies on epidemiology Research methods in Epidemiology 3.Natural experiments Only select IV, but no manipulation Similar to Ex post facto designs Differs from case-control studies – Not testing everyone w/ disease – Test individuals w/ disease who were born at a specific place and in a specific time period – No manipulation 15

16. What about causation? Risk factor approach – Famous w/ Framingham Heart Study (1948) A large-scale epidemiological study > than 5000 m & w participants included helped to identify risk factors for cardiovascular disease – Serum cholestrol levels, gender, high blood pressure, cigarette smoking & obesity 16

17. What about causation? Risk factor approach – Absolute risk vs Relative risk RR: the ratio of incidence/prevalence of a disease in an exposed group to the incidence/prevalance of that disease in the unexposed group. RR of unexposed group is always 1.00 – E.g., RR = 1.4 > exposed group is 40% more likely to develop the disease than the unexposed group. – E.g., RR = 6 > exposed group is 6 times more likely to develop the disease than the unexposed group 17

18. What about causation? Risk factor approach – Absolute risk vs Relative risk AR: person’s chances of developing a disease or disorder independent of any risk that other people may have for that disease or disorder – E.g., RR for dying of lung cancer for smokers is 9.00. – AR is 0.001 in any one year. – Over 50 years,.05 – E.g., RR for dying of CVD is 2.0; RR for dying of lung cancer 9.0 – But CVD is more common than lung cancer – So have higher AR of dying CVD than lung cancer As the rareness of disease increases, increases RR but not AR. – USA Congress House Subcommittee on Health No scientific study proved a causal r/ship btw smoking & CVD and lung cancer 18

19. What about causation? Dose-response r/ship – Direct, consistant R/ship btw IV and DV – The higher the dose, the higher the death rate E.g., IV: Smoking behavior DV: CVD – # of cigarettes per day & # of years – The prevalence/incidence of a disease should decline w/ removal of the possible cause – The cause must preceed the disease – A cause-effect-relationship btw the condition & the disease must be plausible Requires logical biological viewpoint Findings w/ nonhuman animals add – Research findings must be consistent – The strenght of the association btw the condition & the disease must be relatively high – Existence of appropiately designed studies 19

20. Theory, Tools & Psychometrics Theory Model Hypothesis testing Measurement, labeling & categorization of observations Action quidance & prediction Reliability & validity – Inter-rater reliability – Test-retest reliability – Predictive validity 20

21. To be continued... 21