Abstract
Schizophrenia is a mental condition that affects about 1% of the world’s population. It's often associated with attempted suicides with 50% of those affected by the condition attempting suicide at some point of which 9-13% are fatal . The symptoms of schizophrenia are grouped into three: positive symptoms, negative symptoms and cognitive deficits. Cognitive symptoms have been known to be an indicator of both the disease outcome (prognosis) and the response to the treatment. They include the inability to pay attention, language difficulties, memory dysfunction, poor interpretation of social cues and cognitive inflexibility. Patients with schizophrenia have difficulties in assimilating new memories in addition to retrieving information that was stored in the past. Patients with schizophrenia have difficulties in assimilating new memories in addition to retrieving information stored in the past. Schizophrenics have been shown to lack several key skills which are necessary for social cognition. For instance, schizophrenics lack mental inference which refers to the ability to deduce the mental states of those they interact with. The loss of sensation in body parts is attributed to the psychological processes in relation to the ego of schizophrenic. The ego of a schizophrenic is often fragile and gradually descends into narcissistic tendencies with the progression of the disease. Several studies have shown that schizophrenics have a poor sense of perceptual organization. Through the use of psychophysical tasks, it has been noted that the deficits in visual organization can lead to superior performance particularly when the stimulus are to be identified independently away from their contexts. The patients often perform poorly in semantic games such as semantic fluency, recall of single words, categorization and memory. This can be attributed to the disrupted ability of the brain of schizophrenics when it comes to the retrieval of input signals in addition to the poor ability to assimilate new concepts. This paper will evaluate how schizophrenia affects different aspects of the cognitive process as well as the research that has been carried out on cognitive processes in relation to schizophrenia.
1.0 Introduction
Schizophrenia is lifetime mental condition that affects about 1% of the world’s population. The condition often leads to either attempted suicides with 50% of those affected by the condition attempting suicide at some point of which 9-13% are fatal. The symptoms that are associated with schizophrenia are categorized into three: positive symptoms, negative symptoms and cognitive deficits. Positive symptoms are so called because they result in “extra” behavior and functioning. These symptoms include: delusions and hallucinations. The hallucinations become a threat to the patient given that they are often paranoid in nature hence the patient is out of touch with reality.
Negative symptoms are so named because they cause a “deficiency” of normal behavior and functionality. They include: blunt emotions, avolition (lack of initiative), anhedonia (lack of pleasurable feelings) and social withdrawal. Social withdrawal is a symptom that is often associated with depression. Negative symptoms are only partly eliminated by antipsychotic treatment as the antipsychotic drugs have been shown to result in further manifestation of the symptoms because the drugs trigger blockage of dopamine receptors which are known to attenuate the feeling of self worth.
Cognitive symptoms have been known to be a predictor of both the disease outcome and the response to the treatment. They include the inability to pay attention, language difficulties, memory dysfunction, poor interpretation of social cues and cognitive inflexibility. These deficits are known to necessarily be treated by anti-psychotic drugs hence research in the past decade has been focused on the alleviation of these symptoms.
2.0 Aspects of cognitive processes and associated theories and research
2.1 long term memory and learning
Patients with schizophrenia have difficulties in assimilating new memories in addition to retrieving information that was stored in the past. To further explain this model, one scholar came up with a concept in which he termed the stored memories as stored contextual information meant to be drawn out in order to assimilate the new concepts. However for schizophrenics, the connection between past and present is severed hence there is impaired memory function.
An improved version of this theory postulates that the memories of past experiences are stored but the access to this information is altered. As a result there is a rapid release of unexpected outcomes from the long term memory. The intrusion of new experiences from the surrounding is poorly perceived resulting in ambiguous sensory input. As a result of the collision between the ambiguous input from new experiences and the unexpected outcomes of the stored experiences, the patient suffers from hallucinations and delusions.
The deficits in memories have been linked to biological and neuropsychological dysfunction. One theory postulates that the defects in memory are as a result of the dysfunctional circuitry between the hippocampus and the sub cortical regions of the brain. According to this theory, the dopamine activity within the circuitry is exaggerated thus resulting in down regulation between the hippocampus, the nucleus cumbens and the mesolimbic system.
As a result of the defects in memory, schizophrenics often have problems with learning new concepts. They may excel in a particular field which they were knowledgeable in prior to the onset of the disease. They are often comfortable with repetitive tasks. It is often difficult for patients with schizophrenia to proceed with their education as the disease progresses since they become less capable of retrieving information.
2.2 PERCEPTION
This refers to the ability to group the objects in the visual context into stimulus elements that are eventually grouped together in order to lead to recognition of the emergent objects although the stimulus remains the same. Several studies have shown that schizophrenics have a poor sense of perceptual organization. Through the use of psychophysical tasks, it has been noted that the deficits in visual organization can lead to superior performance particularly when the stimulus are to be identified independently away from their contexts.
