Schizophrenia is a disorder which affects approximately 1% of the world population, has a 10% suicide rate, an estimated $20 billion in lost productivity and $11.1 billion in medical costs in the United States in 1980 (Andreasen, 1995). The primary characteristics are disturbed language, communication, thought and perception (Davidson, 1993 p. 1). There are two distinct types of symptoms, the positive (abnormal activity, such as delusions and hallucinations) and the negative (lack of activity, such as avolition, affective blunting) (Andreasen, 1995). Davidson (1993, p. 2) also identifies three phases of the disease process, each of which presents its own unique problems. Onset begins with social skill deterioration, and difficulty completing everyday tasks. The acute phase encompasses such items as delusions, hallucinations, and distorted thinking. Finally, the remission phase is marked by the passing of the distortions, with a return to more normal functioning, although oftentimes not as effectively as before the onset. Depending upon the phase and severity of the disease, a patient may have severely different psychological fields as well (Anscombe, 1987). However, Green (1996) points out that in a literature review, it has been shown that the degree of psychosis does not act as an indicator of the subsequent recovery.
Schizophrenia can be expressed in a patient through positive and/or negative symptoms. Both positive and negative symptoms generally result in learning difficulties, though through different mechanisms. This specifically includes (for positive symptoms), derailment, tangentiality, incoherence, illogicality, circumstantiality, pressure, distractible speech and clanging (Andreasen, Arndt, Alliger, Miller, & Flaum, 1995). For negative symptoms, the effects include psychomotor poverty, amotivation, apathy, loss of self-esteem, and reduced concern for reward and reinforcements (Hogarty and Flesher, 1992).
The results of both spectrums are exhibited in learning deficits in different areas, including: decreased attention, poor abstract thinking, poor planning and problem solving, poor memory, decreased verbal skills, poor organizational skills (Davidson, 1993, pp. 4-5), selection between relevant and irrelevant stimuli, poor flexible shifting of attention, poor comparison of earlier stimuli to current stimuli, altered evaluative higher processes (Brenner, 1986, pp. 138-139), impoverished cognitive schema, visual impairments, and chunking impairments (Hogarty and Flesher, 1992).
Schizophrenia can also be defined as an inability to sustain an intentional focus to attention. This inability can lead to a lack of control over the mental processes. The patient is at times passive within their own mind. Additionally, according to Hogarty and Flesher (1992), it appears that the patient has an inability to “self-edit”, resulting in both verbal and internal established but inappropriate responses. A result of this inability to direct a train of thought, access to long-term memory is compromised (Anscombe, 1987).
(Brenner, Hodel, Roder, & Corrigan, 1992) provide the following pictorial description (Figure 1), which shows the “vicious circles” that serve to decrease cognitive functioning and the ability to learn
Schizophrenic patients have been studied extensively for cognitive functioning. Although not all schizophrenic patients exhibit cognitive deficits (Back et al., 1996), there is ample data to show that these defects do occur with regularity.
General testing of Schizophrenics shows that in specific tests, such as the Hiscock Forced-Choice Method, schizophrenics with cognitive impairments scored with 84.72% accuracy, compared to 97.44% accuracy for those with no cognitive impairment. Additionally, the time on Rey Dot Counting differed significantly. Cognitively impaired schizophrenics took over 4.6 seconds, while those without impairment were under 3 seconds (Back et al., 1996).
Extrapyramidal symptoms (EPS) are a result of long-term antipsychotic use in schizophrenic patients. Aside from the cognitive deficits attributable to the actual disease process, it appears that the EPS itself involves the presentation of additional difficulties in learning. While some noncognitive aspects of EPS such as bradykinesia can alter the results when testing for neuropsychological deficits, statistical analysis shows that neuropsychological deficits as a result of increasing severity of EPS in the area of learning are not related to the physical manifestations (Palmer, Heaton, & Jeste, 1999).
The decreased ability on these tasks is the result of deficits in two general areas, memory and attention. These are inextricably linked within the context of learning.
Attention can be divided into two subcategories: preattentive (automatic), and selective (effortful) (Anscombe, 1987). It has been suggested that the preattentive processes are impaired, with alternative stimuli in the environment not being filtered properly. However, it is the selective attention that has been found to be more affected. It appears that schizophrenics have difficulty with the first stages of processing new material, focusing on the stimuli with selective attention (Anscombe, 1987). This can be seen in the act of the patient’s attention being captured by an irrelevant word or thought. It is as if the selective attention required to process the stimuli has been sublimated. This loss of selective attention allows the initial, preattentive forms of attention to proceed with no controls. Patients describe it as follows: