Cognition is a complex and multidimensional set of mental processes that empower an individual to know the world and the immediate environs and interact accordingly
.Cognition from a broader perspective denotes a relatively high level of processing of specific information which encompasses thinking, memory, motivation, perception, language and skilled movements. The origin of the word cognition is from the Latin word cognoscere meaning to know
The study of cognition (cognitive psychology) has become a crucial discipline in the study of a number of psychiatric disorders, ranging from severe psychotic illness like schizophrenia to relatively benign
The main focus of cognitive psychology is the way humans process information, looking at how information that comes in to the person is treated( called stimuli by behaviourists), and how such treatments leads to responses. It can also be stated as the domain is has interest in variables that transcend between stimuli-input and response-output. The study of internal processes like perception, attention, language, memory and thinking is mainly done by cognitive psychologists.
The history of cognitive psychology can be dated as far back as the end of the 1800s and early 1900s in the works of Wundt, Cattel and William James and its intellectual inception in Aristotles published De Memoria. The study then declined in the mid of the 20
century with the rise of behaviourism after which came cognitive revolution when researchers begun the delve back into the study of the mind based on theories of understanding and processing of information.
Cognitive deficits also known as cognitive impairment or brain fog is an inclusive term used to describe the loss of thinking skills or intellectual abilities such as perception, understanding, acquiring and responding to information
. This affects the way and manner a person reasons out, remembers and thinks. An example of how this peril manifests is trouble in recalling words in a speech and difficulty in solving simple math problems previously solved.
In many psychiatric disorders, cognitive deficits have been an area of research with the prototype work as schizophrenia
. Some psychiatric disorders in which these impairments manifest are:
- Bipolar disorder
- Obsessive compulsive disorder (OCD)
- Somatoform disorder
- Borderline personality disorder (BPD)
- Substance abuse
In the above stated disorders cognitive deficits may result in the inability to:
- Pay attention
- Process information rapidly
- Remember and recall information
- Respond to information quickly
- Think critically, plan, organize and solve problems
- Initiate speech
In addressing the relationship between cognitive deficits and these disorders the following questions I think should be analysed and thought of in line with them:
- What specific link exists between the psychiatric disorders and cognitive impairment?
- What is the underlying psychopathology or neuroanatomy of these impairments and psychiatric disorders?
- How long do these cognitive impairments last in a disorder?
- Is there any impact these impairments have on medical medications on psychiatric disorders? This oration is emphasized on studying cognitive processing in psychiatric disorders, particularly schizophrenia with a spotlight thrown on recent concepts.
Schizophrenia is classified as a multidimensional disease with symptoms and impairments that go beyond psychosis (lunacy). A core feature of schizophrenia is cognitive dysfunction and it is observable at the onset of the disease and persists through the course of the disease.
. Cognitive functioning ranges from moderately to severely impaired patients with schizophrenia. The profile of impairment in schizophrenia involves many of the most essential phases of cognition in humans: memory, attention, reasoning, and speed processing. The extensiveness of this impairment has headed some to conclude that it is a disease with a global profile of neuropsychological impairment.
History of Schizophrenia
The concepts of hebephrenia and catatonia with paranoia into a single disorder dementia praecox was united by Emil Kraepelin in 1896. Kraepelin believed that this was a progressive disorder beginning in young age and early adult life, and showed symptoms of delusions and hallucinations, disorderly thought, loss of concern in the outside world and loss of emotional reactions.
In contrast, a Swiss psychiatrist, Eugen Bleuler proposed in 1911 that there was not a single illness dementia praecox but rather a group of schizophrenias meaning split mind and he classified the symptoms as primary and secondary for this disorder. The primary symptoms he suggested were ambivalence, autism, (loss of interest in the outside world), affective blunting (loss of emotional responses) and altered associations (thought fragmentation). In dissimilarity he felt the secondary symptoms, delusions and hallucinations while often present were not specific to schizophrenia.
