SCHIZOPHRENIA IS COGNITION IMPAIRED IN SCHIZOPHRENIA?

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1 CHAPTER 10: DISTURBED COGNITION IN SCHIZOPHRENIA Traditionally, functioning of the mind is described under four headings: perception, emotion, cognition, and conation. Perception refers to awareness of surroundings, usually through sensory functions such as seeing, hearing, smelling, tasting or touching. Emotions refer to feelings such as happiness, sadness, anger etc. Conation refers to behaviour or actions, e.g., walking, cooking etc. Cognition is derived from the Latin word Cognitio, which means to know. In modern psychology and psychiatry, the phrase cognitive functions is used to describe various aspects of thinking such as attention, concentration, comprehension, memory, orientation, abstraction and judgement. Cognitive functions range from simple abilities such as counting change from a dollar, to complex tasks requiring concentration and coordination such as playing chess, driving a car or writing poetry. IS COGNITION IMPAIRED IN SCHIZOPHRENIA? The simple answer is yes. However, there are some controversies and caveats about it. The controversies become evident from a historical review of the concept of schizophrenia. At first, pioneering psychiatrists such as Kreapelin and Bleuler believed that schizophrenia, over a period of time, causes a cognitive decline. In the intervening years, others viewed schizophrenia from a narrower perspective, and described it in terms of distorted thoughts (delusions) and perceptual problems (hallucinations) without the involvement of cognitive functions. These views have again changed over the past two decades, and we have now come to believe that cognitive impairment is commonly associated with schizophrenia. Schizophrenia is now considered to have three or more sets of symptoms. These are commonly known as positive symptoms, negative symptoms, disorganization symptoms and cognitive deficits. The relationship between cognitive disturbances and other symptoms of schizophrenia is not clearly understood at present. It has been observed that some people experience cognitive problems much before they develop positive symptoms, while 136

2 others acquire cognitive deterioration after the first episode and with subsequent relapses. The emergence of cognitive symptoms, generally speaking, augurs an unfavourable outcome in the long term. There are two caveats though, to remember. First, there is a great variability in the occurrence of these different sets of symptoms. Some people experience positive symptoms only, while others may have more negative symptoms, and a smaller proportion of affected individuals develop cognitive difficulties. Second, the extent of cognitive involvement may also vary between different individuals. The majority of people diagnosed with schizophrenia experience only subtle difficulties, while a smaller group (about 1 in 5) seem to show more striking cognitive deficits. HOW DO COGNITIVE PROBLEMS AFFECT DAILY ROUTINE IN SCHIZOPHRENIA? The person experiencing cognitive difficulties often complains of speededup thinking, racing thoughts, feeling mixed up, and having poor concentration or being forgetful (memory problems). When these problems are mild, the person will have difficulties with reading, writing or watching TV. People with a greater degree of cognitive problems will be unable to carry out tasks (e.g., cooking, shopping, etc.), manage their money, and look after themselves. This may result in poor hygiene, malnutrition, and self-neglect. The worst type of cognitive impairment results in potentially dangerous behaviours such as walking into traffic, leaving the stove on, or mixing up medications. Over a longer period of time, cognitive difficulties lead to consequences such as unemployment, disability, poverty, debts, and excess dependency. Two of the common and frustrating problems is forgetting to take medications, and forgetting to keep medical appointments. WHAT CAUSES COGNITIVE DEFICITS IN SCHIZOPHRENIA? It is now generally believed that schizophrenia is a brain disorder, and the variety of symptoms experienced is the result of an impaired function in different parts of the brain. The part of the brain located in the forehead (the frontal lobes) holds the key to many cognitive functions. Recent research 137

