Background to depression treatments

Traditional treatments like cognitive behavioural therapy (CBT) are effective but often difficult to access due to long waiting lists and the need for trained clinicians. This has led to the development of more accessible alternatives, such as internet-based cognitive behavioural therapy (iCBT), which delivers CBT principles through online programmes, and cognitive-bias modification (CBM), a computerised training method designed to directly alter negative cognitive biases associated with depression.

These innovations aim to make treatment more cost-effective and widely available, addressing the limitations of face-to-face therapy.

Aims of the study

The study by Williams et al. (2013) sought to investigate whether combining CBM with iCBT could provide an effective treatment for depression.

Method and procedures

The study used an experimental design with random allocation to groups, allowing researchers to compare the effects of the combined treatment against a control condition.

Participants

Participants were 69 adults recruited through a clinical research unit in Sydney, Australia. They were screened using online questionnaires and telephone diagnostic interviews to confirm they met criteria for depression. Participants provided electronic informed consent before being randomised to either the intervention group (n = 38) or the waiting-list control (WLC) group (n = 31).

Measures

Several tools were used to assess symptoms before, during, and after the intervention:

Primary measures:

• Beck Depression Inventory, 2nd edition (BDI-II) - Measures the severity of depression symptoms.
• Kessler Psychological Distress Scale - Evaluates levels of psychological distress.

Secondary measures included assessments of disability, anxiety, and repetitive negative thinking.

Procedure

The entire study was conducted online, with no face-to-face contact, to test the feasibility of remote delivery.

Study stages:

1. All participants completed baseline measures of depression and distress.
2. The intervention group completed the CBM component first: seven 20-minute sessions of imagery-focused CBM, done daily over one week.
3. After the CBM week, the intervention group proceeded to the iCBT component: the Sadness Program, consisting of six online lessons based on best-practice CBT principles, delivered over ten weeks.
4. The WLC group waited during these periods and completed the same measures at matching time points (after one week and after ten weeks total).
5. Post-intervention, all participants repeated the questionnaires. The WLC group then received deferred iCBT treatment.

This structure allowed comparison of immediate effects from CBM and longer-term effects from the combined programme.

Results

The study produced quantitative data on symptom changes, analysed through mean scores and percentage reductions.

Baseline comparisons

Initial measures showed similar levels of depression and distress between the intervention and WLC groups, ensuring a fair starting point for comparisons.

Immediate effects after CBM

The intervention group experienced reductions in both depression (measured by BDI-II) and distress (measured by Kessler scale) scores after just one week of CBM training.

Longer-term effects at week 11

Both groups demonstrated significant reductions in all primary measures (depression and distress) by the end of the study period. However, the intervention group achieved greater improvements, with a 65% reduction in symptoms compared to 36% in the WLC group.

Conclusions and implications

The study concluded that internet-delivered CBM can lead to rapid symptom reduction in depression, with effects visible after just seven 20-minute sessions over one week. This reduction was partly explained by changes in imagery-based interpretive biases.

Key implications

• Therapeutic potential - Combining CBM with iCBT appears feasible and effective, potentially working by enhancing brain activity related to positive emotions or increasing optimism.
• Future applications - These results support integrating bias modification into existing online therapy programmes, which could improve outcomes for depression treatment on a broader scale.