The most substantial succeeding attempt to clarify the clinical meaning of schizophrenia was proposed by Kurt Schneider in 1950 and he considered certain symptoms as particularly indicative of the disorder with examples as particular types of hearing hallucinations and characterised these first rank symptoms. This concept of schizophrenia has remained leading into early 21st century diagnostic thinking though it is not without its weaknesses. Today, the world sides with Bleulers affirmation that the disorder does not all the time lead to progressively poorer functioning, but Kraeplins definition of symptoms and causes is still leaned on.
COGNITIVE DEFICITS IN SCHIZOPHRENIA AND ITS CLINICAL RELEVANCE.
What is schizophrenia?
Schizophrenia is a disorder that affects the brain and reflects negatively in the way a person acts, thinks, and sees the world. Individuals with schizophrenia have an altered perception of reality. They often see things or hear voices that dont exist, speak in bizarre or confusing ways, and believe that others are trying to hurt them, or feel like constantly they are being watched by others close to them. With such an unclear line between the real and the imaginary, schizophrenia makes it challengingeven frighteningto negotiate the happenings of everyday life. Persons with schizophrenia may retract from the outside world or act out in confusion and panic.
A greater percentage of schizophrenia cases appear in the late teens or early adulthood. However, schizophrenia can appear firstly in middle age or even at an older age. Seldom, schizophrenia can even affect young children and teenagers, though the signs are slightly different. Generally, the earlier schizophrenia develops, the more severe it manifests itself and its severity. Schizophrenia also appear to be more severe in men as compared to women.
Signs and Symptoms of Schizophrenia
The symptoms of schizophrenia can be classified into 5 categories: delusions, hallucinations, confused speech, disorganized behaviour, and the so-called negative symptoms. However, the signs and symptoms of schizophrenia vary intensely from person to person, both in pattern and severity. Not every person with schizophrenia will all symptoms show up, and the symptoms of schizophrenia may also change over time.
Causes of schizophrenia
The ground causes of schizophrenia are not entirely well-known but, it appears that schizophrenia usually results from a multiple communication between genetic and environmental factors.
Genetic causes of schizophrenia
A strong component of schizophrenia is its hereditary aspect. There is a 10 percent chance of individuals developing schizophrenia if they have first-degree relatives (parents or relatives) having the disorder, as opposed to the 1 percent chance of the general population. Schizophrenia is not determined by genetics but only influenced by it, in instances where schizophrenia runs in family lines, about 60% of schizophrenics have their family members with the disorder. Moreover, individuals who are genetically predisposed to schizophrenia do not always develop the disease, and this is an evidence that biology is not destiny
(Image Source: Debby Tsuang, M.D., M.Sc., University of Washington/VAPSHCS, Special thanks to Dr. Kristin Cadenhead, UCSD)
Environmental causes of schizophrenia
Studies on twins and adoption suggest that a persons vulnerability to schizophrenia is as a result of inherited genes and then environmental factors act on this vulnerability to trigger the disorder. As for the environmental factors involved, more and more study is directing to stress, either in the course of pregnancy or at a later stage of growth. Increased stress is believed to initiate schizophrenia by increasing the bodys production of the hormone cortisol. Several stress-inducing environmental factors that may be intricate in schizophrenia, comprises:
Prenatal exposure to a viral infection
Low oxygen levels during birth (from prolonged labour or premature birth)
Exposure to a virus during infancy
Early parental loss or separation
Physical or sexual abuse in childhood
Abnormal brain structure
Abnormalities in brain structure may also play a role in schizophrenia in addition to the abnormal brain chemistry. Observed in some schizophrenics is enlarged brain ventricles, indicating a deficit in the bulk of brain tissue. There is also evidence of abnormally low function of the frontal lobe, the area of the brain responsible for planning, reasoning, and decision-making. Some studies also suggest that abnormalities in the temporal lobes, hippocampus, and amygdala are connected to schizophrenias positive symptoms. But despite the evidence of brain abnormalities, it is highly improbable that schizophrenia is the consequence of any of problems in any one region of the brain
Effects of schizophrenia
The effects can be devastating both to the individual with the disorder and those around him or her, when the signs and symptoms of schizophrenia are ignored or improperly treated. Some of the possible effects of schizophrenia are:
Interference to normal daily happenings.
