CBT for Major Depressive Disorder (MDD) (DP IB Psychology): Revision Note

Beck's model: the negative triad

• The cognitive approach explains behaviour through mental processes such as thinking, decision-making, memory, and perception

• In relation to MDD, the approach assumes depression results from faulty or irrational thought processes, where depressed individuals rely too heavily on cognitive biases

The cognitive triad

• Beck (1963) developed an explanation of MDD known as the cognitive triad, which was based on depressed patients he had worked with

• The cognitive triad is divided into three patterns of negative thinking: 

  • Negative view about the self, e.g., 'I'm worthless'

  • Negative view about the world, e.g., 'Nobody cares about me'

  • Negative views about the future, e.g., 'Things will never get better'

Features of depressed thinking

• Beck suggested that the irrational thought patterns below may stem from adverse childhood experiences

  • Personalisation: irrationally blaming the world or events on oneself (e.g., 'Everyone hates me – even the bus hates me because it didn’t stop')

  • Negative automatic thoughts: always seeking out the negative in situations (e.g., 'A promotion just means more stress')

  • Catastrophising: expecting the worst possible outcome (e.g., 'A low mark in this essay means I’ll fail the IB and end up broke')

  • Overgeneralisations: applying one negative event to all situations (e.g., 'What a bad date – I’ll never find anyone')

Diathesis–stress model

• Beck proposed a diathesis-stress component of his theory which states that some people are naturally predisposed to developing MDD

• Environmental stressors (e.g., job loss) may trigger depression in vulnerable individuals, while others may not be affected in the same way

• This means that MDD does not have universal triggers as one person's vulnerability is different to another person's and not all triggers are equal

CBT for MDD

• Cognitive Behavioural Therapy (CBT) is the most widely used psychological treatment for depression and is a practical application of Beck’s cognitive theory

• The focus is on the 'here-and-now' rather than the past

• The goal is to help clients identify, challenge, and replace irrational thoughts (from Beck’s negative triad) with more adaptive thinking while building independence

Techniques used in CBT

• Cognitive restructuring/reframing - turning negative thoughts into more positive ones

• Guided discovery – the therapist challenges irrational thoughts and beliefs

• Journaling – recording thoughts, feelings, and behaviours between sessions

• Activity scheduling/behavioural activation – encouraging action, reducing procrastination

• Relaxation techniques – deep breathing, muscle relaxation, visualisation

• Role-playing – practising difficult or anxiety-provoking scenarios

• Homework – e.g., recording positive events, which are then discussed in therapy

• A course of CBT usually lasts 5–20 sessions, once a week or fortnight, each lasting 30–60 minutes

Research support for CBT for MDD

March et al. (2007)

Aim: 

• To compare the effectiveness of CBT, SSRIs (fluoxetine), and combined CBT and SSRIs for treating adolescents with MDD

Participants: 

• 327 adolescents (aged 12–17) with diagnosed MDD from 13 US locations

Procedure: 

• The participants were randomly assigned to:

  • SSRI group

  • CBT group

  • Combined CBT and SSRI group

• The children were interviewed, and their responses were measured using the Children’s Depression Rating Scale (CDRS)

  • A score of >40 meant that MDD was present

  • A score of <28 meant that they were in remission

• The study ran for 36 weeks

Results: 

• After 36 weeks:

  • 81% improved in the SSRI group

  • 81% improved in CBT group

  • 86% improved in the combination group

• Suicidal ideation decreased in the CBT and combination groups, but not significantly in the SSRI-only group

Conclusion: 

• Adolescents respond well to CBT and to combined CBT and drug therapy

• Combining therapies may enhance the safety of medication and be the most effective treatment option

Evaluation of CBT for MDD

Strengths

• CBT is not a non-invasive therapy, as it involves no drugs or side effects, unlike biological treatments

• CBT is individualised, as sessions can be tailored to the client, allowing them to progress at their own pace and accounting for individual differences

Limitations

• The focus on the present may not be appropriate for people who need to revisit past trauma to recover

  • This limits the usefulness of the therapy, as it may not be effective for all

• Some people struggle with 'talking therapies' like CBT due to lack of confidence, willingness, or verbal/intellectual skills, which also limits the usefulness of the therapy

Link to concepts

Measurement

• The study presented above is longitudinal (conducted over a series of months), which means that progress can be assessed by measuring depression symptoms at specific points compared to the baseline measurements

  • The participants’ progress can only be properly assessed over time, which gives longitudinal research ecological validity (real behaviour measured in real time)

Bias

• Participants in the study were self-reporting using a rating scale, which means that they may have succumbed to social desirability bias (under-reporting their symptoms) or practice effect (i.e., they became used to filling in the questionnaire, so that their answers became less natural over time)

  • The researchers would have to consider how to guard against these forms of bias to preserve the validity of the findings