When guilt becomes unbearable, we may protect ourselves through anger and blame others for how we feel.

Self-critical thinking and depression go together. We believe that our problems are all our fault. We criticise ourselves because at the very least we feel as if we are in control and can manage our guilt. Being criticised by others is outside of our control and is worse because we then experience our raw guilt.

"Self-forgiveness might involve writing about how and why it is hard to forgive."

Self-criticism starts early. If our parents convinced us that there was something wrong with us, we believed them. After all they represented authority and whoever has authority always speaks the truth. Self-criticism, guilt and anger trap us. We may express them as rules such as “don’t express your feelings”. In CBT we try to tackle the rules. We try to put aside the rules in the knowledge that experiencing guilt, forgiving ourselves and letting go is more helpful.

In the film The Mission, Robert de Niro’s character Rodrigo kills his brother in a fit of anger. His rules keep him imprisoned him in a state of frozen guilt. He is unable to move on. Jeremy Irons, as Jesuit priest Gabriel, helps him break those rules. In doing so he experiences the full rawness of his guilt. His guilt is represented by the bag of weaponry he has used to kill others as well as his brother. He drags this bag through the jungle. When he lets go of the bag, he lets go of his past. He is forgiven and moves on with his life.

Anger is the opposite side of the coin from guilt. When guilt becomes unbearable, we may protect ourselves through anger, blaming others for how we feel. In doing this we will - as Paul Gilbert states in Compassion Focussed Therapy - keep ourselves imprisoned. We cannot move on. A technique he suggests is to write a letter (we do not send) to those who may have been harsh to us in the past. The contents of the letter will vary depending on the person. It simply needs to identify what will be helpful at that moment in time in helping to let go of the emotion. Self-forgiveness might mean writing about how and why it is hard to forgive.

Why is forgiveness important?

This is a different idea of forgiveness from what most people think. Forgiveness does not mean letting people off the hook or liking them. It is about letting go of feelings of anger and guilt in order to stop our current depression from becoming our future one. As Frank McCourt, an author, states, holding onto anger is like taking a poison and hoping that the perpetrator dies.

The philosopher Hannah Arendt reminds us how forgiveness is helped by remembering the role of luck in our lives. Because luck means being born into situations and families we did not choose, it was never really “our fault” in the first place. She says that although, the past is irreversible, we can try to work towards a different future. In CBT we plan SMART goals which are helped by people working towards their values. It is not risk free because we can never know the consequences of our actions. However, as Arendt says, doing this helps us to set up islands of security in the ocean of the future. It is the best we can do.

Michael O'Sullivan is a cognitive behavioural therapist and author.