Mental Health Nursing

open access articles on mental health nursing

Cognitive functions


“My whole mental power has disappeared, I have sunk intellectually below the level of a beast” (a patient with schizophrenia, quoted by Reference Kraepelin, 1919, p. 25). 1


The word ‘cognition’ means the use of conscious mental processes and it has its origins in classical terms relating to the concept of knowing.2,3 Cognition is the mental action or process of acquiring knowledge and understanding through thought, experience, and the senses. It encompasses various aspects of high-level intellectual functions and processes such as attention, memory, knowledge, decision-making, planning, reasoning, judgment, perception comprehension, language, and visuospatial functions.4 Cognition in a broad sense means information processing, a relatively high level of processing of specific information including thinking, memory, perception, motivation, skilled movements, language and ‘executive’ functions.5 Conservatively, cognition in humans is defined as “all the processes by which the sensory input is transformed, reduced, elaborated, stored, recovered and used”.6 Human cognition can be conscious and unconscious, concrete or abstract, as well as intuitive (like knowledge of a language) and conceptual. Cognition is involved in every psychological function.7

Cognitive functions

The study of cognitive functions largely remained in the domain of cognitive psychology and neuropsychology. Cognitive psychology originated in the 1960s in a break from behaviourism. The ‘cognitive revolution’ was the result of interdisciplinary activities of the psychology, linguistics, neuroscience, computer science, anthropology and philosophy in the 1950s.8 Ulric Neisser coined the term ‘cognitive psychology’ in 1967.7 Jean Piaget is known for studying the cognitive development in children. Generally the cognitive function is described in terms of the concept of intellectual ability. The three main approaches to the human cognitive functioning development are Jean Piaget's approach, information processing approach and psychometric approach.9 Higher levels of psychological well-being were associated with better global cognitive function and performance in multiple cognitive domains.10 Social cognition may be defined as cognitive process that involves other people. It is the ability to correctly process information and use it to generate appropriate response in situations.11

Cognitive functioning refers to multiple mental abilities, including learning, thinking, reasoning, remembering, problem solving, decision making, and attention, as well as executive functions which exerts control over the utilization of more basic processes.12 Understanding cognitive functioning needs a lifespan approach.12 The basic underlying constructs of abilities such as general intelligence (g), fluid intelligence (Gf), and crystallized intelligence are important to understand cognitive functioning.13  Domains of cognitive functions are sensation and perception, motor skills, attention and concentration, memory and executive functioning.14


Sensation, the first step of the complex process of cognitive process, is defined as the psychological function which transmits a physical stimulus to perception’ through sense organs. The brain transforms sensory messages into conscious perceptions.14 Sensory transduction is the translation of the sensory stimulus into neuronal activity, which involves a variety of physical and chemical mechanisms.15


Perception is the process of adding meaning to raw sensory data. Perception is the organization, identification, and interpretation of sensory information in order to represent and understand the presented information, or the environment. The perceptual systems of the brain enable individuals to see the world around them as stable, even though the sensory information is typically incomplete and rapidly varying. Perception of objects in the visual world is influenced by features such as shape and colour as well as the meaning and semantic relations among them.16 Chronic experience of social isolation escalates the risk of cognitive deficits.17 Visual and hearing impairments are common with severe mental illness.18


Perception involves attention which is the process of concentrating the mind on a particular task. The process of attention involves several processes including sensory selection, response selection, attentional capacity and sustained performance. The heightened focus during attention increases the ability of the individual to responds speedily and accurately to the interesting stimuli. Attention as a cognitive function is important in controlling and planning for future actions. The capacity to sustain attention over a period of time is impaired in patients with mental illness.