3 indicates that other structures located deep inside the brain may also be involved. Damaged nerve cells (neurons) located in these parts interfere with the transmission of information from one part of the brain to the other (neuronal circuits), produce a chemical imbalance, and lead to cognitive decline. Some of the speculated mechanisms include an inability to distinguish between useful and useless information (filtering), resulting in an information overload; failure to have a working memory to juggle with available information such as performing mental arithmetic; difficulty in shifting the focus from one topic to another, and defects in social cognition (e.g., reading people s reactions in social settings). HOW TO GET COGNITIVE PROBLEMS ASSESSED? There are three possible methods of identifying, assessing, and monitoring cognitive problems. These include periodical reviews by a psychiatrist, specialized testing by a psychologist, and diagnostic brain scans. Of these, regular monitoring in a clinical setting is often the only feasible option. Psychological testing to assess the cognitive problems in schizophrenia is a sophisticated procedure, and is not readily available everywhere. There are few psychologists who have the required training and expertise to perform such tests. Brain scanning techniques such as MRI hold the promise of precisely identifying and monitoring cognitive problems. But these techniques are still being developed, and are not easily accessible in all places. WHAT CAN BE DONE ABOUT IMPAIRED COGNITIVE FUNCTIONS IN SCHIZOPHRENIA? There are two ways of dealing with cognitive problems: treatment and prevention. Treatment strategies include the use of appropriate medications, maintaining an active daily routine, and participating in cognitive remedial therapy programs. Antipsychotic medications have been known to improve cognitive problems dramatically, especially during the early part of treatment. The newer antipsychotic medications (risperidone, olanzapine, quetiapine, ziprasidone and clozapine) seem to have an edge over the older generation of medications in producing a greater degree of improvement in negative symptoms and cognitive 138

4 symptoms. It is also important to remember that using inappropriately higher doses of medication may actually worsen, instead of improving, certain aspects of cognition. Distinguishing frequently associated symptoms such as anxiety, depression or obsessions, and treating them with appropriate medications such as antidepressants, also makes a big difference in improving cognitive functioning. Cognitive remedial therapy is a relatively new approach that is not widely available for routine use. This involves practicing various mental exercises, usually with the help of a computer. Other simple steps include the use of various memory aids (e.g., using a dosing box to take medications regularly, and a calendar to note down appointments), and generally maintaining an active structured routine. Like many other things in life, the principle with cognition is use it or lose it. In the small proportion of individuals who are prone to develop a progressive type of cognitive deterioration, prevention is more critical. Initiation of antipsychotic medications early, soon after the first symptoms of illness appear, may have some value in limiting the deterioration in later years. Strict adherence to the recommended dose of medication over a period of time (possibly 2-5 years) is also essential in lessening the degree of deterioration. Keeping the symptoms under control and avoiding relapses of illness is perhaps the best known approach to prevent cognitive deterioration. It is important to note that the indiscriminate use of recreational (street) drugs can worsen cognitive functions in vulnerable individuals. CURRENT LIMITATIONS While a lot has been learned from research over the past two decades, several questions still remain unanswered. First of all, it is not known if there are certain cognitive disturbances that are unique to schizophrenia. Cognitive problems of different sorts are seen in a number of other disorders such as Alzheimer s disease, and the type of difficulties that are 139

5 specific to schizophrenia are yet to be clearly identified. Second, there is a continuing debate about the progression of cognitive problems: whether they get worse over a period of time or not? Third, there is a need to develop a method of identifying individuals that are more prone to develop cognitive problems than others. Having such a predictive strategy will help early recognition and possible prevention. Fourth, the areas of the brain that are involved in producing cognitive problems need to be pin-pointed. Lastly, there is a need to develop new treatment strategies. Cognitive deterioration is one aspect of schizophrenia for which we do not have an effective treatment strategy at present. Clozapine is, so far, the most effective treatment available to deal with the cognitive problems; but it demands extra monitoring efforts from the clinic staff, clients, and the families. RESEARCH IN PROGRESS Cognitive aspects of schizophrenia have become the most active area of research in the past five years. Researchers have been vigorously working on identifying the exact nature of cognitive problems experienced by people with schizophrenia, and are attempting to develop appropriate tests to measure and monitor them. Functional imaging has been another active area of research. Scanning devices such as the MRI and PET imaging are being used to study the brain mechanisms involved in causing cognitive problems. Also, major pharmaceutical companies are actively investing in the development and testing of newer medications that are likely to offer greater benefits in improving cognitive problems. Psychologists, occupational therapists, and specialists in education are involved in developing various cognitive remedial strategies that could be incorporated into day treatment programs and daily routine. CONCLUSION Dealing with the symptoms of schizophrenia has been similar to peeling the layers of an onion. At first it appeared that positive symptoms were the only problem. Antipsychotic medications have been greatly helpful in controlling these symptoms. As these medications became widely available, the problem of negative symptoms became apparent. The new second generation antipsychotic drugs offer some hope that negative symptoms 140

6 can also be conquered. Cognitive problems are the next ones to tackle in the ongoing battle with this monstrous disorder. Cognition is a tough nut to crack. Understanding its origins and mechanisms in the brain is likely to help us not only in dealing with schizophrenia, but also in unravelling the mysteries surrounding other mental illnesses too. 141