Introduction to the design and evaluation of clinical trials for psychotherapy research Flashcards

1
Q

What is the definition of psychotherapy by Campbell and colleagues (2012)?

A

“the informed and intentional application of clinical methods and interpersonal stances

  • derived from established psychological principles
  • for the purpose of assisting people to modify their behaviour, cognitions, emotions, and/or other personal characteristics
  • in directions that the participants deem desirable”
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2
Q

What is the purpose and method to gather evidence for the foundational principles of psychology?

A

> Evidence-based therapy

> Evidence best derived from the application of robust and reliable empirical methods

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3
Q

What is the purpose of gathering evidence for the effectiveness of psychotherapy?

A

> Ethical
- use methods that we know are useful

> Economic

  • use the most cost-effective approach
  • acknowledging that one-size-fits-all approach is not appropriate
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4
Q

What are the 3 characteristics of evidence that can be used to demonstrate that a treatment is effective in healthcare (not specific to psychotherapy)?

A
  1. Robust
  2. Unbiased
  3. Objective
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5
Q

What is the problem of using anecdotal reports, expert opinions and testimonials for evidence?

A

Subjective and highly prone to bias

-> weak evidence

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6
Q

What is the problem of using observational studies, uncontrolled case studies and case series for evidence?

A

> Very subjective
Subject to possible bias from multiple sources

-> weak evidence

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7
Q

When are controlled case studies useful for evidence?

A

In the early stages of therapy development

- prelude to clinical trial

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8
Q

What is the problem of cohort studies?

A

> Observational

> Do not control for biases that might have led to one patient receiving a treatment and another not

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9
Q

What is the ‘gold standard’ for evaluating therapy outcomes?

A

Randomised controlled trials (RCTs)

- general paradigm for treatment evaluation

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10
Q

What can be considered as the strongest source of evidence for treatment effectiveness? Why?

A

Systematic reviews and meta-analyses

- combined RCTs

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11
Q

What are the steps of building a randomised controlled trial (RCT)?

A
  1. Feasibility
    - demonstrate the the full RCT is feasible
  2. Pilot
    - demonstrate and refine methods
    - estimate size of the treatment effect (plan number of patients needed for RCT)
  3. Efficacy (most RCTs are efficacy trials)
    - assess the treatment in restrictive context of trials
  4. Effectiveness
    - assess the treatment in real-world clinical setting
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12
Q

How do you demonstrate the feasibility of an randomised controlled trial (RCT)?

A

Feasibility trial (mini-RCT)

  • run with some conditions of RCT
  • clear operational plans, objectives
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13
Q

When and how do you assess the effectiveness of a treatment?

A

> When treatment is shown to be effective (efficacy trial)

> Multiple factors

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14
Q

What is the limit of effectiveness randomised controlled trials (RCTs)?

A

They are the most expensive (hundreds of thousands of pounds)

  • assess the treatment in real-world clinical setting
  • requires time and a lot of participants

-> they are the least commonly used

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15
Q

What are the 5 characteristics of a randomised controlled trial (RCT)?

A
  1. Careful selection of cases
  2. Two or more ‘treatments’
  3. Randomisation of cases to treatments
  4. Random allocation to condition is ‘blind’
  5. Repeated assessment of outcome measures
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16
Q

What is the process to carefully select cases in a randomised controlled trial (RCT)?

A

> Inclusion criteria: take part
Exclusion criteria: ruled out

e. g.:
- reduce between-patient variability
- remove obstacles to the sage and effective delivery of treatment
- remove clinical confounding factors

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17
Q

What are the disadvantages of restrictive criteria in a randomised controlled trial (RCT)?

A

> Problems recruiting sufficient numbers

> Unrepresentativeness and lack of generalisability of results (due to small number of participants)

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18
Q

Why does a randomised controlled trial (RCT) require at least two or more ‘treatments’?

A

Fundamental aim: is a treatment effective

-> active treatment vs. control treatment

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19
Q

What are the two types of randomised controlled trials?

A

> Superiority trial
- new treatment is better than existing or no treatment

> Inferiority trial
- new treatment is no worse than the existing treatment

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20
Q

What are the types of control treatments used in a randomised controlled trial (RCT)?

