Ask Dr Bec: What is a placebo effect?

Narrabri-based scientist Dr Bec Thistlethwaite contributes a column to The Courier on the science in our daily lives. Readers are invited to send their science questions in to Dr Bec via [email protected]

The placebo effect is a fascinating example of how powerful the human brain can be.

In simple terms, it’s when someone experiences real improvements in their health after receiving a treatment that has no active medical ingredients – like a sugar pill or a saline injection – just because they believe it’s going to help.

Scientifically, the placebo effect is all about expectation.

When a person expects a treatment to work, the brain can release chemicals like endorphins and dopamine, which are natural painkillers and mood boosters.

These brain chemicals can genuinely reduce symptoms like pain, anxiety, or fatigue, even though the treatment itself is doing nothing directly.

This response isn’t just ‘in your head.’

Brain scans have shown that people experiencing the placebo effect can have measurable changes in brain activity, like what happens with real medication.

The body is responding to the belief in treatment, not the treatment itself.

Placebos are used in clinical trials to help researchers test whether a new drug actually works.

If a group taking the real drug improves more than the group taking the placebo, scientists can be confident the drug has a real effect – not just a psychological one.

But the placebo effect also shows us how deeply connected the mind and body are.

It highlights the role that expectation, trust, and even a doctor’s bedside manner can play in healing.

While placebos won’t cure serious diseases like cancer, they can make a big difference in how people feel – and in medicine, that can be incredibly powerful.