Modern trends in pharmacopsychiatry最新文献

The concept of neuroprogression describes the progressive course of the disorder and stresses the progressive, recurrent, and chronic course of the disease entity under consideration. It subsumes clinical manifestations of the disease process and may also entail morphological, biochemical, neurochemical, immunological, physiological, and genetic aspects that contribute to the progressive course of the disease in question. In an attempt to identify the appropriate agent or method that could arrest neuroprogression in psychiatric patients, we conducted an evaluation of the use of anti-inflammatory drugs under the perspective of current pharmacological and neurophysiological data. This evaluation included the use of nonsteroidal anti-inflammatory drugs (NSAIDs) as adjunctive treatment to conventional pharmacotherapy as well as the use of natural products exerting anti-inflammatory properties (i.e., ω-3 fatty acids) given as adjunctive or monotherapeutic treatments in less severe cases. The therapeutic significance of nonpharmacological methods, such as psychotherapy, physical exercise, and body-mind therapies, was also considered and will be discussed in this chapter. In conclusion, the role of psychotropic and select anti-inflammatory drugs in arresting neuroprogression is a very promising new frontier in psychiatric research and clinical practice. Modulators of a specific prostanoid synthase or receptor across the cyclooxygenase (COX)-2 downstream pathway along with new multitarget NSAIDs are expected to be tested by the pharmaceutical industry as potential agents to antagonize neuroprogression. Meanwhile, salicylates and selective COX-2 inhibitors could still be used in carefully selected subgroups of patients. Psychotherapy and nonpharmacological, stress-relieving methods should be considered as adjunctive tools to aid in arresting neuroprogression.

Epidemiological studies implicate chronic depression as a predisposing factor for dementia in later life. However, the link is incompletely understood and controversial. The aim of this review is to consider some of the biological factors that contribute to neuroprogressive brain dysfunction in late life as a consequence of prolonged, low-grade inflammation in the course of depressive episodes. As chronic inflammation is known to precipitate increased apoptosis of neurons and astrocytes, this could be a contributing factor to brain dysfunction. In addition, certain proinflammatory cytokines activate the neurotoxic derivatives of the tryptophan-kynurenine pathway. This results in the synthesis of the NMDA glutamate agonist, quinolinic acid, and kynurenine metabolites which initiate oxidative stress and insulin receptor resistance. As a consequence of these changes, combined with a structural and functional defect in brain mitochondria, glucose transport into the brain is affected. Due to the ensuing reduction in the metabolic energy needed to sustain brain function, brain cells die prematurely. These changes could provide a link between chronic inflammation and dementia, at least in some patients with recurrent and chronic depression. This outcome may be particularly true in poor responders and treatment-resistant depression.

Neuropathic pain occurs as a result of lesion or disease affecting the somatosensory nervous system and is present in a diverse set of peripheral and central pathologies such as nerve trauma, diabetic neuropathy, post-herpetic neuralgia, chemotherapy-induced peripheral neuropathy, spinal cord injury and multiple sclerosis. Debilitating symptoms including allodynia, hyperalgesia and spontaneous pain have a substantial negative impact on patients' quality of life. The currently available therapeutic treatments are generally ineffective and characterised by poor response rates. Accumulating evidence suggests that neuroinflammation and cytokine signalling play a critical role in neuropathic pain. Numerous experimental studies have demonstrated that certain pro-inflammatory cytokines are elevated in neuropathic pain conditions, and administration of these cytokines can elicit pain hypersensitivity in the absence of injury or disease. This phenomenon is also apparent in the 'sickness response', which encompasses a broad inflammatory response to disease and injury and involves a series of physiological and behavioural changes including pain hypersensitivity. Interestingly, the 'sickness response' is also similar in nature to some of the defining characteristics of the depressed state of affective disorder. In this review, we explore links that may relate the co-existence of depression in neuropathic pain patients with the activity of cytokines and discuss the role of several key pro-inflammatory and anti-inflammatory cytokines in neuropathic pain.

Multiple emotional and cognitive factors impact on the experience of pain. This chapter will review some of the most important emotional and cognitive determinants of the pain experience as found in experimental and clinical studies with human participants. Emotional factors that may increase pain perception are anxiety, depression and anger. Positive emotions usually decrease perceived pain. The cognitive factors attention, expectancy and appraisal can either increase or decrease pain experiences depending on their specific focus and content. Many brain regions are involved in nociceptive processing and bringing pain into awareness. There are profound interconnections between areas processing sensory, emotional and cognitive information. Descending pathways from cortical areas to the midbrain and spinal levels can facilitate or inhibit spinal nociceptive information and thereby afferent nociceptive input to the brain. The underlying mechanisms of the various emotional and cognitive modulatory influences may partly overlap, but also have some unique aspects. What becomes clear is that pain is not merely a reflection of the nociceptive input, but should be considered as a complex experience shaped by psychological factors that may be unique for each individual.

