Nancy C. Andreasen Roy J. and Lucille A. Carver College of Medicine, The University of Iowa, Iowa City, IA, USA
The past: early concepts of psychosis, 3 The past: further delineation of psychoses and early definitions of schizophrenia, 4 The present: Schneiderian symptoms, psychosis, and the dominance of diagnostic criteria, 6 The future: beyond diagnostic criteria and the search for fundamental mechanisms, 7 References, 8
Schizophrenia, 3rd edition. Edited by Daniel R. Weinberger and Paul J Harrison 2011 Blackwell Publishing Ltd. Schizophrenia is one of the most important public health problems in the world. A survey by the World Health Organization ranks schizophrenia among the top ten illnesses that contribute to the global burden of disease (Murray, 1996). Because of its early age of onset and its subsequent tendency to persist chronically, often at significant levels of severity, it produces great suffering for patients and also for their family members. It is also a relatively common illness. Although estimates of rates in the general population vary, it appears to affect from 0.5% to 1% of people worldwide. Furthermore, it is an illness that affects the essence of a person's identity—the brain and the most complex functions that the brain mediates. It affects the ability to think clearly, to experience and express emotions, to read social situations and to have normal interpersonal relationships, and to interpret past experiences and plan for the future. Some of its symptoms, such as delusions and hallucinations, produce great subjective psychological pain. Other facets of the illness produce great pain as well, such as the person's recognition that they are literally "losing their mind" or being controlled or tormented by forces beyond personal control. Consequently, it can be fatal—a substantial number of its victims either attempt or complete suicide.
It is also an illness that is conceptually challenging, because its manifestations are so diverse. Over the past several centuries various attempts have been made to formulate a consensus about the definition and essence of schizophrenia. This introduction will review this conceptual history in order to provide a foundation for the later chapters in this book. Even at present, creating a consensus about how best to define the phenotype(s) of schizophrenia is a task that has not yet been successfully achieved. And yet the definition of the concept and its phenotype must provide a foundation for both the study of disease mechanisms and for the development of improved approaches to treatment and prevention.
The past: early concepts of psychosis
The term "schizophrenia" was only coined in the last century, and therefore it is sometimes assumed that it is a "new disease", perhaps a consequence of the development of a complex highly-industrialized world and resultant stresses in lifestyle. Although the name for this illness is relatively new, the concept of psychosis is very old. Based on portrayals of similar psychotic states in early history and literature and on early medical descriptions, we know that schizophrenia-like psychoses have been recognized since at least the first millenium BC.
One of the earliest descriptions of a psychotic condition occurs in the book of Samuel in the Old Testament. After David successfully defends the Israelites against the Philistines by killing Goliath and then wins several subsequent battles, King Saul becomes increasingly paranoid about David's military prowess, to the point of repeatedly making plans to murder David, and even attempting to do it himself:
... the evil spirit from God came upon Saul, and he prophesied in the midst of the house: and David played [music] with his hand, as at other times; and there was a javelin in Saul's hand. And Saul cast the javelin; for he said, I will smite David even to the wall with it. And David avoided out of his presence twice. And Saul was afraid of David, because the Lord was with him, and was departed from Saul. (1 Samuel 10–12)
In fact, Saul eventually begins to have hallucinatory-like experiences, seeking help from the witch of Endor, and also having visions of his former advisor, the deceased prophet Samuel.
If we move on to the classical era in Greece and Rome, there are many descriptions of paranoid schizophrenia-like psychotic states. Greek tragedy is filled with portrayals of individuals who are tormented by psychosis, and are often driven to committing horrendous acts while insane. In The Bacchae, Agave murders her son Pentheus with her own hands, driven by the delusional belief that he is a lion. In Medea, after Jason abandons his wife Medea, she falls into a psychotic rage that drives her to murder their two children with a sword, also murdering King Creon and his daughter by giving them a poisoned robe and chaplet that consumes them in a fiery painful death. In The Oresteia, Orestes is pursued by the Furies until he finally loses his reason and lapses into madness. And there are many more examples.
