The Links Between Infections and Psychiatric Diseases
The Links Between Infections and Psychiatric Diseases
This article briefly reviews types of psychopathology that have been or can be etiologically related to infectious agents. Particular emphasis is placed on AIDS dementia, schizophrenia, chronic fatigue syndrome, bipolar disorder, and obsessive-compulsive disorder because these diseases are either best understood or intensely investigated with regard to infectious etiology. Ongoing research efforts aimed at identifying missing links between infections and psychiatric diseases are briefly described, illustrating current interests and efforts in this area of biomedical research.
Increasingly sensitive techniques for detection of nucleic acids have revealed that the central nervous system (CNS) is susceptible to infection to a degree higher than previously thought. Thus, latent (as opposed to productive) infections are now more easily detected than in the past and reveal the presence of neurotropic and neurovirulent pathogens. In most cases, these CNS infections result in nonspecific symptoms such as headache, meningeal signs, seizures, impairment of alertness, or delirium.
Some infectious agents, however, have a particular neurotropism and can cause specific psychopathology. In fact, a few psychiatric disorders have been etiologically related to certain infectious agents. Postulated pathogenic mechanisms range from direct neuronal damage to indirect neurotoxicity mediated through immunologic reactions or release of cytotoxins. In some cases, the infectious etiology has been suspected but not conclusively proven; in others, the infectious etiology has been documented, but the exact pathogenesis underlying neurobehavioral dysfunction remains to be clarified.
In this review, the main psychiatric disorders that have been definitively or putatively linked to specific infections are described and discussed (Table I, II). The emphasis is on (1) behavioral, cognitive, and psychiatric manifestations, rather than neurologic disorders, and (2) pathogenic links between infection and psychiatric symptomatology, rather than on treatment modalities. The diseases covered and the references listed are selective rather than exhaustive. The current status of basic science and recommendations for future research in neurovirology and neuroimmunology have been described elsewhere.
This article briefly reviews types of psychopathology that have been or can be etiologically related to infectious agents. Particular emphasis is placed on AIDS dementia, schizophrenia, chronic fatigue syndrome, bipolar disorder, and obsessive-compulsive disorder because these diseases are either best understood or intensely investigated with regard to infectious etiology. Ongoing research efforts aimed at identifying missing links between infections and psychiatric diseases are briefly described, illustrating current interests and efforts in this area of biomedical research.
Increasingly sensitive techniques for detection of nucleic acids have revealed that the central nervous system (CNS) is susceptible to infection to a degree higher than previously thought. Thus, latent (as opposed to productive) infections are now more easily detected than in the past and reveal the presence of neurotropic and neurovirulent pathogens. In most cases, these CNS infections result in nonspecific symptoms such as headache, meningeal signs, seizures, impairment of alertness, or delirium.
Some infectious agents, however, have a particular neurotropism and can cause specific psychopathology. In fact, a few psychiatric disorders have been etiologically related to certain infectious agents. Postulated pathogenic mechanisms range from direct neuronal damage to indirect neurotoxicity mediated through immunologic reactions or release of cytotoxins. In some cases, the infectious etiology has been suspected but not conclusively proven; in others, the infectious etiology has been documented, but the exact pathogenesis underlying neurobehavioral dysfunction remains to be clarified.
In this review, the main psychiatric disorders that have been definitively or putatively linked to specific infections are described and discussed (Table I, II). The emphasis is on (1) behavioral, cognitive, and psychiatric manifestations, rather than neurologic disorders, and (2) pathogenic links between infection and psychiatric symptomatology, rather than on treatment modalities. The diseases covered and the references listed are selective rather than exhaustive. The current status of basic science and recommendations for future research in neurovirology and neuroimmunology have been described elsewhere.