Memory is the ability to encode, store and recall information. Sensory memory is the shortest-term element of memory. Short-term memory is the temporary store required for the current reasoning processes. Storage-oriented memory span tasks with no explicit concurrent processing are usually referred as short-term memory (STM) tasks, whereas tasks involving storage plus concurrent processing requirements are designated as working memory (WM) tasks.19 WM plays a crucial role in many cognitive tasks, such as reasoning, learning and understanding.20 Long-term memory is intended for storage of information over a long period of time. Short-term memories can become long-term memory through the process of consolidation, involving rehearsal and meaningful association. Long-term memory involves a process of physical changes in the structure of neurons (or nerve cells) in the brain. Long-term memory is often divided into two further main types: explicit (or declarative) memory and implicit (or procedural) memory. Declarative memory can be further sub-divided into episodic memory and semantic memory.


Learning as a cognitive function is always discussed in association with memory. Learning is a result of processing and reorganizing information within a matrix of previously acquired information.21

Executive functions

The executive functions are the cognitive functions developed at an advanced level of personality development.22 Prefrontal cortex has the most important role in executive functions. Cognitive control is the primary function of the prefrontal cortex (PFC).23 Inhibitory control and working memory are among the earliest executive functions to develop. Cognitive flexibility, goal-directed behaviour, goal-oriented behaviour and planning are developed at a later stage.   Lezak's model argues that four broad domains of volition, planning, purposive action, and effective performance as working together to accomplish global executive functioning needs.24

Neuroscience of cognitive functions

Cognitive neuroscience explains the chemical and electrical signals produced by neurons in the brain give rise to cognitive processes, such as perception, memory, understanding, insight, and reasoning. Brain areas involved in cognitive functions are limbic system, basal ganglia, dorsolateral prefrontal cortex (DLPFC) and cerebral cortex.25

Cognitive deficits in mental disorders

Historically, the study of the human mind and behaviour are discussed under two categories of cognition and emotion, where emotion is recognized as being inherent to psychiatric disorders, whereas cognitive impairment is comparatively neglected.20  Cognitive deficits are common in schizophrenia and related disorders.26 Cognitive deficits may result in the inability to: pay attention; process information quickly; remember and recall information; respond to information quickly; think critically, plan, organize and solve problems; and initiate speech. Cognitive impairment is a predictor of both overall outcome and specific adaptive deficits.27 There is evidence to suggest that cognitive aging is accelerated in individuals with psychiatric disorders.28 Cognitive symptoms accompany the majority of mental disorders, but are systematically neglected –either under-diagnosed or even ignored. Cognitive deficit is not an illness in itself but a manifestation of an underlying condition. The patient may notice these changes themselves, or most of the time, it is noticed by the caretakers and friends of the patient.29  The patients with cognitive deficits usually have trouble remembering things, difficulty in learning new things and concentrating, process information quickly, respond to information quickly,  vision problems and trouble speaking, as well as difficulty in recognizing people and places.5

Assessment of cognitive deficits

Measurement and Treatment Research to Improve Cognition in Schizophrenia (MATRICS) consensus panel categorised and listed the available neuropsychological assessments measures used in different studies.30 Most commonly used general cognitive assessment measure sare listed below:

When testing cognitive functions the clinician should evaluate memory; visuospatial and constructional abilities; and reading, writing, and mathematical abilities. Abstraction ability is assessed through a patient's performance on tasks, such as proverb interpretation, may be difficult to evaluate when abnormal. Proverb interpretation may be a useful bedside projective test in some patients, but the specific interpretation may result from a variety of factors, such as poor education, low intelligence, and failure to understand the concept of proverbs, as well as a broad array of primary and secondary psychopathological disturbances.14

Management of cognitive deficits

Existing pharmacological and biological treatment modalities fall short to meet the needs to improve the cognitive symptoms.39 There is some evidence suggesting that antipsychotics may partially improve cognitive function, and that this improvement may vary depending on the specific cognitive domain.40 Research evidences suggest that cognitive training/remediation measures improve the functioning, limit disability bettering the quality of life.39 It is also shown that the brain changes with the introduction of new experiences and with the training of new perceptual, cognitive, or motor skills—a process termed neuroplasticity.41 Cognitive training approaches have been applied across various mental illnesses, have used a variety of methods, and study designs, making it currently difficult to integrate findings, draw definitive conclusions, or suggest best practices.41 The management of cognitive deficits is mainly focused on promoting functional status.28 A meta-analysis of 130 randomized, controlled trials of cognitive remediation in schizophrenia including 8851 patients shows that cognitive training produces meaningful benefits in cognition and improves functional outcomes.42

