Psychiatric Aspects of Infections
José Luis Ayuso-Mateos
Neuropsychiatric disturbances stemming from infectious diseases are widespread in both the industrialized world and developing countries. Such neuropsychiatric syndromes are not necessarily the result of infectious processes directly involving the central nervous system, they may also be complications of systemic infections. There are many microbial, viral, and parasitic agents, as well as other types of infectious substances, which can affect the central nervous system, leading to the appearance of neurological and psychiatric symptoms that may cause suffering to the patient, and even be disabling.
When considering the psychiatric manifestations of infectious illness, it is important to consider clinical manifestations derived
from a possible systemic infection, which can be less obvious than a direct involvement of the central nervous system. Acute organic reactions may accompany many systemic infections, especially at the extremes of life. A clear example is the delirium that frequently occurs with pneumonia in the elderly. In these clinical syndromes, several factors could be responsible for the alterations in cerebral metabolism. The mere fact of having a fever could be involved. Cerebral anoxia often appears to be responsible, or the influence of toxins derived from the infecting micro-organism. More complex metabolic disturbances or the accumulation of toxic intermediate products can also be implicated.
from a possible systemic infection, which can be less obvious than a direct involvement of the central nervous system. Acute organic reactions may accompany many systemic infections, especially at the extremes of life. A clear example is the delirium that frequently occurs with pneumonia in the elderly. In these clinical syndromes, several factors could be responsible for the alterations in cerebral metabolism. The mere fact of having a fever could be involved. Cerebral anoxia often appears to be responsible, or the influence of toxins derived from the infecting micro-organism. More complex metabolic disturbances or the accumulation of toxic intermediate products can also be implicated.
Likewise, infections that course as chronic or subacute illnesses are frequently accompanied by the onset of depressive syndromes. One of the factors implied in clinical depression that occurs within the context of systemic infectious illnesses (e.g. tuberculosis and infectious mononucleosis), is a sense of physical vulnerability, possibly heightened by a loss of strength and negative changes in the patient’s appearance. Patients are often afraid of losing their earning capacity or even their jobs, as well as other social and occupational problems associated with the illness.
Another very important factor, above all with the human immunodeficiency virus (HIV) and other sexually transmitted disease (STD), is the social stigma that these patients may suffer.(1) Sexually transmitted disease infection implies sexual activity that historically carries connotations of illicit, casual, sexual encounters, and acquiring an STD is frequently associated with embarrassment and social stigma.
In addition to the disease itself, the medications commonly used to treat infectious illnesses can have side-effects that alter patients’ behaviour, as well as their cognitive and affective functioning (Table 5.3.5.1).
In this chapter we consider infections of clinical interest in the practice of psychiatry. These conditions will be dealt with briefly, and textbooks of general medicine should be consulted for further details. Prion diseases and chronic fatigue syndromes, which are also related to the subject of the present chapter, are discussed in Chapters 4.1.4 and 5.2.7, respectively.
HIV infection
Patients infected with HIV are at an increased risk for a variety of mental disorders. Those encountered most frequently in psychiatric practice are discussed below. HIV dementia is discussed in Chapter 4.1.9.
Nature of neuropsychiatric disorders in HIV-infected patients
Neuropsychiatric disorders are common in HIV-infected patients, and they can be either primary or secondary. Primary complications are those that can be attributed directly to the infection of the central nervous system by the virus, or to immunopathological events precipitated by HIV infection. Primary HIV-related brain disorders include HIV-related dementia and minor cognitive disorder.(2) Immune suppression can lead to a variety of secondary complications affecting the brain, including opportunistic infections (e.g. cerebral toxoplasmosis and progressive multifocal leucoencephalopathy) and tumours (e.g. cerebral lymphoma). Secondary complications in the form of acute and subacute syndromes (e.g. delirium) often occur as a result of cerebrovascular complications and toxic states induced by various therapeutic agents.
Table 5.3.5.1 Neuropsychiatric adverse effects of drugs frequently used in the treatment of infectious diseases | ||||||||||||||||||||||||||||||||||||||||
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HIV-associated acute stress reaction
This transitory syndrome appears in some individuals after they are notified of their seropositivity. It is equally frequent among those who, after a period as an asymptomatic carrier, are informed that the infection has progressed towards full-blown AIDS. The appearance of these symptoms is closely linked in time to the stressful circumstance, and generally remits in hours or days.
The symptoms are highly varied. Some patients suffer from intrusive thoughts or brooding related to their uncertainties regarding health, the future, the risk of contagion to others (especially loved ones), and the idea of death. The vegetative symptoms of panic attacks are also usually present. In more severe cases, the patient may also present social isolation, verbal expressions of rage or feelings of desperation, and other forms of altered behaviour.
Depression
(a) Clinical features
Depression is one of the most common psychiatric disorders found among HIV-infected individuals. Symptomatic stages of HIV infection are associated with an increased prevalence of depressive symptoms and a syndromal diagnosis of major depression.(3)
There are several factors behind the increased morbidity for affective disorders found in this population. First of all, the patient’s discovery of the infection has a dramatic psychological impact, as does the disease’s relentless progression. Second, the neurotropism of the virus itself produces neuropathological changes in deep grey structures whose dysfunction is known to cause mood disturbances and changes in the neurotransmission systems, which may contribute to the development of depression. Finally, the groups that in Western countries are at the highest risk for HIV infection (intravenous drug users and male homosexuals/bisexuals) are also known to be at a high risk for depressive syndromes, independently of having the virus. The risk factors for depression appear to be similar to those for HIV-seronegative patients and include, besides advanced HIV infection: loss of social support; personal and family history of depression; drug use; and lack of confidants.
When severe physical disease is present the diagnosis of major depression can be difficult to make, because the disease itself may be the real source of many depressive symptoms, for example insomnia, loss of appetite and weight, fatigue, lack of energy, retardation, and concentration difficulties. To avoid misdiagnosing depression, it is important to focus on the more psychological, as opposed to somatic, symptoms associated with low mood. These include persistent low mood, loss of enjoyment of usually pleasurable activities, suicidal thoughts and marked feelings of hopelessness, guilt, and self-reproach. Suicidal ideation may not be expressed directly, but may be expressed more passively, for example poor adherence to medical treatment. Assessment of depressed mood also requires evaluation of the probable contributing factors.
(b) Management
(i) Pharmacological treatment
Antidepressants are the treatment of choice in major depression, as well as in less severe depressive syndromes that are unresponsive to psychological and social intervention. Tricyclic antidepressants have been shown to be effective in treating depressed HIV-positive patients.(4) AIDS patients can respond to lower dosages of tricyclics (25–100 mg), but they may also suffer severe anticholinergic effects at reduced dosages. Therefore, the choice of an antidepressant for these patients should be guided by its side-effect profile.
Several studies have been published showing therapeutic response to selective serotonin reuptake inhibitors in seropositive patients with major depression.(5) Many clinicians prefer the newer drugs in the medically ill, not only because of their higher acceptance among patients, but also because of their greater overdose safety margin.
(ii) Psychotherapy
Psychosocial interventions derived from a wide variety of theoretical orientations are effective in treating depression among individuals infected with HIV. There is good evidence for the value of psychological intervention in the management of HIV patients. Both interpersonal psychotherapy(6) and cognitive–behavioural group therapy(7) may be particularly beneficial for HIV patients with depressive symptoms.
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