Depression and chronic pain have been estimated to co-occur in up to 80% of patients suffering from these disorders, with this co-morbidity being more disabling and more expensive to both patients and society than either disorder alone. A number of neural substrates have been proposed to underlie this association; however, there has been increased interest and support for a role of neuroimmune and neuroinflammatory mechanisms as key players in this dyad. This chapter will provide an overview of the clinical and preclinical data supporting a role for neuroimmune alterations in depression-pain co-morbidity. We propose that such changes may impact on the functioning of key brain regions modulating emotional and nociceptive processing, thus resulting in the behavioural, psychological and physical symptoms observed in patients exhibiting depression and co-morbid pain.

Animal models of chronic pain have provided valuable information on the mechanisms of initiation and maintenance of the disease. Much of the research effort has targeted sensory abnormalities like hyperalgesia and allodynia. However, in the past 15 years a significant number of research groups have focused their attention on comorbid anxiety, depression and cognitive impairments that frequently emerge in chronic pain conditions. A myriad of paradigms have since then been introduced in the field to tackle multiple dimensions of rodents' behavior. Concerning emotional behavior, these include the elevated plus (and zero) maze and dark/light box for anxiety, the forced swimming and tail suspension tests for depression, and the spontaneous burrowing behavior for general well-being. Regarding the cognitive dimension, several water mazes (spatial-reference memory), attentional set-shifting test (attention and reversal learning), novel object recognition (memory), 5-choice serial reaction time task (sustained attention) and variable delay-to-signal task (impulsivity) are among the most commonly employed paradigms. The construct of some of these paradigms in the context of chronic pain will be reviewed in this chapter, with special emphasis on mood and cognitive alterations that are associated with the development of neuropathic and arthritic pain.

The neurophysiological link between neuropathic pain and depression remains unknown despite evident high comorbidity of these two disorders. However, there is convincing evidence that genotype plays a role in both pain and depression. Using various types of genetic analysis - population genetics, cytogenetics and molecular technologies - specific genes have been implicated in mediating almost all aspects of nociception and mood disorders. The current review attempts to identify specific genes and epigenetic mechanisms common to both disorders. It is concluded that external and internal factors (inflammation, stress, gender, etc.) that contribute to the pathologies may do so through epigenetic mechanisms that may affect expression of these particular genes. The possible involvement of epigenetic regulation in pain and psychiatric disorders suggests that treatments targeting epigenetic mechanisms that mediate adverse life events should be considered.

Co-morbid depression and chronic pain are highly prevalent. The purpose of this review is to examine the role of chronic inflammation as a common mediator of these co-morbidities. Dysfunctional bidirectional pathways between the brain and the immune, endocrine and neurotransmitter systems have been extensively described and implicated in pain and psychiatric disorders. This short review therefore accesses the evidence in favour of the psychoneuroendocrine hypothesis of psychiatric disorders under three main headings: (1) by illustrating how different types of stress play a crucial role in initiating chronic inflammation in major depression, (2) by accessing the evidence that pain is frequently an important component of, and an initiator of, depression, and (3) considering the evidence that chronic inflammation provides an important link between chronic pain and depression, and the possible cellular mechanisms involved in this process. By understanding the critical role that chronic inflammation plays in pain and depression, novel approaches to the development of drugs may emerge that offer improvements in treatment.

The transient receptor potential subfamily V member 1 (TRPV1) belongs to the diverse transient receptor potential (TRP) family of cation channels. It was first characterized in primary afferent fibres as a receptor for capsaicin. Peripheral TRPV1 has a very well-described role in nociception. However, TRPV1 is now recognized to have a broader distribution and function, with supraspinal/brain TRPV1 known to modulate pain processing. Recently, studies employing histological, genetic and pharmacological approaches have provided evidence that supraspinal TRPV1 also modulates brain neurobiology and behaviours related to anxiety, depression and schizophrenia. Key brain regions involved in TRPV1-mediated modulation of pain and affect include the periaqueductal grey, hippocampus and medial prefrontal cortex. Thus, TRPV1 in the brain is emerging as an important molecular substrate which is dually implicated in both pain and psychiatric disorders, and represents a novel therapeutic target for these conditions and their comorbidity.

The high comorbidity existing between visceral pain and psychiatric disorders such as depression and anxiety is well documented and it is gaining increasing interest among scientists. When visceral pain and psychiatric disorders are comorbid, they present a more debilitating condition than each disorder alone, impacting significantly on the quality of life of these patients. Despite several groups having shown that an overlapping pathophysiology exists between visceral pain and stress-related disorders the link between them is not clear yet. Moreover, it still remains to be elucidated if psychiatric conditions predispose the individual to develop visceral hypersensitivity or vice versa. The brain-gut-microbiome axis is the bidirectional communication between the CNS and the gastrointestinal tract. Alterations at different levels of this axis have been implicated in both visceral hypersensitivity and psychiatric disorders. Here we give an overview of what it is known about comorbid visceral pain and psychiatric disorders and provide evidence of potential overlapping pathophysiological mechanisms involved. Preclinical models of comorbid visceral pain and stress-related disorders are also discussed.