Patients with cognitive deficits are sensitive to their surroundings and seem to do best with optimal stimulation. Understimulation may cause withdrawal; overstimulation may cause confusion and agitation. Familiar and constant surroundings maximize the patient's existing cognitive functions. Daily routines often increase a patient's sense of security; memory and orientation can be facilitated by prominent displays of clocks and calendars, a night light, checklists, and diaries. Medication schedules should be simplified, if possible. If moves cannot be avoided, it helps to place familiar objects (e.g., photographs and furniture) in the new environment and to create a homelike atmosphere. The availability of newspapers, radio, and television can be useful in maintaining a patient's contact with and awareness of the outside world.43

Cognitive training offers considerable promise, especially given the limited efficacy of pharmacological interventions in ameliorating cognitive deficits. The terms cognitive training, cognitive remediation, and cognitive rehabilitation are used both interchangeably and inconsistently in the literature and in clinical practice. Cognitive training aims to drive learning and adaptive neuroplastic changes in an individual’s neural representational systems through specifically defined, neuroscience-based, and controlled learning events. Cognitive training promise as a safe preventive and early intervention for individuals at younger ages and at earlier stages of illness.41 A review of cognitive training in schizophrenia shows that strongest effects is in the global cognition and in the cognitive domains of verbal learning and working memory, followed by lesser effects on attention and processing speed and minimal effects on problem solving and reasoning.44

Role of psychiatric nurse in management of cognitive deficits in patients with mental disorders

Cognitive impairments in individuals with mental disorders result from disease process itself, as a consequence of serious mental disorders, long-term psychopharmacological treatment, and sensory deprivation resulting from hospitalization and social exclusion and isolation secondary to the illness.45,46 Cognitive deficits in mental disorders often keep a stable course in mental disorders. Institutionalized psychiatric patients interact with nursing personal more often than psychiatrist or clinical psychologist. A generalist approach to cognitive deficits can be integrated with routine psychiatric nursing practice. It is vital that psychiatric nursing care of seriously mentally ill patients should focus on preventing cognitive deficits through cognitive and social skills training. Specialized cognitive training or cognitive remediation therapy remains the standard treatment for cognitive deficits in mental disorders.  But scarcity of specialized cognitive remediation therapists deprive a vast majority of psychiatric patients with long-term mental illness.  A more practical, long-term cognitive interventions in collaboration with psychiatric nurses in institutionalized psychiatric setting is a solution for the cognitive deficits seen in psychiatric patients.

The concept of sensory rooms can provide stimulation via sight, smell, hearing, touch and taste in a demand-free environment that is controlled by the patient. The multisensory environment of sensory rooms stimulates sight, smell, hearing, touch and taste. The use of sensory rooms in psychiatric inpatient care is relatively new and understudied.47

Cognitive training can occur in many different ways. It can be in-person with the help of a mental health professional, in one-on-one sessions, in small groups, or in a combination of one-on-one and group sessions. Computerized drill-and-practice or paper-pencil drill-and-strategy training modules are suitable for cognitive training in psychiatric patients.41 There are also a variety of cognitive interventions that are available to do at home without the help of a mental health professional. These programs can be completed on computers, tablets, and other devices. Most cognitive training sessions are between 20 and 60 minutes, up to 5 times a week. Nurses have an important role in cognitive training of patients with mental disorders.


Cognitive functions refers to multiple mental abilities, including learning, thinking, reasoning, remembering, problem solving, decision making, and attention. Cognitive deficits are very common in psychiatric disorders.  Cognition is an important target for treatment in psychiatric illnesses. Cognitive training interventions can result in significant improvements in specific cognitive functions (e.g., memory, attention, and problem solving) across a range of mental illnesses. 


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