The sensation of vision arises from the detection of photons of light at the eye, but in order to produce the percept of the world, extensive regions of the brain are required to process the visual information. The majority of information entering the brain via the optic nerve from the eye projects via the lateral geniculate nucleus (LGN) of the thalamus to the primary visual cortex, the largest visual area, having been reorganized such that one side of the brain represents one side of the world.
Damage to the primary visual cortex in one hemisphere therefore leads to a loss of conscious vision on the opposite side of the world, known as hemianopia. Despite this cortical blindness, many patients are still able to detect visual stimuli that are presented in the blind region if forced to guess whether a stimulus is present or absent. This is known as “blindsight.” For patients to gain any information (conscious or unconscious) about the visual world, the input from the eye must be processed by the brain. Indeed, there is considerable evidence from functional brain imaging that several visual areas continue to respond to visual stimuli presented within the blind region, even when the patient is unaware of the stimulus. Furthermore, the use of diffusion imaging allows the microstructure of white matter pathways within the visual system to be examined to see whether they are damaged or intact. By comparing patients who have hemianopia with and without blindsight it is possible to determine the pathways that are linked to blindsight function. Through understanding the brain areas and pathways that underlie blindsight in humans and non-human primates, the aim is to use modern neuroscience to guide rehabilitation programs for use after stroke.
Depression is defined in diagnostic literature as a mood disorder characterized by depressed mood, loss of interest or pleasure in activities, significant changes in weight, insomnia or hypersomnia, psychomotor agitation or retardation, fatigue or loss of energy, feelings of worthlessness or excessive guilt, difficulty concentrating, and suicidal ideation and/or attempts. Research suggests a link between depressed mood and monoamine depletion, elevated cortisol, and inflammation, but existing laboratory evidence is inconclusive. Current treatments for depression include selective serotonin reuptake inhibitors (SSRIs), cognitive behavioral therapy (CBT), and lifestyle changes; however, more severe forms of the disorder can require other medication, sometimes in combination with electroconvulsive therapy (ECT).
Disagreement persists over how to define and classify depression, in part due to its ambivalent relationship to melancholia, which has existed as a medical concept in different forms since antiquity. Melancholia was reconfigured in 19th-century medicine from traditional melancholy madness into a modern mood disorder. In the early 20th century, melancholia gradually fell out of use as a diagnostic term with the introduction of manic-depressive insanity and unipolar depression. Following the publication of DSM-III in 1980 and the introduction of SSRIs a few years later, major depressive disorder became ubiquitous. Consumption of antidepressants have continued to rise year after year, and the World Health Organization notes depression as the leading cause of disability worldwide.
At present, internationally recognized systems of classification favor a single category for depressive illness (alongside a circular mood disorder, bipolar I and II), but this view is challenged by clinicians and researchers who argue for the reinstatement of melancholia as a separate and distinct mood disorder with marked somatic and psychotic features.
Scott O. Lilienfeld and Candice Basterfield
Evidence-based therapies stemmed from the movement toward evidence-based medicine, and later, evidence-based practice (EBP) in psychology and allied fields. EBP reflects a progressive historical shift from naïve empiricism, which is based on raw and untutored observations of patient change, to systematic empiricism, which refines and hones such observations with the aid of systematic research techniques. EBP traces its roots in part to the development of methods of randomization in the early 20th century. In American psychology, EBP has traditionally been conceptualized as a three-legged stool comprising high-quality treatment outcome evidence, clinical expertise, and patient preferences and values. The research leg of the stool is typically operationalized in terms of a hierarchy of evidentiary certainty, with randomized controlled trials and meta-analyses of such trials toward the apex. The most influential operationalization of the EBP research leg is the effort to identify empirically supported treatments, which are psychotherapies that have been demonstrated to work for specific psychological conditions. Still, EBP remains scientifically controversial in many quarters, and some critics have maintained that the research base underpinning it is less compelling than claimed by its proponents.
Psychosomatics concerns those physical disorders not caused by an organic event but caused by psychological events. These disorders, called “psychosomatic,” may involve different organs and systems and it is possible a wide range of cases of possible psychosomatic disorders.
The term psychosomatics itself represents all the complexity and tension of this discipline. It contains a dualism that contrasts with the theory at the heart of psychosomatic medicine—the functional and synergistic unitary nature of soma and psyche.
The psychosomatic problem represents the original nucleus at the inception of the psychoanalytic movement that concerns itself precisely with the physical disorders devoid of an anatomopathological substratum. With the development of the libido theory and the resulting hypotheses on the development of neurosis, Freud proposed a model that integrates the somatic, psychic, and social component, and it represents in a convincing way physical diseases that occur as a result of psychological events. Freud created two distinct approaches in the explanation of psychosomatic disorders: the first makes use of a system of conversion of the psychic into the somatic, and the second raises problems of biological nature, in the sense that a psychological factor (anxiety) would directly activate the sympathetic system and therefore the organic functions it controls.
