If you’ve ever lain awake rehearsing every possible outcome of tomorrow’s appointment, or found yourself avoiding decisions because you can’t be 100% sure of the right answer, you’re not alone. For many people living with depression and anxiety, uncertainty isn’t just uncomfortable — it feels unbearable. And the harder we try to resolve it, the worse we often feel.
Acceptance and Commitment Therapy (ACT) offers a different path: instead of trying to eliminate uncertainty, it teaches us to relate to it differently — with openness, curiosity, and a willingness to act on what matters.
Why Uncertainty Hurts
Intolerance of uncertainty (IU) is the dispositional tendency to react to the unknown with heightened distress, worry, and avoidance [1]. Originally studied in generalised anxiety disorder, it is now recognised as a transdiagnostic driver across anxiety conditions — including social anxiety, panic disorder, and OCD — and it amplifies repetitive negative thinking and inflexible coping [1, 2]. Longitudinal work shows that rising IU predicts subsequent increases in stress and depression via deteriorating emotion regulation [2].
The pattern is a trap: uncertainty triggers worry, worry drives avoidance, avoidance robs us of the experiences that would disconfirm the fear. Short-term anxiety is avoided, but in the longer term this interferes with skill development, progress, and growth [3].
Where ACT Comes In
ACT’s central target is psychological flexibility — the ability to stay present, open up to difficult thoughts and feelings, and move toward what matters. It acts as a buffer against the distress that uncertainty generates [4], and higher psychological flexibility has been repeatedly linked to lower depression, anxiety, and burnout [3, 5].
In practice, ACT shifts the question from “How do I make this uncertain?” to “How do I live well alongside uncertainty?”
Practical Shifts From an ACT Perspective
1. Defusion: Notice the thought, don’t fuse with it
Uncertainty shows up as thoughts like “What if something goes wrong?” or “I can’t handle not knowing.” Defusion helps us observe these thoughts as mental events rather than instructions to act. Naming them — “I notice my mind doing the ‘what-if’ thing again” — creates distance and reduces their grip.
2. Acceptance: Make room for the discomfort
Trying to push away the bodily and emotional signals of uncertainty tends to amplify them. Acceptance isn’t resignation — it’s willingness to let the feeling be there without fighting it. This is where the breath becomes a tool: not to change the feeling, but to create space around it.
3. Contact with the present moment
Much of the suffering around uncertainty lives in the future we’re trying to predict, or the past we’re trying to re-engineer. Grounding practices — a few slow breaths, noticing five things in the room — bring attention back to what is actually happening now.
4. Values: Know what matters, then act anyway
When uncertainty paralyses us, values are the compass. Instead of “What should I do to feel safe?”, the ACT question becomes “What matters to me here, and can I take a small valued action even while the uncertainty is present?” Acting on values builds evidence that we can do hard things alongside discomfort.
5. Committed action: Take the next step
Big decisions feel impossible when we demand certainty. Break them down. A small, concrete, values-aligned step — one email, one walk, one honest conversation — moves us forward and, over time, strengthens psychological flexibility.
What the Evidence Shows
Across populations, greater psychological flexibility and tolerance of uncertainty buffer against the negative impact of uncertainty on mental health, including during periods of acute social disruption [4]. Interventions like ACT and mindfulness-based approaches enhance psychological flexibility and improve tolerance of uncertainty [3, 4]. Stronger cognitive flexibility and executive control weaken the link between intolerance of uncertainty and emotional dysregulation — reinforcing that these are skills that can be developed [2].
A Starting Point for the Week Ahead
Pick one area where uncertainty is loud. Try this sequence:
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Pause and name the thought out loud (“There’s that ‘what if’ again.”)
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Notice the physical sensation without trying to fix it.
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Ask: What matters to me in this situation?
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Take one small valued action, uncertainty and all.
You don’t need to feel certain to move. You just need to move in a direction that matters.
References
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Carleton, R. N. (2016). Into the unknown: A review and synthesis of contemporary models involving uncertainty. Journal of Anxiety Disorders, 39, 30–43.
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Jensen, D., Cohen, J. N., Mennin, D. S., Fresco, D. M., & Heimberg, R. G. (2016). Clarifying the unique associations among intolerance of uncertainty, anxiety, and depression. Cognitive Behaviour Therapy, 45(6), 431–444.
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Kashdan, T. B., & Rottenberg, J. (2010). Psychological flexibility as a fundamental aspect of health. Clinical Psychology Review, 30(7), 865–878.
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Smith, B. M., Twohy, A. J., & Smith, G. S. (2020). Psychological inflexibility and intolerance of uncertainty moderate the relationship between social isolation and mental health outcomes during COVID-19. Journal of Contextual Behavioral Science, 18, 162–174.
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Kashdan, T. B., & Rottenberg, J. (2010). Psychological flexibility as a fundamental aspect of health. Clinical Psychology Review, 30(7), 865–878.