Human suffering is one of the most complex and difficult realities to define in contemporary medical and bioethical practice. Beyond physical pain, it includes emotional, existential, and social dimensions that defy any attempt at objective measurement. This article analyzes the multidimensional nature of suffering, its relevance in the clinical and legal context—especially after the legalization of euthanasia in Spain—and the ethical difficulties involved in determining when a condition can be considered intolerable or irreversible.

In contemporary clinical practice, few concepts are as crucial and, at the same time, as elusive as that of suffering. Despite its centrality in medicine, particularly in the areas of serious illness, chronicity, and end-of-life care, the literature reveals a remarkable lack of classification. This deficiency is not merely academic: it has direct consequences for clinical, ethical, and legal decision-making.

In Spain, Organic Law 3/2021 regulating euthanasia introduces a particularly relevant element. In the two grounds for requesting it, the existence of “intolerable suffering” is listed as a criterion. This seemingly clear formulation presents significant difficulties: How is suffering measured? What type of suffering is being considered? Under what criteria can it be classified as intolerable or irreversible?

The first problem is conceptual. As the American physician Eric J. Cassell already pointed out, suffering is not exclusively identified with physical pain, nor is it limited to it; rather, it constitutes a perceived threat to the integrity of the person as a whole. From this stems a crucial assertion: it is not bodies that suffer, but people. This idea compels us to abandon any attempt to reduce suffering to purely biological parameters and to recognize its radically impersonal nature.

However, this conceptual expansion introduces a second difficulty: it is a subjective experience. Unlike other clinical parameters (a laboratory result or an imaging test), it cannot be directly quantified. It can only be reported by the person experiencing it. And what constitutes a source of suffering for one person may not be so for another. This subjectivity makes its clinical assessment indirect and mediated by interpretation.

The three dimensions of suffering

Given this complexity, it is essential to move towards a classification, even if only of an operational nature. From an integrative medical perspective, at least three relevant dimensions of suffering can be distinguished:

• Organic . This stems from measurable physical alterations: pain, shortness of breath, chronic fatigue, etc. It has an identifiable biological basis and, in principle, is amenable to therapeutic intervention. However, the relationship between injury and suffering is complex: pain does not always generate proportional suffering, and not all suffering is due to organic damage.
• Emotional or psychological . Linked to affective states such as anxiety, depression, fear, and guilt. This type of suffering can coexist with an organic disease or occur relatively independently. Its relevance is undeniable in contexts such as the diagnosis of a serious illness and the loss of autonomy.
• Existential or spiritual . This is probably the most difficult to study. It refers to the perception of a loss of meaning, identity, or dignity. It appears paradigmatically in situations of advanced illness, dependency, or extreme vulnerability. It reminds us that human beings are, in essence, Homo patiens.

To these dimensions we must add other complementary ones. For example, social suffering, stemming from isolation or loss of role. Or moral suffering, associated with conflicts of values. Together, these forms constitute a multidimensional experience that cannot be fragmented without impoverishing its understanding.

The invisible suffering

It is also worth emphasizing that suffering is not limited to classic clinical settings. It is present in many human situations, many of them invisible or insufficiently recognized.

A relevant example is suicide. In Spain, according to official data, 3,953 deaths were recorded from this cause in 2024. This figure alone reveals that suffering, especially of a psychological nature, is a much broader, deeper, and more widespread phenomenon than is often acknowledged in public discourse.

The suffering that leads to suicide is not always visible or easily objective, but its reality is unquestionable.

Treatable or irreversible?

Another problem is the difficulty in differentiating between treatable suffering and suffering considered irreversible.

From a clinical perspective, irreversibility is usually associated with the progression of a disease or the lack of effective therapeutic alternatives. However, when suffering is psychological or existential in nature, this category becomes extraordinarily uncertain. Clinical history shows that experiences of intense suffering can be modified over time through therapeutic intervention, support, or life changes.

Finally, the suffering associated with mental illness deserves specific attention. It is a unique form of suffering, characterized by its intensity and, at times, by the difficulty in communicating it. Furthermore, it is frequently met with suspicion or social underestimation, which adds an extra burden to the suffering itself.

Ultimately, human suffering is not a readily measurable quantity, but a complex, multidimensional, and profoundly personal experience. Medicine must resist the temptation to oversimplify it. The law, when using it as a decisive criterion, must do so with full awareness of its limitations. For where we attempt to measure, suffering reminds us that understanding remains, ultimately, the essential task.

José María Domínguez. President of the Ethics and Professional Conduct Committee of the Spanish Medical Association. Member of the Bioethics Observatory. Institute of Life Sciences. Catholic University of Valencia