Famous for his capacity to forgive his persecutors, Nelson Mandela is credited with the quote “resentment is like drinking poison and then hoping it will kill your enemies”. But many people experience a strong temptation to continue to drink the poison of resentment in vain. This often results in enduring low mood and depression that can have profound psychological, relational and physiological impacts.
What explains the roots of resentment and why is it so persistent?
It often stems from a sense of injustice, whether real or perceived. Many grievances, particularly those arising from structural inequalities, discrimination, or unfair treatment, may indeed be morally justified. Yet, remaining bound to these grievances comes with a heavy psychological toll. Chronic fixation on past wrongs narrows thinking, making realistic action toward restitution or reparation difficult. Instead, individuals ruminate and indulge in fantasies of revenge.
The hazards of prolonged resentment are manifold. Beyond depression and rumination, an inability to “let go” keeps the nervous system in a state of hyperarousal, mirroring post-traumatic stress patterns. Chronic hostility has been linked to hypertension, cardiovascular risk and a weakened immune system. Moreover, resentment is self-perpetuating: passive-aggressive communication, withdrawal and hostility alienate others, which reinforces feelings of injustice and isolation. Resentment has been identified as one of the primary factors leading to marital breakdowns, underscoring its deep relational consequences.
Paradoxically, neuroscience reveals why revenge is so tempting. Studies show that imagining or enacting revenge activates the dorsal striatum, a key component of the brain’s reward circuitry. These are the same centres implicated in addiction, explaining why revenge fantasies are psychologically “addictive”. However, as with all addictions, the pleasure is fleeting, while the long-term consequences – emotional exhaustion, relational damage, and physiological stress – are severe.
To address this, targeted therapeutic approaches are necessary. Central to many of these is the principle that self-forgiveness often precedes forgiveness of others. At the core of many grievances lies shame associated with the belief that one was powerless to resist harm. This internalised “despot” must be confronted before one can truly release anger toward others.
It is critical to ask: will revenge erase my loss? Will it enhance my wellbeing? Will it prevent recurrence of harm? Typically, the answer is no
Mindfulness and emotion regulation have proven effective in weakening resentment. Programs such as Jon Kabat-Zinn’s Mindfulness-Based Stress Reduction (MBSR) train individuals to observe bitterness with nonjudgmental awareness, thereby reducing its grip on cognition and affect. Forgiveness interventions, increasingly studied in positive psychology, provide structured pathways for emotional release. While forgiveness does not excuse harm, it alleviates the physiological and psychological burden of grudges.
One particularly well-researched model is Robert Enright’s forgiveness framework, which unfolds in four phases: uncovering anger, deciding to forgive, working through empathy, and deepening forgiveness to achieve emotional release. Neuroscientific studies show that thoughts of forgiveness, like revenge fantasies, activate the brain’s reward centres. However, unlike with revenge, these rewards are sustained, promoting long-term wellbeing. Repeated practice of forgiveness strengthens neural pathways favouring prosocial reward circuits over aggression.
The importance of forgiving is illustrated in the case of Marla*, a middle-aged woman overwhelmed by resentment after being betrayed by her business partner. Initially consumed by fantasies of public retaliation, Marla experienced insomnia, social withdrawal and persistent low mood. While initially resistant to relinquishing her desire for revenge, as she felt this meant letting her business partner off the hook, Marla was persuaded that it was she herself that was caught on the hook. She agreed to try Enright’s structured forgiveness therapy, first acknowledging her anger and shame, then gradually developing empathy for her partner. She was able to reframe the situation within a broader context and ultimately practice emotional release. Over time, Marla’s anxiety diminished, her sleep improved, and she reported a renewed sense of agency and freedom.
Given the power of revenge fantasies, it is critical to ask: will revenge erase my loss? Will it enhance my wellbeing? Will it prevent recurrence of harm? Typically, the answer is no. Forgiveness, in contrast, frees energy for meaningful action, including at social and structural levels where such action is often crucial. Resentment in marginalised or oppressed communities cannot be reduced to intrapsychic dynamics alone; it reflects systemic injustices. Therefore, healing may require combining personal forgiveness with empowerment and collective action.
From a physiological standpoint, chronic bitterness keeps the nervous system on high alert. Conversely, forgiveness has measurable health benefits: it reduces cortisol levels, lowers blood pressure, strengthens immunity, and shifts neural activity toward prefrontal regulation, empathy networks, and sustained reward circuits. Neuroscience thus provides compelling evidence that forgiveness is not just a moral virtue but a biologically adaptive practice.
Despite the challenges, forgiveness aligns with wisdom traditions across cultures. Yet it requires more than decision; it demands grace, a capacity to release harm without condoning it. It does not mean allowing injuries to persist, but it allows individuals to reclaim freedom, power and resilience. By confronting internalised shame, cultivating empathy, and integrating moral reflection, individuals can move from the destructive cycles of revenge toward enduring freedom, health, and meaningful connection.
*Marla is a fictitious amalgam to exemplify many similar cases that we see. The therapist is a fictional amalgam of both authors
Prof Gill Straker and Dr Jacqui Winship are co-authors of The Talking Cure. Straker also appears on the podcast Three Associating in which relational psychotherapists explore their blind spots