Schizophrenia causes substantial disruptions to day-to-day functioning, both because of social difficulties and because everyday tasks become difficult, if not impossible to do. Doing normal things like bathing, eating, or running errands are typically prevented in schizophrenics due to their disorganised thoughts, hallucinations and delusions
People with schizophrenia often withdraw and isolate themselves g causing relationships to suffer. Paranoia also causes persons with schizophrenia to be suspicious of friends and family.
Alcohol and drug abuse.
In an attempt to self-medicate or relieve symptoms, people with schizophrenia frequently develop problems with alcohol or drugs. Also, they may also be heavy smokers, a thwarting condition as cigarette smoke can hamper with the effectiveness of medications prescribed for the disorder.
Increased suicide risk.
Any suicidal talk, threats, or gestures should be taken very seriously since people with schizophrenia have an increased risk of committing suicide. People with schizophrenia are especially likely to commit suicide during psychotic episodes, during periods of depression, and within the first six months after they have commenced treatment.
Treatments for Cognitive Impairment in Schizophrenia
Currently, no pharmacologic or behavioural treatments exists that have received supervisory approval. There are researches that hold promise for the eventual development of a treatment for cognition in schizophrenia.
Various studies using orthodox antipsychotics in schizophrenic patients have shown that their therapeutic efficiency is limited to the positive symptoms of the disease. On the other hand, with the development of different antipsychotics and the acknowledgement that the severity of negative symptoms and cognitive deficits are related to increased functional inability (Green 1996), there has been an effort toward investigating the effects of antipsychotic treatment on cognitive deficits. A meta-analysis of 15 studies recently performed by Keefe et al. (1999) looked at the effects of a variety of different antipsychotic agents like clozapine, risperidone and ziprasidone on cognitive deficits in schizophrenic patients. This meta-analysis results showed that there is enhanced cognitive functions in patients with schizophrenia when different antipsychotics are compared with conventional antipsychotics. Cognitive functions like verbal fluency, digit-symbol substitution, fine motor functions, and executive function responded best to treatment with different antipsychotics. Processes to enhance attention were also positive; but learning and memory functions were not as responsive. It is likely that some of the detected improvement is due to the reduced extrapyramidal side effects of different antipsychotics. This is because the tests that showed the greatest improvement upon treatment with different neuroleptics all involve psychomotor speed as well as cognition (Keefe et al. 1999).
Although all currently available antipsychotic agents have some antagonistic activity at D2-receptor sites, they vary substantially with regard to their activity at other receptor sites. Atypical antipsychotics affect multiple neurotransmitter systems, including cholinergic, adrenergic, serotonergic, and dopaminergic types. It is the activity of these agents at non-D2 receptor sites that may have important clinical consequences, including selective effects on the cognitive deficits of schizophrenia. Unfortunately, at present, the relationship between receptor subtype and cognitive function is poorly understood (Meltzer and McGurk 1999). Despite the fact that the results of the meta-analysis by Keefe et al. (1999) appear promising, the results of large-scale clinical trials are required to elucidate the extent to which specific cognitive deficits in schizophrenia can be improved by currently available treatments and what neurotransmitter receptors are involved.
Although schizophrenia is a chronic disorder, there is help available. With support, medication, and therapy, many people with schizophrenia are able to function independently and live satisfying lives. However, the outlook is best when schizophrenia is diagnosed and treated right away. If you spot the signs and symptoms of schizophrenia and seek help without delay, you or your loved one can take advantage of the many treatments available and improve the chances of recovery.
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