In the 16th and 17th centuries Elizabethan and Jacobean drama are similarly filled with portrayals of individuals who experience schizophrenia-like psychotic states. Some of the best known are in the plays of Shakespeare. Hamlet, Lear, Othello, and Lady Macbeth all experience psychosis. King Lear is a vivid and powerful example. Three main characters are all "mad": Lear himself, Gloucester, and Edgar (pretending to be a "bedlam beggar"—an escapee from the Bethleham Hospital for the insane in London). As Gloucester says of Lear:
Thou say'st the King grows mad; I'll tell thee, friend, I am almost mad myself. I had a son, Now outlaw'd from my blood; he sought my life.... The grief hath craz'd my wits (King Lear III.iv.169–174)
In addition to these historical and literary portrayals, which document that schizophrenia-like illnesses have been present for at least three millennia, the "medical" literature of these early times provides parallel evidence that psychotic disorders similar to schizophrenia were recognized as important medical illnesses. They are described in the writings of our early medical forefathers, such as Hippocrates, Galen, or Soranus of Ephesus. The disorders described by these forefathers do not map perfectly on to modern classification systems, but they have surprising similarities. Mental illnesses were clearly seen as "physical" in origin, deriving either from an imbalance of humors (yellow bile, black bile, phlegm, and blood) or to an imbalance in the brain. In general, five groups of illnesses were described: melancholia, phrenitis, mania, hysteria, and epilepsy. Mania was essentially equivalent to our concept of psychosis. Psychotic disorders were not, however, further subdivided until the late 19th century.
The past: further delineation of psychoses and early definitions of schizophrenia
Kraepelin (1919) gave us the conceptual framework that created the modern concept of schizophrenia. One of Kraepelin's many great contributions was to take the general concept of psychosis and to subdivide it into two major groups, based on his observation of differences in course and outcome. One group of patients who were psychotic had an episodic course, typically with a full remission of symptoms. A second group of psychotic patients had a chronic course and typically progressed to a deteriorated state. He named these two groups "manic-depression" and "dementia praecox". Although this distinction is so familiar today that we scarcely think about it, it was a major intellectual achievement at the time, and it has influenced psychiatric classification and the concept of schizophrenia for more than a century.
Kraepelin did not, however, consider psychotic symptoms to be the most important features of dementia praecox. When he spoke of symptoms, those that he considered to be most fundamental were what we today would call negative symptoms. Negative symptoms include abnormalities in cognition and emotion: alogia, avolition, anhedonia, affective blunting, and (in some conceptualizations) attentional impairment. Kraepelin said:
There are apparently two principal groups of disorders that characterize the malady. On the one hand we observe a weakening of those emotional activities which permanently form the mainsprings of volition.... Mental activity and instinct for occupation become mute. The result of this highly morbid process is emotional dullness, failure of mental activities, loss of mastery over volition, of endeavor, and ability for independent action. ... The second group of disorders consists in the loss of the inner unity of activities of intellect, emotion, and volition in themselves and among one another.... The near connection between thinking and feeling, between deliberation and emotional activity on the one hand, and practical work on the other is more or less lost. Emotions do not correspond to ideas. The patient laughs and weeps without recognisable cause, without any relation to their circumstances and their experiences, smile as they narrate a tale of their attempted suicide. (Kraepelin, 1919, pp. 74–75)
Such passages in Kraepelin's textbook indicate that he perceived negative symptoms to be the most important symptoms of schizophrenia. Nevertheless, his comprehensive description of schizophrenia covered a broad range of symptoms, including delusions and hallucinations.