A

> Placebo controlled

> Standard care, treatment as usual (TAU)

> Waiting list controlled

> Current ‘gold standard’ treatment

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21
Q

What is a placebo controlled RCT?

A

Control = dummy treatment without active ‘ingredients’

- placebo response (biological or psychological)

22
Q

What is the attention effect observed in clinical trials?

A

Patients in clinical trials receive lots of attention

  • researchers showing considerable interest in symptoms
  • maintaining contact over couse of the study

-> attention effect, potent in disorders such as depression

23
Q

What is a standard care or treatment as usual (TAU) controlled RCT?

A

> Control = treatment or care that patient would usually receive

> For psychological problems, TAU = no treatment

24
Q

What is a waiting list controlled RCT? What are its advantages?

A

Patients receive active treatment after a delay
vs. patient receive it immediately

  • practical and ethical advantages over standard care comparison (TAU)
25
Q

What is a current ‘gold standard’ treatment controlled RCT?

A

Control = best available treatment currently in use

  • new treatment may be as effective but easier, cheaper, quicker to deliver, or preferred by patients, or needs less highly trained staff
26
Q

Why are curent ‘gold standard’ treatment controlled RCTs very expensive?

A

Because both active and control treatments are effective, it requires a large number of patients

27
Q

What is the process of randomisation of cases of treatments in a randomised controlled trial (RCT)?

A

Which patient receives which treatment must be determined randomly
- adresses researcher, treating therapist, and patient

> Equalisation of groups
Prevention of allocation bias

-> enables ‘blinding’: unable to tell which condition a patient has been allocated to

28
Q

What is the equalisation of groups in a randomised controlled trial (RCT)?

A

Ensures groups are matched for severity of symptoms, age, gender and other factors

29
Q

What is the prevention of allocation bias in a randomised controlled trial (RCT)?

A

Investigators can not choose between active or control treatments for a patient
- would otherwise result in major systematic bias

30
Q

What are the potential disadvantages of the randomisation of cases to treatment in randomised controlled trials?

A

> Deterrent to recruitment

> Some patients may want to know what treatment they are going to receive
- hoping for effective one, and to receive it as quickly as possible

-> need for assessment of the feasibility of recruitment before commencing full scale trial

31
Q

Why is the random allocation to condition ‘blind’ in randomised controlled trials?

A

> Clinical trial = experiment where no-one knows the outcome
- there are multiple opportunities for bias from assessor, patient and statistician

> Minimise these biases:

  • avoid possibility of unconscious bias from assessor (expectancy)
  • stop patients giving response they think doctors want to hear
  • avoid patients focussing more on improvement attributed to active treatment
  • avoid bias in choice of analyses or interpretation of results

> Sometimes full blindness is impossible

32
Q

Which bias from the assessor is purposefully minimised in an RCT with the ‘blind’ random allocation to condition?

A

Expectancy bias:
- based on knowledge of which treatment condition patient is in, might nudge the researcher to give a symptom score more indicative of improvement in patients receiving the active treatment

33
Q

Which blindness of allocation to condition is an absolute minimum in a randomised controlled trial (RCT)?

A

Blindness of the statistician

34
Q

Why is there a repeated assessment of outcome measures in a randomised controlled trial (RCT)?

A

All clinical trials require a robust and reliable way to measure the symptom of condition of interest

35
Q

What are the types of outcome measures in a randomised controlled trial (RCT)?

A

> Primary outcome measure

  • main index used to measure effectiveness
  • accurate and reliable: measure of symptoms with minimal error
  • the more reliable the measure, the easier it is to detect treatment effect from trial

> Secondary outcomes
- measure other outcomes of interest

36
Q

What are the types of repeated assessments in a randomised controlled trial (RCT)?

A

> Multiple assessment points

  • repeat at baseline before randomisation
  • before and after treatment
  • main indicator of efficacy
  • potential intermediate assessment points during treatment period

> Follow-up assessment

  • to measure continuation of benefit after treatment ends
  • the larger the better
37
Q

What is the limit of follow-up assessments in randomised controlled trials (RCTs)?

