Functions Of Diagnostics

It is generally accepted that medical diagnosis should be directly related to scientifically demonstrated underlying pathophysiological processes. Thus all medical diagnostics, including those in psychiatry, should eventually be assisted by biological measures. This has barely started to happen in modern psychiatry (Chapters 6 and 7).

We should recall that medical diagnostics have three major functions: (1) At the lowest level, they are designed to allow clinicians some assurance that they are talking about the same problems (DSM-IV fulfills that nicely). (2) They provide an efficient way to promote consistent therapeutic approaches (e.g., a short-hand path to prescription practices). (3) Also, they provide a rapid way to think about the etiology of disorders. Perhaps the take-home message of this last function should be that we must reach a better understanding of the basic emotional systems of the brain, especially as they contribute to both psychiatric disease and health. Of course, this is based on the assumption that most psychiatric disorders ultimately reflect disturbances of affect-generating processes of the brain, a position that remains controversial among both psychiatrists and psychologists. Indeed, for the cognitive disorders of schizophrenia (Chapter 9) and some of the pervasive developmental disorders of childhood (Chapter 14), this may seem unlikely, even though changes in emotionality are surely contributory factors.

This third function of diagnostics relates directly to issues of pathophysiology and pathogenesis. With the emergence of an understanding of brain transmitter systems in the 1960s, there arose great hopes that imbalances in one or another system would map well onto psychiatric disorders. Schildkraut (1965) made the seminal suggestion that depression may arise from biogenic amine deficiencies, and norepinephrine depletion was suspected to be the major culprit. Unfortunately, the hope that different types of depression might be diagnosed by patterns of cerebrospinal amine metabolites never cashed out. However, at least one instance did bear fruit: The onset of manic episodes does correspond rather well to hyperarousal of brain norepinephrine systems (Garlow et al., 1999).

Likewise, there was optimism that certain forms of schizophrenia would ultimately reflect a variety of possible disruptions of metabolic pathways that would lead to the excessive synthesis of catechol- or indoleamine-like hallucinogens. The many fascinating hypotheses that were generated eventually led to no consensus concerning the role of such factors. Still, these ideas are open territory for further developments. A classic psychosis can be generated by imbalancing glutamate activity in the brain with the phencyclidine hallucinogens. Thus, it is still generally agreed that schizophrenia is closely linked to imbalanced activities of certain brain dopamine systems, in concert with various other neurochemistries (Carlsson et al., 2001) and that anxiety is intimately related to the activity of GABA along FEAR systems (Chapter 16).

As far as neuroscience is concerned, there have been spectacular advances in our knowledge of the molecules that will eventually be relevant for understanding psychiatric disorders (Charney et al., 1999) but much less enthusiasm for linking such entities to mental functions. Likewise ongoing attempts to link psychiatric disorders with specific brain systems has been criticized in recent years. Valenstein (1998) provides one provocative historical overview of the many attempts and failures. He emphasized how modest real progress has been and how, "in the absence of a coherent understanding of the pathological basis of a disease, only serendipity can provide effective drugs for its treatment. Nowhere is this more evident than in an examination of the history of psychotherapeutic drugs" (quote by Sneader, 1990, in Valenstein, 1998 p. 9). But his thesis has not gone unchallenged by leaders of the biological psychiatry community (for a debate, see Valenstein and Charney, 2000). It is now generally accepted that there is much more to psychiatric disorders than neurochemical imbalances, and with recent technological advances, the neurobiological search has shifted substantially to anatomical and genetic underpinnings.

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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