IB Psychology SL Topic 1 — Mental Health Disorders Paper 1 & 2 Cognitive approach ~10 min read

Beck’s Cognitive Model of Depression

Two people fail the same driving test. One shrugs and rebooks it. The other decides they are a failure at everything. Same event, completely different reaction — and for Aaron Beck, that gap is where depression lives. Not in the event, but in how it gets interpreted.

📚 What you need to know

The cognitive triad

Beck built his theory from working with depressed patients and noticing that their thinking kept falling into the same three grooves. He called it the cognitive triad.

Beck’s cognitive triad as a loop Three beliefs that keep handing the problem to each other Negative view of the self “I am worthless” Negative view of the world “Nobody cares about me” Negative view of the future “Nothing will get better” depressed mood Each belief feeds the next, so the loop keeps itself going. Breaking any one link is exactly what CBT tries to do.
The triad is usually drawn as a plain triangle. Drawing it as a cycle is more useful, because it shows why depression is so hard to get out of on your own: every belief supplies evidence for the next one.

Follow the loop with a real example. You think you are worthless, so you stop messaging your friends. They stop messaging back. That looks like proof that nobody cares. If nobody cares now, why would that ever change? And a future with no hope in it makes you feel even more worthless. The loop has now gone round once and got tighter.

This is the answer to the question people ask about depression: “why can’t they just think positively?” Because the negative thoughts are generating their own evidence. It is not stubbornness, it is a closed system — and that is why an outside intervention like CBT is needed to break in.

Features of depressed thinking

Beck suggested these irrational patterns often trace back to adverse childhood experiences. Learn all four with an example each — short-answer questions love them.

PatternWhat it doesExample
Personalisation Blames yourself for events that had nothing to do with you. The bus drove past without stopping, so even the bus is against me.
Negative automatic thoughts Instantly finds the bad angle in any situation, without choosing to. I got promoted, which just means more stress and more chances to fail.
Catastrophising Jumps to the worst possible ending, skipping every step in between. One low essay mark means I will fail the IB and never get a job.
Overgeneralisation Turns one bad event into a permanent rule about everything. That date went badly, so I will never find anyone.

The diathesis–stress part

Beck’s theory is not only about thinking. He added a diathesis–stress component: some people are naturally predisposed to developing MDD, and an environmental stressor such as losing a job can trigger it in them while leaving someone else unaffected.

Why the same event breaks one person and not another Vulnerability and stress add together MDD threshold vulnerability stress vulnerability stress Low vulnerability same stress, stays below High vulnerability same stress, crosses over Vulnerability alone is not enough. Stress alone is not enough. It is the total that has to cross the line.
The stress block is exactly the same size in both columns. That is the whole point — the event has not changed, only the person it lands on.

This also explains why MDD does not have universal triggers. One person’s vulnerability is different from another’s, and not all triggers carry the same weight for everybody.

Evaluating Beck’s model

Strengths

  • Good research support: Bothwell and Scott (1997) found cognitive biases were linked to depressive symptoms.
  • Strong practical application — the model directly underpins CBT, which helps patients identify, challenge and replace irrational thoughts.
  • It treats the patient as an active thinker, not a passive victim of their chemistry.
  • The thinking patterns are specific enough to be measured and tested.

Limitations

  • Limited explanatory power: it explains how irrational thinking works but not why it develops in the first place.
  • Culturally biased — it focuses on individual thoughts and one-to-one therapy, which fits individualistic cultures better than collectivist ones.
  • The direction of causality is unclear (see below).
  • It underplays biology, poverty, abuse and other real-world causes.

The causality problem

Beck said negative thinking leads to depression. But the opposite is just as believable: being depressed makes you think negatively. Is it possible to think yourself into depression, or does depression produce the thoughts?

Most of the supporting evidence is correlational — researchers find depressed people also have cognitive biases. That tells you the two go together. It does not tell you which one arrived first. Say this in an evaluation and you have made a proper causality argument rather than a vague one.

Change. Beck’s model does not really account for how unpredictable depression is. A person is not depressed in the same way all the time — symptoms shift, ease and return. A model built on stable thinking patterns struggles to explain that.
EXAM ANSWER

Evaluate one cognitive explanation of one disorder. [22 marks]

Open with the mechanism, not the man Beck’s model says MDD is maintained by the cognitive triad: negative views of the self, the world and the future, each reinforcing the others. Show it in action Add one faulty pattern with an example, e.g. catastrophising: one poor mark becomes proof of total future failure. Strength — make it about consequences Its practical value is huge: CBT is built on it and reduces symptoms by challenging those thoughts. A theory that produces a working treatment has earned some credibility. Limitation — attack the direction, not the idea The evidence is correlational, so negative thinking may be a symptom rather than a cause. Conclude: strong on maintenance, weak on origin that one phrase does more work than a whole paragraph of hedging

💡 Exam tips

⚠ Common mix-ups

Up next: Negative Schemas and Depression — Beck told us what depressed thinking looks like. Schema theory tries to answer the question he left open: where did that thinking come from?

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