The conflict theory was the first major paradigm of psychosomatic medicine, and most efforts by the first generation of psychosomatists aimed to test this hypothesis and identify psychological conflicts that were typical of patients suffering from diseases considered psychosomatic in nature. Some scholars—such as Federn, Goddeck, Deutsch, Dumbar and Alexander, Schultz-Hencke, von Weizsäcker, Schilder, Schur, de Mitsherlich, de Boor—starting from the Freudian psychoanalysis, emphasize a particular psychoanalytic mechanism interpreted as a cause of psychosomatic disorders. The panorama of contemporary psychosomatics is certainly much more varied than the classical one, and new proposals and conceptions have emerged alongside the psychoanalytic model. The main contemporary models aim to integrate the knowledge of medicine and psychoanalysis into a coherent and unitary theoretical whole. The goal is therefore the unification of the ontological and scientific dualism that sees the body of medicine as opposed to the psyche of psychoanalysis. The contemporary theories all converge in the analysis of the original mechanisms of formation and development of subjectivity that is named according to the search to address ego, self, or identity.
The idea that suppressing an unwanted thought results in an ironic increase in its frequency is accepted as psychological fact. Wegner’s ironic processes model has been applied to understanding the development and persistence of mood, anxiety, and other difficulties. However, results are highly inconsistent and heavily influenced by experimental artifact. There are a substantial number of methodological considerations and issues that may underlie the inconsistent findings in the literature. These include the internal and external validity of the paradigms used to study thought suppression, conceptual issues such as what constitutes a thought, and consideration of participants’ history with and motivation to suppress the target thought. Paradigms that study the products of failed suppression, such as facilitated recall and attentional deployment to thought relevant stimuli may have greater validity. It is argued that a shift from conceptualizing the persistence of unwanted thoughts as products of failed suppression and instead as internal threat stimuli may have merit.
Sleep health is understood as a key factor in lifelong health and for social participation, function, and satisfaction. In later life, insomnia and other sleep disturbances are common. Insomnia is experienced as poor, disrupted, or insufficient sleep associated with significant daytime impairments including increased fatigue or reduced energy, impaired cognitive function, and increased mood disturbance. Poor sleep is associated with negative outcomes across a range of dimensions that impair quality of life, increases risk for other diseases, and may interact negatively with the progression and treatment of other disorders. Evidence for effective psychological interventions to improve sleep in later life, specifically cognitive behavioral therapy for insomnia, is robust and well described. Good sleep should be understood as a substrate for psychological health and a reasonable expectation in later life.
Benjamin Gardner and Amanda L. Rebar
Within psychology, the term habit refers to a process whereby contexts prompt action automatically, through activation of mental context–action associations learned through prior performances. Habitual behavior is regulated by an impulsive process, and so can be elicited with minimal cognitive effort, awareness, control, or intention. When an initially goal-directed behavior becomes habitual, action initiation transfers from conscious motivational processes to context-cued impulse-driven mechanisms. Regulation of action becomes detached from motivational or volitional control. Upon encountering the associated context, the urge to enact the habitual behavior is spontaneously triggered and alternative behavioral responses become less cognitively accessible.
By virtue of its cue-dependent automatic nature, theory proposes that habit strength will predict the likelihood of enactment of habitual behavior, and that strong habitual tendencies will tend to dominate over motivational tendencies. Support for these effects has been found for many health-related behaviors, such as healthy eating, physical activity, and medication adherence. This has stimulated interest in habit formation as a behavior change mechanism: It has been argued that adding habit formation components into behavior change interventions should shield new behaviors against motivational lapses, making them more sustainable in the long-term. Interventions based on the habit-formation model differ from non-habit-based interventions in that they include elements that promote reliable context-dependent repetition of the target behavior, with the aim of establishing learned context–action associations that manifest in automatically cued behavioral responses. Interventions may also seek to harness these processes to displace an existing “bad” habit with a “good” habit.
Research around the application of habit formation to health behavior change interventions is reviewed, drawn from two sources: extant theory and evidence regarding how habit forms, and previous interventions that have used habit formation principles and techniques to change behavior. Behavior change techniques that may facilitate movement through discrete phases in the habit formation trajectory are highlighted, and techniques that have been used in previous interventions are explored based on a habit formation framework. Although these interventions have mostly shown promising effects on behavior, the unique impact on behavior of habit-focused components and the longevity of such effects are not yet known. As an intervention strategy, habit formation has been shown to be acceptable to intervention recipients, who report that through repetition, behaviors gradually become routinized. Whether habit formation interventions truly offer a route to long-lasting behavior change, however, remains unclear.
