What is the nocebo effect?

Can fearing the worst make it more likely to happen? And how can this play out in the therapy room?

You’ve heard of the placebo effect, when someone’s physical or mental health improves after receiving a fake treatment (like a sugar pill) – but what about the nocebo effect?

Essentially the opposite of a placebo, the nocebo effect describes when someone’s expectations cause a treatment or experience to be worse than it otherwise would have been. For example, a doctor tells you an injection is going to hurt, and you feel the jab more than you may have otherwise.

Derived from the Latin word meaning ‘I will harm’, it’s an effect that has been well studied. Fabrizio Benedetti is an Italian neuroscientist and physician who is also one of the world’s leading experts on the placebo and nocebo effects. Prior to his work, these phenomena were dismissed as purely psychological, but his research has shown that our expectations can produce measurable changes in brain activity, neurochemistry, hormone release, and pain processing. In short, something that starts in the mind has a real effect, including increased pain signalling, activation of anxiety pathways, and increased stress hormones.

But the nocebo effect isn’t just present in medicine, but plays a role in therapy and mental health care, too. A 2018 study published in the journal Psychotherapy found that a person’s expectations (among other considerations such as the therapeutic approach, the therapist-client relationship, and symptom severity) about whether therapy will be able to help them is among the strongest predictors of the outcome. With this in mind, researchers have called for greater attention to be given to the nocebo effect in mental health care.

For therapist Carly Turner, this effect is something that she sees first-hand.

“It’s not unusual for therapy to feel challenging at first, or for minor ruptures to occur in the therapeutic relationship,” she explains. “Clients who expect therapy to be unhelpful can be more likely to interpret these experiences as evidence that therapy is not working or isn’t right for them, which in turn increases the risk of feeling bad, poorer outcomes, and premature dropout.”

Beyond how someone may react to therapy, Carly also highlights how the nocebo effect can impact our behaviours. For example, someone with relationship anxiety might have expectations about being left or rejected. Because of this worry, they begin to look for signs that something is wrong. This then increases their anxiety and distress, which makes them even more uneasy.

“It may be seen also when working with long-term conditions or anxiety related to health,” Carly adds. “That’s because usually expecting pain or bad health can activate the body’s stress response. It’s suggested that stress hormones (like cortisol) can intensify symptoms such as tiredness or tension. Anxiety also makes people pay closer attention to normal bodily sensations, so they may interpret them as signs of illness. This, in turn, creates a cycle where the misinterpretation leads to fear and anxiety, which increases symptoms, which leads to more anxiety and distress – a vicious cycle.”

So what could it be that makes one person more susceptible to the nocebo effect than another? One thing Carly points to is learned experiences.

“If someone has been repeatedly or significantly let down by people or systems throughout their life, they may now have a generalised lack of trust. Early upbringing and relational experiences can also shape someone’s thinking and expectations; for example, if they witnessed caregivers being negative or critical, they may well adopt a similar mindset.”

The fact that this is a widely studied and current topic may feel supportive for some. The way that we think and feel about things really can impact the outcome – and that’s a normal, and human, thing to experience.

But where it can become more of a challenge is if negative expectations are routinely causing issues, and if this is becoming a barrier in your life or in attempts to improve your wellbeing.

“My advice would be to discuss any doubts or concerns with the healthcare professional involved in care,” says Carly. “If they do not respond with compassion and understanding, if possible it is worth seeking support from another professional. Feeling heard and receiving genuine compassion and psychoeducation about treatment, and what to expect, can make a significant difference to someone’s experience.”

As an example, Carly says that someone explaining that you can temporarily feel worse before you begin to feel better can help normalise this experience. And so when someone understands that this can be a typical part of the treatment process, they may be less likely to lose hope or discontinue treatment prematurely, as they feel reassured that things can still change and improve

“Another piece of advice is to record even the smallest shifts or improvements throughout your recovery,” she adds. “Intentionally paying attention to small, meaningful changes and writing them down can help someone recognise that change is taking place. Progress is often gradual rather than dramatic, so these small improvements can provide evidence that change is happening, even when it doesn’t feel obvious to someone. Looking back at these records can also increase hope, motivation, and confidence, during times when recovery feels slow or challenging.”

While the nocebo effect is inherently negative, knowledge of its existence and where it might show up in our lives, and the lives of others, is quite the opposite. Our minds are powerful machines, sometimes a little too powerful, and when we understand that, we’re in a better position to work with them.