Introduction: The perception of temperature (i.e., thermosensation) has traditionally been classified as a submodality of exteroception. However, although this modality is the results of stimulation on the body surface, thermosensation also carries information about the physiological state of the skin and the body, often referred to as interoception¹. Interoception is crucial for our survival but also for the experience of emotions and mental health. Crucially, the body and brain are both involved in thermoregulation processes, such as sweating or shivering², and these bodily functions are also closely linked to the experience of emotions such as stress and fear.

Objectives: Although the relationship between changes in body temperature and the experience of emotions has received increasing attention, less is known about the relationship between individual differences in the perception of thermal changes on the body and affective symptoms. Accordingly, here, we focused on the relationship between self-reported depression, anxiety, and stress and thermosensation.

Method: One hundred seventy healthy participants (87 females, mean age 26.297 ± 5.05 years) completed the Depression Anxiety Stress Scale (DASS-21)³ and a dynamic thermal matching task⁴ on hairy (i.e., forearm) and non-hairy skin (i.e., palm). Thermal stimuli were delivered using a thermode attached to a thermal stimulator. The participants’ skin was stroked at reference temperatures of 30°C, 32°C or 34°C, and the task consisted of verbally indicating when they felt the same reference temperature again. The task followed a staircase procedure, that is, the temperature was either increased or decreased towards the reference temperature in discrete steps of 2°C. Participants also completed two control tasks: the heartbeat counting task, to measure cardiac interoception, and a classic temperature detection task. The study was conducted in accordance with the provisions of the 1975 Declaration of Helsinki, as revised in 2008. 

Results: Our results revealed that higher self-reported anxiety was related to a better performance on the thermal matching task on the forearm (rho = 0.167, p = 0.028), while higher depression was related to poorer performance on dynamic and static temperature tasks on the palm (rho = -0.188, p = 0.014). Discrepancies between thermosensory accuracy and sensibility measures (‘trait prediction error’) were related to heightened anxiety (rho = -0.224, p = 0.003), in line with previous studies suggesting that alignments of interoceptive dimensions (i.e., accuracy, sensibility, awareness) can predict emotional symptoms, such as anxiety⁵. No significant correlations were found between DASS-21 scores and heartbeat counting accuracy nor between DASS-21 and static thermosensation.

Conclusion: This study suggests that individual differences in thermosensory perception in different areas of the body are associated with self-reported anxiety and depression. Taken together, the present work supports a link between skin-based interoception, specifically thermosensation, and emotions and mental health. As such, the current findings can pave the way for further investigations on the use of thermal imaging as a potential measure of emotional arousal and anxiety. Such insight can shed light on conditions characterized by disorders in the experience of emotions such as alexithymia, which is also characterized by deficits in interoception and thermosensation.