Kim Van Orden, Caroline Silva, and Yeates Conwell
Suicide in later life is a significant public health problem around the world—a problem that will increase in magnitude in the coming years with the impact of population aging. Adults age 70 and older have higher suicide rates than younger groups worldwide in both lower-income and higher-income countries. While suicide rates tend to increase with age, suicide in later life is not an expected or normative response to stressors that accompany the aging process. Instead, a constellation of risk factors places an older adult at elevated risk for suicide. These factors can be remembered as the Five D’s: psychiatric illness (primarily
Nadeeka N. Dissanayaka
Progressive neurological disorders are incurable disorders with gradual deterioration and impacting patients for life. Two common progressive neurological disorders found in late life are Parkinson’s disease (PD) and motor neuron disease (MND). Psychological complications such as depression and anxiety are prevalent in people living with PD and MND, yet they are underdiagnosed and poorly treated.
PD is classified a Movement Disorder and predominantly characterized by motor symptoms such as tremor, bradykinesia, gait problems and postural instability; however, neuropsychiatric complications such as anxiety and depression are common and contribute poorly to quality of life, even more so than motor disability. The average prevalence of depression in PD suggest 35% and anxiety in PD reports 31%. Depression and anxiety often coexist. Symptoms of depression and anxiety overlap with symptoms of PD, making it difficult to recognize. In PD, daily fluctuations in anxiety and mood disturbances are observed with clear synchronized relationships to wearing off of PD medication in some individuals. Such unique characteristics must be addressed when treating PD depression and anxiety. There is an increase in the evidence base for psychotherapeutic approaches such as cognitive behavior therapy to treat depression and anxiety in PD.
Motor neuron disease (MND) is classified a neuromuscular disease and is characterized by progressive degeneration of upper and lower motor neurons is the primary characteristic of MND. The most common form of MND is Amyotrophic lateral sclerosis (ALS) and the terms ALS and MND are simultaneously used in the literature. Given the short life expectancy (average 4 years), rapid deterioration, paralysis, nonmotor dysfunctions, and resulting incapacity, psychological factors clearly play a major role in MND. Depression and suicide are common psychological concerns in persons with MND. While there is an ALS-specific instrument to assess depression, evaluation of anxiety is poorly studied; although emerging studies suggesting that anxiety is highly prevalent in MND. Unfortunately, there is no substantial evidence-base for the treatment of anxiety and depression in MND.
Caregivers play a major role in the management of progressive neurological diseases. Therefore, evaluating caregiver burden and caregiver psychological health are essential to improve quality of care provided to the patient, as well as to improve quality of life for carers. In progressive neurological diseases, caregiving is often provided by family members and spouses, with professional care at advanced disease. Psychological interventions for PD carers addressing unique characteristics of PD and care needs is required. Heterogeneous clinical features, rapid functional decline, and short trajectory of MND suggest a multidisciplinary framework of carer services including psychological interventions to mitigate MND. A Supportive Care Needs Framework has been recently proposed encompassing practical, informational, social, psychological, physical, emotional, and spiritual needs of both MND patients and carers.
Simon J. Haines, Jill Talley Shelton, Julie D. Henry, Gill Terrett, Thomas Vorwerk, and Peter G. Rendell
Tasks that involve remembering to carry out future intentions (such as remembering to attend an appointment), and the cognitive processes that enable the completion of such tasks (such as planning), are referred to as prospective memory (PM). PM is important for promoting quality of life across many domains. For instance, failures in remembering to meet social commitments are linked to social isolation, whereas failures in remembering to fulfill occupational goals are linked to poorer vocational outcomes. Declines in PM functioning are of particular concern for older adults because of the strong links between PM and functional capacity. The relationship between age and PM appears to be complex, dependent on many factors. While some aspects of PM appear to hold up relatively well in late adulthood, others appear to show consistent age-related decline. Variability in age differences appears to partially reflect the fact that there are diverse types of PM tasks, which impose demands on a range of cognitive processes that are differentially affected by aging. Specifically, the level and type of environmental support associated with different PM task types appears to be a meaningful determinant of age-related effects. Given the worldwide changing age demographics, the interest in age-related effects on PM will likely intensify, and a primary focus will be how to optimize and maintain PM capacity for this population. This is already reflected in the increasing research on interventions focused on enhancing PM capacity in late adulthood, and points to important future directions in this area of study.