Interoception and psychosomatic medicine (3): Emotion and body

Interoception is the sense of the internal state of the body.
“Emotions” and “affects” are functions that are fundamental to human psychological processes, such as joy, anger, sorrow, anxiety, tension, and pleasure/displeasure. These psychological processes of emotion and affect are closely related to the interoceptive sense that captures the internal state of the body. “Emotions are rooted in the body”. Let’s explore the important relationship between emotions and interoception in psychosomatic medicine.

Emotions and Affects

“Emotion” refers to processes of the mind, such as joy, anger, and sorrow. We experience various emotions in response to different events and situations in our daily lives.

Even in animals, there are various emotions such as being in a good or bad mood, but human emotions are more diverse and complex. More complex emotions are referred to as “higher-order” emotions, while “lower-order” emotions are more vague, such as pleasure/displeasure, and are sometimes distinguished from emotions and called “affects”.
[※ Terminology in this area varies among researchers, but this article follows the usage of Damasio and others.]

“Affect” is closely linked to physiological functions. For example, it is difficult to distinguish between physical discomfort → fatigue → depressive feelings as to how much is physiological discomfort and how much is psychological state. The same applies to physical tension → psychological tension or anxiety.

● Being “higher-order” implies being closer to a psychological level, and
● Being “lower-order” implies being closer to a physiological or bodily level,
is the image.

As it is said that “people do not act on reason but on emotion” or “people are emotional animals,” emotions are very important in our lives. Avoiding people who evoke unpleasant emotions when nearby can lead to avoiding danger. Emotions play a significant role in making important choices such as “where to live” or “which group to belong to.”

In addition, humans are social animals and possess a high level of sociability mediated by complex emotions (higher-order emotions). Communication is extremely important in social living, and emotions also play an important role in communication.

Thus, emotions and affects have a fundamental importance in human life, including behavior, judgment, decision-making, and communication.

Interoception as the Basis of Emotion

How does the bodily sensation of “interoception” relate to the psychological process of emotion? In recent years, there have been remarkable advances in neuroscience, and various mental functions have been elucidated in terms of which parts or networks of the brain are involved and how they are formed. It has been found that there is considerable overlap between the regions involved in emotion formation and those involved in interoceptive sensation. In particular, a region of the brain called the “insula” is said to play a central role in both.

Emotions experienced in various situations in daily life. What influences those emotions?.

First, external situations and contexts influence emotions. Positive emotions arise when praised by others, while negative emotions arise when criticized.

In addition, sensory information such as the five senses accompanying it also influences emotions. In a park surrounded by nature and a calm atmosphere, you are likely to feel good and positive emotions such as joy are more likely to arise, and the scent of trees and flowers (olfactory information) also induces positive emotions. Conversely, seeing or hearing unpleasant people’s voices or actions will evoke negative moods and emotions.

Another major factor is one’s internal bodily state. It is common for irritability and anxiety to occur more easily with the menstrual cycle in women. Even if the same thing is said by the same person, the emotions experienced vary greatly depending on whether one’s physical condition is good or bad. When physically fit, positive emotions are more likely to arise from a cheerful mood, whereas when physically unwell, mood also declines, making negative emotions more likely to arise.

In this way, while external situations and internal states largely influence emotions, it is also believed that emotions arise from sensory information at the level of sensation,
(1) sensory information from the external environment external interoception and
(2) sensory information from internal states internal interoception.
The integration of these external interoception and internal interoception is believed to occur in the aforementioned region of the brain called the insula.

While there are various opinions on distinguishing between external interoception and internal interoception, it can be said that strict differentiation is difficult. This is because internal states change depending on external situations, and the perception of external situations also changes depending on internal states, creating a mixed and integrated whole. Some perspectives include external interoception in internal interoception. Furthermore, emotions are strictly internal experiences, and they are only conveyed to others through words or expressions.

Taking all of these factors into consideration, it can be said that interoception serves as the basis for emotion formation.

The Body as the Basis of Emotion

With interoception as the foundation of the psychological process of emotion, the body is the basis of emotion = “the body is the basis of emotion”. What does this mean in psychosomatic medicine, psychosomatic internal medicine, and clinical medicine?

One important point is that since the body is fundamentally involved in emotions (and higher-level psychological processes), the assessment of bodily state is essential in mental health and emotion management, and regulation of interoception is key.

It has been said for a long time in the “stress society” that with the advent of post-corona and rapid advances in AI, the importance of stress management and mental health is increasing. However, focusing only on the psychological aspect in counseling, etc., may overlook the importance of physical conditions.

It is sometimes experienced in the medical practice of psychosomatic internal medicine that although psychological problems are thought to be the main issue and attention is focused on them, the condition does not improve easily, and it turns out that physical problems were overlooked.

For example, in the case of a middle-aged woman with symptoms such as depression or panic attacks, it was thought that psychological issues such as family relationships were largely involved, but in reality, there was an abnormality in female hormone levels and the influence of menopausal symptoms was significant. Once that improved, the psychological situation also became less problematic.

The Inseparable Connection between Mind and Body “Mind” and “Body”

Even if it doesn’t reach the level of physical illness, there are various fluctuations in physical condition. Since psychological states vary depending on whether one’s physical condition is good or bad, for mental health management = mental health, it is necessary to manage physical condition together. At the very least, awareness of the physical aspect is necessary.

Conversely, psychological problems can also affect physical condition. There are cases where psychological problems that the person is not aware of are behind prolonged physical symptoms such as pain, and despite undergoing various medical tests, no abnormalities are found, and treatments such as medication do not work. In such cases, improvement was achieved through psychological approaches.

When it is said that “the body is the basis of emotion,” it is easy to think of it as a one-way relationship from body to emotion (mind), but emotions also have an impact on the body. In fact, the internal interoception system is not only a centripetal (toward the central nervous system) function but also a centrifugal (from the central nervous system to the periphery) function, and it has been confirmed neuroscientifically that it is a bidirectional system.

Understanding the intimate relationship between “mind and body” is important. And if interoception becomes appropriate, it becomes easier to notice one’s own state, such as feeling tired, and early intervention becomes possible. This is the key to surviving the stress society and has significant implications for the treatment of stress-related disorders.

(Kanbara K, LABs Psychosomatic Medicine,, Oct 2023)

Related Columns, Articles, and Research

Kanbara, K., Fukunaga, M. Links among emotional awareness, somatic awareness and autonomic homeostatic processing. BioPsychoSocial Med 10, 16 (2016).