Prevalence Of Psychological Changes In Neurological Patients

Psychological function can be altered in diverse ways after brain damage or disease. Here we will focus on several studies that discuss the incidence of such psychological changes. Psychiatric changes are common after focal brain disease and brain injury. For example, a number of studies have investigated the consequences of traumatic brain injury, where depression appears to be the most prevalent psychiatric outcome. Recent studies have estimated that clinical depression affects a majority of traumatic brain injury sufferers in the period immediately after their brain injury (e.g., Deb et al., 2000; Silver et al., 1991; see Hales and Yudofsky, 1997, for review). At 12 months postinjury clinical depression was still prevalent in some 20 percent of patients (Deb et al., 2000; Fedoroff et al., 1992), frequently persisting beyond 24 months (Rao and Lyketsos, 2000). Similarly, anxiety disorders, including posttraumatic stress disorder and obsessive-compulsive disorder, are common after traumatic brain injury (Jorge, 1993; Kant et al., 1996; Van Reekum et al., 2000), as are a range of psychotic disorders (Hales and Yudofsky, 1997, pp. 532-533). Indeed, a conflation of the effects of traumatic brain injury and psychosis has led to some confusion in the literature, so that studies have demonstrated disorders classified as psychosis, schizophrenia, and schizo-affective disorder in patients whose major explicit problem has been traumatic brain injury (e.g., Wilcox and Nasrallah, 1987; see Hales and Yudofsky, 1997, for further cases). Unfortunately, such studies focus more on epidemiology than neuropsychol-ogy, so that traumatic brain injury (to take one instance of pathology) is viewed as a unitary pathological category. In practice, several brain regions are routinely damaged in closed-head injury: the orbital frontal lobes, the anterior temporal lobes, and the upper brainstem all may be involved. In addition, there are frequent lesions to regions that are quite inconsistent across cases, making this pathology notoriously unreliable for the purposes of clinical-anatomical correlation (Kertesz, 1983). Epidemiological studies typically fail to investigate the consequences of lesion to specific brain regions, much less the particular psychological mechanisms, which contribute to the psychiatric changes in each case.

Such studies do little justice to our current understanding of the way in which psychological functions are organized within the brain. Why are these patients depressed, anxious, and psychotic after their brain injury? Is it a simple consequence of well-understood cognitive deficits sustained in the accident? For example, are they depressed because they are now amnesic or aphasic? Could it even be a consequence of peripheral (i.e., nonbrain) injuries to the body, as anyone might become depressed following a brachial plexus lesion or facial scarring after a motor vehicle accident? When one systematically investigates the effects of focal brain lesions, it becomes clear that specific sorts of psychological change reliably follow from particular lesion sites. For those working in cognitive neuropsychology (and cognitive neuropsychiatry) it is of no consequence whether the lesion is caused by stroke, head injury, or tumour—providing it disrupts the brain region or psychological function of interest. Matters of epidemiology are also of no great concern, with scientists showing a clear preference for striking, or exceptionally pure, cases. As a result, the field has been dominated by single-case investigations or the multiple single-case approach (Caramazza, 1986; Shallice, 1988). It is from this tradition that the work in this chapter derives.

In our first example of depth neuropsychological changes, we briefly discuss one class of lesion site, that of disorders to the lateral surface of the left convexity, where patients suffer substantial cognitive deficits—primarily in the domain of language, though also extending to the domains of voluntary action and some classes of visuo-spatial ability. Such patients quite commonly also suffer a right hemiparesis. Their psychological response to such losses is of great interest. As one might expect from a situation in which individuals have lost a range of important abilities, they are often overcome with feelings of loss and are frequently depressed. However, they cope with these problems in precisely the same way that neurologically normal individuals would cope with them: that is, they gradually come to terms with their loss through a period of mourning. In the course of this process, they begin to rebuild a life that takes account of their new circumstances.

We discuss some cases of this sort at the beginning of this chapter because such reactions to brain damage or disease are not universally found in neurological patients, as will become clear in the later parts of this chapter, where one sees (for example) a denial of deficit, with the patient adopting a distorted view of his or her explicit circumstances (i.e., of reality). Such changes in the very fabric of the person appear to follow from lesion to parts of the brain that lie closer to the core of the personal-ity—probably because they impinge on systems centrally involved in the regulation of emotion and motivation (Solms and Turnbull, 2002).

Anxiety and Depression 101

Anxiety and Depression 101

Everything you ever wanted to know about. We have been discussing depression and anxiety and how different information that is out on the market only seems to target one particular cure for these two common conditions that seem to walk hand in hand.

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