However for schizophrenia it has been found that the perception abilities are dependent on the task parameters. Studies have shown that anomalies in perceptual grouping among schizophrenics are dependent on the degree to which organization ought to be imposed on the stimuli and also the extent to which the stimuli might be grouped. It has therefore been deduced that for schizophrenics have a poor perception of the elements that have less properties for configuration and where the perception of the groups is pegged on past experiences, current context and other factors. On the other hand, the processing of stimuli with pre-determined structure and other stimuli that possess configural properties that are strong (e.g., configural stimuli with and without continuous contours) is untainted in schizophrenia.
There has been considerable evidence that has been gathered which show that the schizophrenics are inclined to have an impaired ability to recognize faces. Studies have implicated the general decline of the memory function as the main cause for the poor ability to identify faces although the decline in cognitive abilities has also been found to be a contributing aspect. It has been postulated that as a result of the decline in the ability of the schizophrenics to assimilate new images and also the blurred output from the memory contribute to the declined ability to recognize the faces. In addition, the poor perceptive abilities as a result of the inability to group the stimulus together contributes to the poor identification of the faces. In addition to poor face identification, schizophrenics have also been reported to have a problem with the judgment of the age of a given individual. They are also prone to be fixated with particular features of the face which is as a result of the declining ability to group stimuli. Experiments involving healthy subjects and schizophrenics show that the schizophrenics tend to be more inclined with irrelevant features of the face when taken through experiments that involve sorting through histoforms and faces. This points to the fact that stimulus driven processing that occurs in sequences for the schizophrenics.
The inability to identify faces has also been attributed to the defects in the memory and the visual cognition of schizophrenics. The defects in visual cognition often make it difficult for the individual to compress the different facial features into a whole face then eventually be able to tell who the person is. The deficits in the memory account for the fact the schizophrenics often have difficulties in assimilating new concepts in addition to being unable retrieve previously stored information about the people they may have encountered before.
2.3 Social cognition
This refers to the ability to perceive process and interpret information that is related to self and others which is necessary in everyday interactions with other people. Schizophrenics have been shown to have an impaired sense of social cognition. Social cognition is one of the key symptoms of schizophrenia which normally begins to manifest right after the psychotic episodes begin to occur. Schizophrenics have been shown to lack several key skills which are necessary for social cognition. For instance, schizophrenics lack mental inference which refers to the ability to deduce the mental states of those they interact with them in addition to being able to accurately deduce their intentions. In addition, they also lack the ability to perceive their emotions, to read and interpret certain social cues and also lack the ability to accurately reason when presented with certain social information. The social cognitive deficits can be attributed to the neuro-cognitive defects. They particularly manifest for schizophrenics who are either in their adolescent years or in their early adult years.
2.4 Language
One of symptoms that marks schizophrenia is the unintelligible words that schizophrenics tend to utter at times. This is regarded as one of the strongest indications of maladaptive social cognition and functionality. It is postulated that the schizophrenics do not necessarily have a problem with the expression of themselves rather the problem lies in the train of thought.
According to one scholar, the language disorders are due to the incoherence of the thought pattern an aspect that can be attributed to the lack neurological coordination in the brain of the schizophrenias. The language disorders can therefore be termed as tautological i.e. We can deduce the extent of the disorder in thought based on the language disorder. However this might not necessarily hold as true for all patients. There are patients who might have severe defects in their thought process but opt to say nothing. There are those who might have their thought process intact but they lack the ability to make use of their language skills to express their thoughts.
It is believed by many scientists that the identification of the brain function of schizophrenics with language disorder can be best understood based on the study of brain function of brain damaged patients. Based on this assumption, there is evidence to suggest that patients with damage to the right hemisphere of the brain are more likely to exhibit the same language dysfunction as seen in schizophrenics. This is particularly seen in patients who have lesions in the right hemisphere of their brain. However the results of such studies have not entirely led to the conclusion that all schizophrenics with language disorder have the disorder as a direct result of poor co-ordination in the right hemisphere of their brain.
Language processing is known to comprise of three levels which are: the lexical level, sentential level and the discourse level. Each of these levels is known to be dependent on other cognitive aspects such as working memory, attention and ability to read. The lexical level comprises of simple words. The sentential level is comprised of syntactic categories into which the words are inserted such as nouns and verbs. The discourse level comprises of higher order structures whereby one begins to conceptualize the causation of the words spoken, the focus on the speaker and the order of events in any setting of speech.
