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What is Acceptance Commitment Therapy? (ACT)
The Mello Team
TLDR:
Acceptance Commitment Therapy is a type of therapy that helps you to accept your thoughts and feelings rather than control or change them. It also helps you identify what matters most to you and take meaningful steps in that direction. In this article, we explore the methodology behind ACT, the benefits of ACT, and how to access ACT support.
OVERVIEW
Written 12 June, 2026
WRITTEN BY
The Mello Team
Acceptance Commitment Therapy (ACT) is a practical, evidence-based approach to managing thoughts, feelings and behaviours in your daily life.
Unlike other therapeutic treatments like Cognitive Behavioral Therapy (CBT) that seek to identify and change thoughts, ACT teaches us to acknowledge, understand, and accept our feelings without judgement.
The core principles of ACT centre on self-acceptance and moving forward with values-aligned behaviours.
Intro to Acceptance Commitment Therapy
ACT was initially developed in the late 1980s by psychologist Steven C. Hayes and his colleagues. Hayes developed the treatment to fill a gap within existing cognitive and behavioural therapies that he deemed limited due to their focus on reducing a person’s symptoms rather than promoting a broader improvement in general psychological well-being.
Acceptance Commitment Therapy emerged from these traditional behavioural therapies (like CBT and DBT among others) by combining self-acceptance and mindfulness techniques with behavioural change.
One of the purposes of Acceptance Commitment Therapy is to reduce the struggle we have with our thoughts and feelings, rather than seeing them as something to be ashamed of or pushed away. Once this acceptance has been fostered, the ACT framework supports you to focus on aligning your current and future behaviour with your personal values to lead a life that feels meaningful to you.
ACT helps reduce the impact of difficult thoughts and feelings by changing your relationship with them, making it easier to move forward and build a life guided by your values.
How does ACT work?
Many of ACT’s roots are in Relational Frame Theory (RFT), which is a psychological framework that explores our relationship between our thoughts, feelings and our identity. RFT suggests that as people, we often create associations between words, concepts and experiences – and that these associations shape how we think and feel.
A key challenge this can create is when we perceive our internal thoughts as absolute truths, rather than acknowledging and understanding them as mental events that arise and pass. This is known as cognitive fusion.
For example, you may treat the thought ‘I’m a failure’ as an absolute fact, rather than a thought your mind has produced in a given moment. When fused with our thoughts in this way, we often respond by trying to avoid our thoughts or feelings, and the circumstances that trigger them. Over time, this pattern can worsen our mental health and make it harder for us to lead meaningful, well-rounded lives.
The key principles of ACT
ACT is built around six core processes that work together to develop psychological flexibility – the ability to accept difficult thoughts and feelings without being controlled by them, while taking action guided by your personal values.
The key ACT processes are:
1. Acceptance
Acceptance involves making room for your emotions and thoughts (including the unpleasant ones) rather than struggling with them or avoiding them. ACT sees all emotions and thoughts as part of our natural and normal human experience, which can help foster a sense of self-compassion.
Acceptance is not about giving up, liking or agreeing with your thoughts and feelings, it is about making room for them so they have less power over you and your behaviour.
2. Cognitive defusion
Cognitive defusion helps you create psychological distance between you and your thoughts. This way you can see your thoughts as passing mental events, rather than absolute facts.
Instead of ‘I am a failure’, cognitive defusion helps you recognise ‘I am having the thought that I am a failure’, which creates distance and reduces the thoughts grip on you.
3. Being present
Being present and mindful is an integral part of ACT. This principle focuses on maintaining non-judgement awareness of your present reality, and in turn reduces your chance of thoughts spiraling as you are paying keen attention to the moment, rather than ruminating on past or possible future events.
4. Self as context
Similar to cognitive defusion, this ACT principle focuses on separating us as the self from the thoughts we have. Specifically, this principle helps you recognise that you are not your thoughts, feelings or experiences – you are the person who observes them.
Think of it like being the sky rather than the weather; the weather changes constantly, but the sky always remains. This can create a stable sense of self, even when thoughts or feelings change.
5. Values clarification
Along with acceptance, values driven behaviour is the other key part of ACT. Values clarification seeks to support your mental well-being by making you aware of what is genuinely meaningful to you and in turn, supporting you to lead a purpose-driven life, aligned with your personal values.
This also limits you from being driven by your emotions and instead focuses on behaviour that aligns with your values.
