williams et al Flashcards
describe the aim of william et al’s study
to investigate the effectiveness of a brief 7 day internet-delivered imagery-based cognitive bias modification (CBM-I) as a “stand-alone” intervention for depression and in combination with a 10 week iCBT (online CBT) program, also delivered remotely on the Internet.
The study explored whether preparing Pps with the CBM-I would optimize engagement with the more challenging iCBT (online) components.
describe the sample used in william et al’s study
clients recruited by an australian (Sydney) clinic - 69 volunteers
what is the independent variable in william et al’s study?
what is the dependent variable in william et al’s study?
describe the procedure in william et al’s study
- The entire assessment and intervention was conducted online with no face-to-face contact
- First/pre-treatment baseline measure: All patients first completed baselines measures of their depression, distress, anxiety and thinking biases
- Intervention: The treatment condition (38 Pps) completed the 7-day CBM-I component, the other 31 were on the waiting list (WLC)
- Second measure - after CBM-I: All patients then completed the primary measures again after the 7-day intervention phase (1 week).
- Intervention: Next the experimental group completed the 10-week iCBT component, whilst the others were again “on the waiting list”.
- Third measure - after iCBT: All patients completed the baseline battery of questionnaires again after 10 weeks, apart from AST-D and SST (these only relate to CBM-I programme)
- Intervention: The WLC group then commenced deferred treatment (iCBT but without CBM-I).
in williams et al’s study, primary measures were taken of depression severity and distress using what?
- Depression severity = The Beck Depression Inventory–2nd edition (BDI-II) and the nine-item Depression Scale of the Patient Health Questionnaire (PHQ-9)
- Distress = The 10-item Kessler Psychological Distress Scale (K10) Interpretation bias = Ambiguous Scenarios Test–Depression (AST-D) - two versions of the AST-D were presented in counterbalanced order
- Anxiety = State Trait Anxiety Inventory–Trait Version (STAI-T)
williams et al - findings
After the first week of CBM-I training there was a reduction in the depression scores and the distress scores in the treatment group with clinically significant changes evident in seven pps of the treatment group compared to only two in the WLC group
Week 11 showed clinically significant reductions across all primary measures for both treatment group and the WLC group, but the reductions were much bigger in the treatment group where 65% of pps showed clinically significant change compared to only 36% of WLC group.
williams et al - conclusions
williams et al - randomised control trial
evaluation
P - Randomised control trial
E - Williams et al ensured the 69 pps who were randomly allocated to either the Intervention group or the Waiting List Control group were not different in important ways (gender, comorbidity, antidepressants) by conducting a screening questionnaire.
T - Therefore this is a strength because they were able to draw cause and effect conclusions that show any differences in depression, distress, interpretation bias etc. (DV) was due to the interventions (IV) internal validity.
williams et al - generalisability
P - Generalisability: sample has low population validity.
E - 69 pps from Sydney, Australia (ethnocentric).
T - Therefore the results about the effectiveness of CBM-I and iCBT on unipolar depression can’t be applied to people in China, for example, especially due to cultural differences in the experiences of depression.
LOW generalisability
williams et al - reliability
Reliability: Psychometric tests such as the AST and BDI-II are standardised, which means they are the same for every pps and can be easily replicated to get similar results.
E - The self-report method provides quantitative data which can be objectively analysed eg. 65% of treatment group showed clinically significant change compared to only 36% of WLC group.
T - This is a strength because clear and unbiased comparisons and checks on statistical significance can be made.
HIGH reliability
williams et al - internal validity
(qual data)
P - low Internal Validity: There is a lack of in-depth qualitative data about depression.
E - Psychometric tests such as the depression measure BDI -II and distress measure K-10, collect quantitative data, which is easy to analyse, however this is a weakness because there is a lack of detailed knowledge about pps experiences of depression.
T - Therefore clinical interviews could be used alongside psychometric self-report data to add depth, the use of triangulation could improve the internal validity of the data gathered.
williams et al - application
P - Application:
E - The study shows that computer-based therapy is effective very quickly (10-11 weeks), which means people in need can access it quickly and conveniently rather than waiting to see a therapist to complete face to face CBT. Also the addition of just seven extra days to the CBM-I was very effective.
T - This is a strength because accessing online treatment would reduce NHS costs. However, there is no information about the long term effects of CBM-I and iCBT treatment.
williams et al - internal validity
(lack of control of ext. variables)
P - low Internal validity
E - Despite some controls in the procedure such as no face-to-face contact, controlled interventions (CBM-I = 20 min sessions over 7 days and iCBT = 6 online sessions over 10 weeks with homework), there was a lack of control over extraneous variables which may have happened to the pps over the time period such as significant life events which would have affected motivation, change in medication or lifestyle (diet, sleep, exercise).
williams et al - ethics
Ethics: Consent - volunteer sample- consented
Protection from harm - the placebo group received iCBT at the end of the experiment.
The study was approved by the Human Research Ethics Committee (HREC) of St. Vincent’s Hospital in Sydney and the HREC of the University of New South Wales, also in Sydney.