It has been noted in studies that schizophrenics tend to be obsessed with the features of too many words. The patients often perform poorly in semantic games such as semantic fluency, recall of single words, categorization and memory. This can be attributed to the disrupted ability of the brain of schizophrenics when it comes to the retrieval of input signals in addition to the poor ability to assimilate new concepts. Studies have also shown that schizophrenics experience difficulties in recognizing words in sentences. Studies involving both normal and schizophrenics demonstrate that the schizophrenics are unable to identify words put in sentences but if the words are isolated and grouped, the recognition of the words improves.
Normal people are often able to recall a number of words in a list if the words are prearranged in a particular sequence which enables them to encode the words and reproduce them easily. In studies involving both normal subjects and schizophrenics, it was found that schizophrenics are able to recall a long list of words in an unorganized manner. This is a reflection of the poor co-ordination with the temporal lobe of the schizophrenics thus resulting in the disorganized output of information.
However it has also been noted that the ability of the schizophrenics to recall can gradually improve if the list of words is pre-arranged in a particular manner and the patients are given enough time to go through the list.
Based on such studies, it has been concluded that the language defects among the schizophrenics are not at the lexical level but at the retrieval level. Given associative links such as groups of words or words that are accompanied by pictures, the schizophrenics have been known to have an above average to recognize the words and recall them.
2.5 Attention and consciousness
Patients with schizophrenia have been known to have deficits with paying attention and being conscious of their environment. Researchers have come up with several hypotheses as to what causes these deficits.
One of the hypotheses postulates that the schizophrenics have poor attention because the nervous system is constantly inundated by the inability of their nervous system to filter through the sensory inputs resulting in an avalanche of outputs that are disorganized. The disturbances in the temporal processing of information by the brain results in the poor attention span and lapses in consciousness. This hypothesis is further supported by the evidence that the brain structures (e.g. Cerebellum) and neurotransmitter systems such as dopamine do not function normally in the brain of schizophrenics.
The neurons in the brain fail to appropriately coordinate their functions. As a result neural centers located in the brain, (nuclei) fail to encode, process, and transmit information as required. These failures trigger inconsistent interactions between neural centers, which may affect perceptual and motor processes. The spread of such failures may lead to impaired consciousness as seen in schizophrenics.
Given that consciousness allows an individual to monitor willed actions, the impaired consciousness results in the negative behaviors and the incoherent behaviors that characterize schizophrenia. The auditory hallucinations are also as a result of the failure to monitor willed intentions. The absence of a signal triggers the neural system to interpret an action as unwilled. The relevant signal is supposed to help in the comparison with reafferent signal that are normally received as a result of willed actions. It has been hypothesized that such a signal is delivered as a result of a mechanism that is known as corollary discharge. The presence of such a signal normally creates a sense of urgency. However if the signal is absent, it is postulated that a thought might be inserted by the system.
The paranoid delusions and delusions of reference are postulated to be as a result of the deep rooted problems as a result of defects in consciousness and attention. This has been termed as metarepresentation. It has been stipulated that schizophrenics are unable to recognize that one is in a particular mental state in addition to the efference copy model that has been described above. This model therefore presupposes that for an individual to perform a certain action, they need to not only monitor their goals but also their intentions which are heavily reliant on consciousness.
2.6 Sensation
The loss of sensation in body parts is attributed to the psychological processes in relation to the ego of schizophrenic. The ego of a schizophrenic is often fragile and gradually descends into narcissistic tendencies with the progression of the disease. This descent occurs in three stages: fear of object loss, loss of object and transference to the body.
In the first stage, the ego is inclined towards personal objects. In the second stage, the ego may react by taking a personal withdrawal from objects. The ego therefore views the body as the only form of object that it can relate to. During the third stage, the feelings and attitudes that the person had towards objects are now transferred to the body. This includes both the positive and the negative feelings. The individual now begins to view their body as the foothold for the survival of their ego. Therefore they express fear of the loss of their body parts often and even claim that a particular part of their body is lost.
Given the unstable nature of perception of their surrounding, schizophrenics may end up harming their bodies without feeling or perceiving the danger that they are in. Further deterioration of the ego leads the patient to begin to mutilate parts of their body which they often seem to be unconscious while doing. This corresponds to the ego of the individual which at this point feels that they need a new body image. The acts of mutilation are often accompanied by pain but the schizophrenic often interprets this feeling as a feeling of accomplishment.
Such sensations are further aggravated as the patient descends further into feelings of low self worth with the progression of the disease. It therefore becomes necessary for the patient to be constantly under watch in order to prevent incidences that may be fatal.
3.0 Conclusion
Based on the evidence from the studies, schizophrenia can be said to have an effect on several aspects of cognition: learning, memory, attention, sensation and language abilities. Schizophrenics therefore face daily challenges that impede their interaction with others and their ability to be self reliant. More studies should be done to find means of improving the quality of life of schizophrenics.
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