What is Acceptance and Commitment Therapy and why is it important?
Acceptance and Commitment Therapy is known as “ACT” not the letters A-C-T. ACT gets its name from its core messages which are to “accept what is out of your personal control, and commit to taking action that enriches your life” (Harris, 2009; p2). ACT helps us to do this by:

• Teaching psychological skills to handle painful thoughts and feelings effectively, in such a way that they have much less impact and influence – these are known as mindfulness skills, and
• Helping to clarify what is truly important and meaningful to us – that is, clarify our values – and use that knowledge to guide, inspire and motivate us to set goals and take action that enriches our life.

The primary aim of ACT is to increase psychological flexibility. Psychological flexibility is the ability to be in the present moment with full awareness and openness to our experience, and to take action guided by our values (Harris, 2009; p12).

Central to the philosophy of ACT is that (a) quality of life is primarily dependent upon mindful, values-guided action, and that (b) this is possible regardless of how many difficult events or painful experiences we have. These painful experiences include all kinds of mental health and substance use problems, along with traumatic life events. The key is to respond to the painful experience or the symptoms of mental health problems with mindfulness. In this way ACT involves a radical paradigm shift from dominant Western models of mental health care. The aim is not to reduce or avoid painful experience but to fundamentally change our relationship with it so that it no longer holds us back from valued ways of living.

A central idea in ACT is the distinction between pain and suffering. Psychological pain is normal and everyone has it (Hayes & Smith, 2005). We cannot get rid of psychological pain because adverse experiences are inevitable and we cannot stop our thinking minds from remembering past pain and anticipating future pain. Suffering is also normal and universally experienced, but it is different from pain because it is something that we create for ourselves through how we respond to our pain. While suffering is as normal and widely found as pain, it can be substantially reduced. Suffering arises because the “normal psychological processes of the human mind readily become destructive, and sooner or later create psychological suffering for all of us” (Harris, 2009; p6). Suffering arises because as human beings we engage in mental struggle with our pain. Because we try to avoid and suppress our unpleasant memories, our unwanted thoughts, our unwelcome urges and sensations, we end up creating even more discomfort in the form of worry, dread and resentment about our experience. Hayes and Smith (2005) use the metaphor of struggling in quicksand [see p3-4] to describe suffering. The more we struggle to escape it the more it sucks us down into its depths. Some methods of avoiding pain like alcohol and drug use can suppress it for a while, but end up causing even more pain in the future. Trying to avoid pain can also hold us back from living the kind of life we want. If we withdraw from activities that cause anxiety or sadness our lives become smaller. If we reflect on our own struggle we can see how this affects us all (see Hayes & Smith, 2005; p14-15).

ACT describes and teaches ways to move past this suffering based on struggle with our thoughts into a fuller engagement with life. It involves six core processes: (i) Contacting the present moment; (ii) Defusion; (iii) Acceptance; (iv) Self-as-context; (v) Values, and (vi) Committed action. The practice elements described here are organised around these processes, but it is vital to understand that they are highly interdependent and cannot be easily or usefully separated from one another. Harris (2009; p10-12) describes these six processes as six facets of one diamond called The ACT Hexaflex with Psychological Flexibility at its centre.

While an ACT therapist would introduce the concepts of these six processes one at a time, s/he needs to constantly move back and forth between all of them regularly. Understanding and mastery of each process is clarified and enriched by reference to the others. For this reason it is important to be familiar with all of these practice elements before you attempt to use any particular one.

When should it be used?
ACT interventions are useful in helping clients to deal more effectively with painful emotions and feelings such as frustration, disappointment, rejection, loss and failure, particularly when these feelings are persistent and are getting in the way of taking positive action. ACT can be useful for everyone because all human beings experience these painful feelings, and all of us have times when we get stuck in them and find it difficult to move on. 

Further reading
The theory underpinning ACT is called Relational Frame Theory. This explains how the language-based processes of the human mind inevitably create psychological pain, and why trying to avoid and suppress it leads to suffering. Hayes and Smith (2005) describe this in Chapter 2 of their workbook.