A

The larger the better, but the more costly, particularly if blindness is maintained during follow-up

38
Q

What are the types of clinically meaningful outcomes?

A

> Minimal Clinically Important Change (MCIC)

  • a response greater than expected by chance or normal recovery
  • may be expressed on self-report scale (e.g. Beck Depression Inventory)

> Defined response criteria

> Short-term remission of symptoms (relative to baseline)

> Lasting recovery

39
Q

What are the three main challenges to designing and conducting robust RCT in psychotherapy research?

A
  1. Psychotherapy treatment
    - complex intervention
    - need to standardise how it is delivered
  2. Choice of control treatment
  3. Allocation blindness
40
Q

What makes the psychotherapy treatment part of an RCT challenging?

A

Standardisation:
> User treatment manual
- therapists should be trained to deliver therapy as defined in the manual

> Ensure adherence to treatment (Fidelity)

  • therapists regularly checked to ensure they follow the manual
  • variance of therapists may need to be incorporated in data analysis

> Assess therapist effects
- they may vary in expertise and other characteristics

41
Q

What is a user treatment manual in an RCT?

A

Restrictive description of treatment and delivery

42
Q

What makes the choice of control treatment in a psychotherapy RCT challenging?

A

> No psychotherapeutic equivalent to dummy pill

> Effective placebo control treatment almost impossible

> Requires two near identical treatments

> Must be equally plausible and convincing

  • without true match placebo condition, patients risk to know whether they’ve been allocated the active or control treatment
  • > risk of expectancy bias

> Extremely difficult to achieve in practice

> Regular assessments of treatment fidelity necessary
- particularly if therapists are delivering an alternative and presume less effective control treatment in which they have no faith

43
Q

What is the most common control in a psychotherapy RCT?

A

Another active treatment

- typically antidepressant medication

44
Q

What is the advantage of using antidepressant medication as control treatment in a psychotherapy RCT?

A

Ethical and practical advantage for recruitment

- all patients receive an effective treatment

45
Q

What did the study of Elkin and colleagues (1989) consist of?

A

Large multicenter study
- cognitive therapy compared to other active treatments

Randomisation:

  • cognitive therapy
  • vs. interpersonal therapy (IPT)
  • vs. antidepressant medication (tricyclic - TCA)
  • vs. pill placebo
  • N = 250 (239)
  • Duration: 16 weeks treatment
  • 32% stopped early
  • Outcome criterion: Remission
  • Completer patients analysis (N = 155) -> not significant
  • Intention-to-treat (N = 239) -> significant
46
Q

What was the result and limit of the study of Elkin and colleagues (1989)?

A

> Support for interpersonal therapy (IPT) as treatment for depression, and at lesser extent CBT

> Limit: sample size too low to test for differences between active treatments

47
Q

What were the research questions of the study of Rahmen and colleagues (2008)?

A

> Could CBT help depressed mothers with infant children in rural Pakistan?

> Would improving the mothers mental health improve the health and early development of her new born children?

48
Q

What did the study of Rahmen and colleagues (2008) consist of?

A

Applying CBT for depression in a low-income country

  • delivered by existing primary healthcare workers
  • trained to deliver CBT in centres randomised to active treatment
  • other centres delivered typical care (enhanced, closer than usual contact)
  • CBT vs. Enhanced typical care
  • N = 903
  • Duration = 16 sessions over 10 months
  • Assessment: baseline, 6 and 12 months
  • Outcome criterion: diagnosis, mother-baby interaction, infant health
49
Q

What makes the intention-to-treat analysis a preferred method of analysis in clinical trials?

A

Avoids possible biases such as patients dropping out at different rates in each treatment group and for different reasons

50
Q

What was the result of Rahmen and colleagues’ study (2008)?

A

> Cost effective CBT intervention has effects that go beyond the mothers’ acute mental health

  • > Other positive outcomes:
  • fewer cases of stunted growth
  • fewer cases of diarrhoea
  • increased rates of infant immunisation
  • increased use of maternal contraception
  • increased play with the mother and father

-> wider and potential long-term impact of untreated maternal depression on infant health and social adjustment