Tag: characteristic cognitive processes in schizophrenia

Implications of Memory Pathology in Schizophrenia

I’m going to change it up with a short paper I wrote in my cognitive psychology class on schizophrenia.  I chose this paper because it discusses theoretical implications for any explanation of the cognitive aspects to schizophrenia via an analysis of three case studies involving deficits and/or surpluses in patients with schizophrenia.  Unfortunately, as the class was a couple of years ago I don’t presently have the book that contained the case studies I was basing the paper on, so I can’t provide references to the case studies other than by the patients name (a characteristic practice in the field).  So if anyone knows the exact case study name(s) and/or the scientists that were credited for them, let me know.


Schizophrenia is frequently complicated by a decline in general intelligence.  Underlying the decline in intellectual capacity are several neuropsychological deficits that are thought to contribute. Deficits in memory and executive functioning are frequently witnessed in these cases, but their relationship to the general decline is not so clear.  The implications of the three case studies to be assessed in this article conjointly challenge the contemporary idea that specific neuropsychological defects in memory and executive function are part of the larger pattern of general intellectual deterioration in patients with schizophrenia.

The patient TC represents the typical schizophrenia of impaired memory and impaired frontal lobe functionality as each part of the larger pattern of general intellectual decline.  His poor performance on virtually all long term memory tests justifies the claim that his long term memory is extremely impaired.  Also consistent with the conventional theory is manifestly impaired frontal lobe functionality; in the Wisconsin Card Sorting Task he displayed an inability to switch rules even when asked.  Language functionality in TC is a bit of a different story: he has trouble understanding semantics but can understand grammar.  Given his rather significant decline in general IQ (from 113 to 68) perhaps it is the case that semantic memory is more central to the pattern of intellectual decline but memory for grammar is somewhat of an independent module.  This may become even more clear when we compare TC with another case study of the patient DS.

There are striking similarities because DS and TC, however there are also significant differences.  Both DS and TC exhibited motivation with respect to the cognitive testing; this suggests that in some ways the extent and pattern of their cognitive disabilities spared them important social skills like motivation and the ability to cooperate.  This is somewhat of an anomaly; in most schizophrenics there is a marked decline in cooperation and motivation.  Perhaps in most other cases where patients are uncooperative and unmotivated, we can infer that schizophrenia is only indirectly linked with these social deficits insofar as, perhaps, it caused the social ridicule in various environments because proper action was taken, et cetera.  Thus, cognitive deficits of schizophrenia may be functionally distinct from the individual’s level of cooperation and motivation.  Like TC, DS exhibits a significant deficit in long-term memory, with a spared short-term memory.  However, the manifestation of DS’s compromised long-term memory is comparatively complex; procedural memory is spared, while semantic, autobiographical and recognition are all in the severely impaired range.  Also different from TC was DS’s comparatively decreased decline in general IQ (115 to 101) and his normal functioning of the frontal lobes and executive processes.  Thus, it seems DS’s neuropsychological deficits are relatively distinct from the general deterioration of intellectual capability.  DS’s relatively stable IQ level may be attributable to his intact executive functioning, or it also may be attributed to his academic background prior to the onset of illness: that he can still understand languages he learned prior to onset suggests he has retained a significant portion of his intellect.  Perhaps too, as we compare TC with DS, we may suggest that the general deterioration of intellect in schizophrenia is at least lessened if the individual had a rather extensive and sophisticated education, as is the case with DS.

EN’s case is a bit uncharacteristic of schizophrenia: that she “appears superficially well and has managed to find part-time work” suggests that, at least with respect to her ability to find work, her illness has not completely devastated motivation.  The delusional aspect of her schizophrenia is manifestly the most important: in an interview she actually lapsed into delusional confabulation, whereby the patient produces new delusions and delusional memories apparently spontaneously.  This is very different from the memory impairment of both DS and TC; in her case it suggests that the general pattern of intellectual impairment is functionally irrelevant to memory; her memory impairment thus seems independent of any other further association.  While DS’s memory impairment is also separate from executive functionality, EN’s manifestation of memory impairment is markedly different: EN’s memory deficits manifest only in her confabulation.  While DS suffers from memory impairment, we may say that EN suffers not from impairment, but from “deranged and corrupted” memory.  Additionally, an inference we can draw is that her memory impairment as manifested in delusional confabulation seems functionally linked with her abnormality in autobiographical memory.  This is interesting because DS also shows some problems in autobiographical memory, but in his case does not seem to be casually linked with the onset of delusional confabulations.

In all three cases we see the presence of memory impairment; however only one case supports the idea that memory impairment is associated with the larger pattern of intellectual decline.  There is also an important qualitative distinction to make: it seems that delusional confabulation is qualitatively different from the long-term memory impairment of DS and TC.  It is not enough to merely say that EN’s memory is not functioning with the same degree of accuracy as the normal subject; we must say that in fact her memory is functioning on a completely different level than the normal subject.  Lastly, we may conclude that it is not at all law-like that the general intellectual impairment and the specific neuropsychological deficits in schizophrenia are directly linked with the positive and negative symptoms of the disorder.