6. Committed Action
This principle is focused on goal-setting and practical behaviours. Committed action means taking concrete steps towards goals that are in line with your values, managing obstacles that may pop up, and persevering so you can lead a meaningful life that’s in line with your purpose, goals and values.
While you commit to acting in line with your values, you’re able to focus more squarely on what you can control, rather than the emotions or thoughts you can’t.
Each of these principles are used together in ACT to support you to live a meaningful life aligned to your values and foster an acceptance of self without shame or judgment.
In conclusion: each of these principles are used together in ACT to support you to live a meaningful life aligned to your values and foster an acceptance of self without shame or judgment.
What’s the evidence for ACT?
A large and growing body of evidence supports ACTs effectiveness across a wide range of mental health challenges. Meta-analyses (which look at results across a wide range of studies) have found ACT to be effective in reducing symptoms of depression, anxiety, chronic pain and stress, as well as improving overall quality of life.
Research also supports ACT’s effectiveness specifically with young people, with promising results across a range of challenges, including anxiety and depression.
How does an Acceptance Commitment Therapy session work?
Acceptance Commitment Therapy is often administered in sessions with a registered psychologist. These sessions are commonly one on one and may repeat weekly depending on what symptoms you present to your psychologist with.
ACT’s central focus is psychological flexibility and value driven actions. Psychological flexibility refers to a person’s ability to accept their thoughts and feelings, remain present and undertake behaviour and actions aligned to their personal values, even when they are experiencing difficult emotions or thoughts.
In sessions, your psychologist may use a range of techniques or exercises drawn from the six core processes of ACT. Every person's experience of ACT will look different, depending on what brings them to therapy, but some common elements include:
Mindfulness and acceptance exercises to help you practice staying present with your thoughts and feelings, rather than avoiding or being pulled away by them.
Practicing defusion techniques to help you create distance between you and your thoughts.
Values exploration to help you identify what genuinely matters to you and what kind of person you want to be.
Metaphors and imagery. ACT is well known for using creative metaphors to explain concepts in an accessible way, such as imaging your thoughts as passing clouds or visualising your emotions as a colour.
Committed action planning to help you set small, concrete goals that are guided by your values, building momentum gradually over time.
Reflection on avoidance patterns to help you notice where you might be organising your life around avoidance of difficult feelings and gently exploring what avoidance might be costing you.
ACT sessions are collaborative and non-judgmental, with a focus on helping you change your relationship to your thoughts and feelings (not getting rid of them) and on helping you move towards the life you want to be living.
The number of sessions varies depending on individual circumstances, but ACT is often delivered as a short-to-medium term therapy. Some people also access ACT in group settings.
How can I get Acceptance Commitment Therapy ?
Start by talking to your GP or a mental health service — they can refer you to a psychologist or therapist.
In Australia, you may be able to access subsidised sessions through a Mental Health Care Plan (MHCP). To get a MHCP, you need to speak to your GP.
Some schools, headspace centres, or digital programs offer ACT-based support. ACT is also available in self-help formats if you prefer to try it on your own.
How does ACT relate to Mello?
Treatments like ACT, DBT and CBT are designed to support those suffering from mental health disorders like anxiety and depression. Mello is designed to support you through stuck thinking, something that is a key driver of both anxiety and depression. Stuck thinking is when you repeatedly go over negative thoughts in your mind, otherwise called worry and rumination.
The Mello app supports you with exercises, techniques and tools to get unstuck the moment you need to.
In Mello, you’ll learn techniques like reframing thoughts and seeing problems from different angles. You’ll practice self-compassion and separating yourself from your thoughts. Everything in Mello is designed with young people, so it feels relevant and easy to use.
Further ACT Resources
A-Tjak, J. G. L., Davis, M. L., Morina, N., Powers, M. B., Smits, J. A. J., & Emmelkamp, P. M. G. (2015). A meta-analysis of the efficacy of acceptance and commitment therapy for clinically relevant mental and physical health problems.
Ruiz, F. J. (2012). Acceptance and commitment therapy versus traditional cognitive behavioral therapy: A systematic review and meta-analysis of current empirical evidence.
Swain, J., Hancock, K., Dixon, A., & Bowman, J. (2015). Acceptance and commitment therapy for children: A systematic review of intervention studies.
OVERVIEW
Written October, 2025
WRITTEN BY
The Mello Team
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