lecture 2: control groups

Question 1

Which control groups are possible?

Answer 1

1. waiting-list
2. TAU
3. active treatment
4. placebo
5. dismantling studies
6. no treatment

Question 2

How do you choose?

Answer 2

• based on rq

- pragmatic and ethical issues (where do you recruit, unethical to withhold treatment etc.)

Question 3

CG: no treatment

Answer 3

• they don’t expect a treatment offer
• rq: efficacy (optimal effects your intervention might give)
  issues:
• unethical (maybe prevention)
• cannot be carried out in treatment center (ethical issues)
• likely to drop out (no benefit, only burden bc filling out questionnaires)
  be aware: people might seek alternative treatment! (measure that!)
• more used: minimal treatment (1 page of psychoeducation…)

Question 4

CG: waitlist

Answer 4

• people will receive treatment a little later (usually not informed that they are on the waitlist, but are told that they receive the treatment immediately or in a few weeks/months)
• rq: efficacy: (same as no treatment): highest possible effect of intervention
• issues:
• some people might need immediate treatment (not ethical to withhold for a long time)
• probably cannot be carried out in research center (unethical)
• waiting for a treatment (being on a wait-list, expectations) may be different than natural course (they may remain ill, cause they are waiting) –> effects are overestimated
• no longer term follow-ups are possible (you can choose how long they have to wait though)

Question 5

CG: placebo

Answer 5

• common factors vs. specific factors
• Placebo: receive a (similar) treatment without the techniques of interest (specific factors)
  rq: effectiveness of the specific factors of the therapy
• issues:
• find credible placebo
• people might need to be informed that they might receive placebo, and then figure it out (ethics requirement)

Question 6

CG: care as usual

Answer 6

• care that would be received when there is no RCT
  -depends on where you recruit patients! (general population (nothing) vs. clinic (optimal care)) –> very heterogenic
  rq: is treatment more effective than current care (nothing/ optimal care…)?
  issues:
  -easy to recruit from an ethical perspective
• Patents in TAU might drop out (little benefit, extra burden)

Question 7

CG: other active intervention

Answer 7

• intervention against another (medication, therapy)
• NOT the same as CAU (because you choose what care is provided)
  rq: Is treatment A better/ not worse than treatment B?
  issues:
• difference in effect is small –> bigger sample needed