Bleuler (1950), on the other hand, tried to clarify the group of schizophrenias by very explicitly attempting to identify what he considered to be the underlying fundamental abnormality. Consequently, he divided the symptoms of schizophrenia into two broad categories: fundamental and accessory symptoms. Bleuler believed that the fundamental symptoms were present in all patients, tended to occur only in schizophrenia, and therefore were pathognomonic. The accessory symptoms, on the other hand, could occur in a variety of different disorders. Depending how one interprets and summarizes his writings, one can argue that Bleuler identified four, five, or six fundamental symptoms of schizophrenia. These included the loss of the continuity of associations, loss of affective responsiveness, loss of attention, loss of volition, ambivalence, and autism. These symptoms correspond relatively closely to those we currently refer to as negative symptoms. They reflect abnormalities in basic cognitive and emotional processes, which (in Bleuler's thinking) provided the basis for other types of symptoms observed in the illness. Accessory symptoms, on the other hand, include phenomena such as delusions and auditory hallucinations. Bleuler wrote:
Certain symptoms of schizophrenia are present in every case and in every period of the illness even though, as with every other disease symptom, they must have attained a certain degree of intensity before they can be recognized with any certainty.... Besides the specific permanent or fundamental symptoms, we can find a host of other, more accessory manifestations such as delusions, hallucinations, or catatonic symptoms.... As far as we know, the fundamental symptoms are characteristic of schizophrenia, while the accessory symptoms may also appear in other types of illness. (Bleuler, 1950, p. 13)
When Kraepelin called the disorder "dementia praecox", he intended to highlight the fact that it had an early ("praecox") onset and therefore differed from another type of dementia described by his friend and colleague, Alois Alzheimer. However, in choosing the term "dementia", he wished to highlight the fact that the illness had a chronic and deteriorating course. His contemporary Swiss colleague, Eugen Bleuler, admired many of Kraepelin's ideas, but he took exception to the fact that chronicity and deterioration were inevitable. Therefore, he chose to rename the illness in order to highlight his own view that a fragmenting of thinking, sometimes referred to as "thought disorder", was the most important feature, and also to eliminate the concept that deterioration was inevitable. He chose the name "schizophrenia" (schiz = fragmenting, splitting; phren = mind, Gk). Bleuler's name eventually prevailed over Kraepelin's. Today many feel that either is an unfortunate choice, because each leads to misunderstanding about the nature of the illness by the general public. Too often people assume that the name refers to a "split personality". However, to date no good substitute has been identified.
Since Bleuler's fundamental symptoms involve cognition and emotion, since negative symptoms (a related but also slightly different concept) also involve cognition and emotion, and since "cognitive dysfunction" in schizophrenia is currently a topic of considerable interest, some clinicians and investigators find the interface between cognition and negative symptoms confusing. The word "cognition" has multiple meanings in cognitive psychology and clinical usage (Andreasen, 1997). Sometimes it refers to all activities of "mind", including emotion and language. Sometimes it refers to "rational" as opposed to "emotional" processes. Sometimes it is used very narrowly to refer to performance on objective neuropsychological tests or experimental cognitive psychology tests. Heuristically, the term "cognition" is probably most useful in the context of schizophrenia when it is used to refer to the broadest meaning (activities of mind). Since negative symptoms are closely tied to defects in basic cognitive processes (e.g., volition, ability to think abstractly, initiation of thoughts and language, attributing affects to experiences), assessing them at the clinical level may provide a relatively direct "window" into cognitive impairments in schizophrenia. While Kraepelin and Bleuler did not refer to their clusters of fundamental symptoms by calling them "negative", this appears to be the point that they were making. In a sense, therefore, negative symptoms may be the most fundamental and clinically important symptoms of schizophrenia.
Neither Kraepelin nor Bleuler actually used the terms "positive symptoms" or "negative symptoms". While various sources for these terms can be cited (Berrios, 1985), one of the earliest and most prominent was Hughlings-Jackson (1931). Although Hughlings-Jackson's work was not published until much later, in the late 19th century Jackson speculated about the mechanisms that might underlie psychotic symptoms:
Disease is said to "cause" the symptoms of insanity. I submit that disease only produces negative mental symptoms, answering to the dissolution, and that all elaborate positive mental symptoms (illusions, hallucinations, delusions, and extravagant conduct) are the outcome of activity of nervous elements untouched by any pathological process; that they arise during activity on the lower level of evolution remaining. (Hughlings-Jackson, 1931)
Thus Hughlings-Jackson believed that some symptoms represented a relatively pure loss of function (negative symptoms answer to the dissolution), while positive symptoms such as delusions and hallucinations represented an exaggeration of normal function and might represent release phenomena. Hughlings-Jackson presented these ideas at a time when Darwinian evolutionary theories were achieving ascendance, and his concepts concerning the mechanisms that produced the various symptoms were clearly shaped by a Darwinian view that the brain is organized in hierarchical evolutionary layers. Positive symptoms represent aberrations in a primitive (perhaps limbic) substrate that is for some reason no longer monitored by higher cortical functions. Thus Huglings-Jackson's concept of negative and positive symptoms rather closely resembles those which are currently discussed. Although most investigators do not necessarily embrace the specific mechanism that he proposed, they accept his view that they must be understood in terms of brain mechanisms, as well as his basic descriptive psychopathology.
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