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Journal of Clinical and
Basic Psychosomatics Psychosomatic influences on insomnia

nucleus and brainstem arousal systems. 16-22 Disruptions in the SWC. In response to stress, the hypothalamus releases
orexin signaling are linked to insomnia, where heightened corticotropin-releasing hormone, which stimulates the
arousal and vigilance hinder the ability to transition into pituitary gland to secrete adrenocorticotropic hormone
and maintain sleep. 22-26 (ACTH). ACTH then triggers the adrenal glands to
In addition to circadian rhythms, the homeostatic sleep produce cortisol (Figure 1). Under normal conditions,
drive, which builds up during wakefulness, plays a critical cortisol levels follow a diurnal rhythm, peaking in the early
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role in sleep regulation. Adenosine, a neuromodulator, morning and gradually declining throughout the day.
accumulates during wakefulness and promotes sleep as However, chronic stress and emotional disturbances
its levels rise. Disruptions in adenosine signaling can can lead to HPA axis dysregulation, characterized by
contribute to difficulties falling asleep and maintaining elevated cortisol levels, particularly in the evening, when
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restful sleep, which are hallmarks of insomnia. 27,28,33 they should be at their lowest. This abnormal cortisol
Molecular disruptions affecting circadian rhythms, secretion disrupts the SWC, contributing to difficulties in
homeostatic drive, and neurotransmitter systems, such falling asleep and maintaining sleep. Elevated cortisol levels
as orexin, exacerbate insomnia by increasing arousal and are also associated with increased nighttime awakenings
reducing sleep efficiency. 29-35 and lighter, less restorative sleep. The persistent activation
of the HPA axis in response to stress not only perpetuates
The aim of this review is to provide a comprehensive insomnia but also exacerbates the psychological factors,
analysis of psychosomatic influences on insomnia, such as anxiety and hyperarousal, that contribute to the
examining the neurobiological, psychological, and somatic disorder. 42
mechanisms involved. The review also explores diagnostic
challenges and proposes integrative treatment strategies to 2.1.2. Neurotransmitter imbalances
address both the physical and mental aspects of insomnia, Neurotransmitters play a crucial role in regulating
contributing to a holistic understanding and management of mood, arousal, and sleep. Imbalances in these chemical
the disorder. This review uniquely focuses on the interaction messengers are closely linked to both psychological states
between neurobiological mechanisms (e.g., hypothalamic– and sleep disturbances. Serotonin, gamma-aminobutyric
pituitary–adrenal [HPA] axis dysregulation) and acid (GABA), norepinephrine, histamine, and glutamate
psychological factors (e.g., emotional dysregulation), a topic are particularly important in the context of insomnia.
less explored in earlier research. In addition, it emphasizes
integrative treatment approaches such as mindfulness and Serotonin is involved in mood regulation, and its
lifestyle modifications alongside traditional methods, while deficiency is associated with depression and anxiety, both
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highlighting the importance of personalized treatment of which are common in individuals with insomnia.
strategies tailored to individual patient profiles. Finally, it Serotonin is also a precursor to melatonin, a hormone that
delves into the underexplored bidirectional relationship regulates the SWC. Reduced serotonin levels can lead to
between chronic medical conditions and insomnia, impaired melatonin production, disrupting sleep onset and
offering new insights into the complexity of this disorder. quality. GABA is the primary inhibitory neurotransmitter
in the brain, promoting relaxation and reducing neuronal
2. Mechanisms of psychosomatic influences excitability. In individuals with insomnia, GABAergic
on insomnia activity is often diminished, leading to increased arousal
and difficulty in initiating sleep. This reduction in GABA
2.1. Neurobiological mechanisms activity is thought to be linked to stress and anxiety,
The neurobiological mechanisms underlying psychosomatic further contributing to insomnia. Norepinephrine is
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influences on insomnia involve a complex interaction associated with the body’s fight-or-flight response and
between the central nervous system, neuroendocrine is typically elevated during periods of stress. Increased
pathways, and the body’s physiological responses to stress. norepinephrine levels can lead to heightened arousal
These mechanisms not only contribute to the onset of and vigilance, making it difficult to relax and fall asleep.
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insomnia but also play a crucial role in its persistence, Chronic elevation of norepinephrine due to stress can
especially in the presence of psychological stressors and also disrupt rapid eye movement (REM) sleep, leading
emotional dysregulation. to fragmented and less restorative sleep (Figure 2). 46,47
Histamine plays a dual role in sleep regulation; whereas
2.1.1. Dysregulation of HPA axis it is involved in promoting wakefulness through its action
The HPA axis is a central component of the body’s stress in the hypothalamus, elevated levels of histamine can lead
response system, which is responsible for regulating the to insomnia and sleep disturbances. Histamine release
release of cortisol, a hormone that plays a critical role in is often increased during stress responses, contributing

Volume 3 Issue 1 (2025) 34 doi: 10.36922/jcbp.4588