Migraine

This chapter examines migraine. The incidence of migraine varies depending on multiple aspects, including age, sex, and the presence of aura. At an earlier age (younger than age ten), migraine initially affects more boys than girls, with migraine with aura (MA) occurring at a younger age than migraine without aura (MO). Later in life, when puberty starts, this relationship changes and it becomes more common in women than men. Migraine aura are focal neurological symptoms that typically occur prior to the onset of a headache due to a phenomenon called cortical spreading depression. The prevalence of migraine with aura vary between visual, sensory, or motor symptoms. It can also present as diplopia, slurred speech, aphasia, dizziness, vertigo, and hemiparesis. Moreover, the prevalence of migraine varies according to headache frequency. The chapter then looks at chronic migraine and menstrual migraine. It also explores several comorbidities associated with migraine, including many neurologic, medical, and psychiatric conditions.

Small vessel disease

‘Small vessel disease’ describes a combination of neuroradiological and clinical features that are due to an intrinsic disorder of the small cerebral arterioles, capillaries, and venules in varying proportions. It is very common, usually sporadic, although rare monogenic forms are well described. The commonest presentations are with stroke or cognitive impairment. The cause of the small vessel abnormalities in the sporadic form is not well understood and the brain damage is generally attributed to ischaemia secondary to the vessel abnormality. However, evidence for altered microvessel function and blood brain barrier failure is accumulating. The commonest risk factors are increasing age, hypertension, smoking, and diabetes, but environmental and lifestyle factors are also important although poorly understood. Whether the imaging features or incidence of small vessel-related stroke or dementia vary by world region is unknown. We review current knowledge on presentation, aetiology, incidence, and prevalence of sporadic small vessel disease.

Behavioural and psychological symptoms of dementia

The term: ‘behavioural and psychological symptoms of dementia’ (BPSD) refers to a mixed group of phenomena. BPSD are the non-cognitive features of dementia and include depression, anxiety, psychotic symptoms, apathy, irritability, aggression, and sleep and eating problems. They occur in around 80% of people with dementia at some stage, several of them becoming more frequent as dementia progresses. Some BPSD, notably apathy, are very persistent. BPSD often limit the person’s quality of life and can be stressful for carers. Causes of BPSD include biological, psychological, social, and environmental factors. This chapter explores how they are assessed and measured, and how they may usefully grouped together in symptom clusters. Usually four symptom groups are found: affective symptoms, psychosis, hyperactivity, and euphoria. However, these are not always consistent and in particular apathy does not consistently belong in one group. Approaches to management of BPSD are outlined.

Epidemiology of schizophrenia and related disorders

Epidemiological approaches to understanding the frequency, distribution, and determinants of psychotic disorders, such as schizophrenia, have played a vital role in delineating the aetiology and course of these conditions for almost a century. Despite several milestones, reviewed in this chapter, many methodological and clinical aspects of these disorders continue to provide challenges to studying the epidemiology of psychotic disorders, including issues of case definition, case ascertainment, and study design. After summarizing these challenges, we review the current neuropsychiatric epidemiologic knowledge of the incidence, prevalence, and aetiology of psychotic disorders. Here, we also provide a contemporary overview of the role that genetic, neurodevelopmental, demographic and environmental risk factors, including inflammation, traumatic life events, substance abuse, urban living, and minority status have on risk, course, and outcome of psychotic disorder. We conclude with future directions required to elucidate the interplay of these factors in contributing to the global burden of psychotic disorders.

A historical perspective on neurological and neuropsychiatric definitions

Taking a historical epistemological perspective, this chapter explores how neurology and neuropsychiatry were constructed. As a medical specialism developing in the 19th century, neurology resulted from the convergence of: (1) the term ‘neurology’; (2) a set of concepts; and (3) a list of disorders. Such a convergence was facilitated by changes in the manner in which the concepts of neuroses, central nervous system, and lesion were to be defined after 1860. Neuropsychiatry carries a less stable epistemology. Underpinned by the foundational claim that mental diseases are diseases of the brain, its meaning has changed pari passu with redefinitions of the concepts such as mind, mental symptom, cause, and meaning. In the UK, there is no agreed definition of neuropsychiatry either and hence what is currently known as ‘organic/biological psychiatry’ and the claim that psychiatry is just a subregion of neurology cannot be considered as coterminous.

The neuroepidemiology of human prion disease

Human prion diseases comprise a number of rare and fatal neurodegenerative conditions that result from the accumulation in the central nervous system of an abnormal form of a naturally occurring protein, called the prion protein. The diseases occur in genetic, sporadic, and acquired forms: genetic disease is associated with mutations in the prion protein gene (PRNP); sporadic disease is thought to result from a spontaneous protein misfolding event; acquired disease results from transmission of infection from an animal or another human. The potential transmissibility of the prion in any of these forms, either in disease states or during the incubation period, has implications for public health. Here we focus on Creutzfeldt-Jakob Disease (CJD), including variant Creutzfeldt-Jakob Disease (vCJD), although we will also discuss other forms of human prion disease.

Delirium

Delirium is a common and severe neuropsychiatric syndrome of brain dysfunction characterized by acute and fluctuating inattention and other cognitive and perceptual deficits precipitated by acute illness. Despite being first described by Hippocrates more than two thousand years ago, there exists considerable uncertainty regarding the diagnosis of delirium due to our limited understanding of fundamental concepts, including its definition and pathophysiology. The ensuing lack of standardization results in delirium being frequently undiagnosed and significant misclassification bias in existing research. This chapter discusses the descriptive epidemiology of delirium, including methodological issues around case ascertainment in different population and clinical settings. There remains a lack of epidemiological research in the field, but we indicate the potential for observational longitudinal studies to address key questions on the population impact of delirium alongside fundamental questions of major importance to patients and their families regarding outcomes after delirium.

Cardiometabolic morbidities and dementia

Cardiometabolic morbidities and dementia are increasingly common as people age. In this chapter, we summarize the epidemiological literature concerning: (1) mixed dementia due to cerebrovascular and neurodegenerative lesions as the most common form of dementia in older people; (2) the relation of cardiovascular disease with cognitive decline and dementia and the underlying pathophysiological mechanisms; and (3) cardiovascular comorbidities in dementia and impact on dementia care and prognosis. Atherosclerotic and arteriosclerotic disorders resulting from long-term exposures to cardiovascular risk factors, together with neurodegeneration in brain ageing, contribute to accelerated cognitive decline and dementia. The heart-brain connection in ageing has implications for dementia interventions. Furthermore, cardiovascular comorbidities in dementia contribute to poor outcomes, create complex challenges for dementia care, and substantially increase social care costs of dementia. Thus, early recognition and management of cardiovascular comorbidities in dementia may help health and social care providers maximize the well-being of people with dementia.

What is the role of trials and other ‘well-designed’ studies in the understanding of neurological and neuropsychiatric conditions

This chapter lays out a brief summary of the ways in which we bring our contemporary and past knowledge of disorders together in a way that can integrate impact for society. The value of diagnosis can be viewed from different perspectives and sectors of any particular society. There have been many changes to the definitions of many, if not most, disorders and diseases affecting human populations due to changing biologies and new methods of investigation. This includes change in diagnostic approaches and definitions, the approaches currently used in Global Burden of Disease and Health Life Expectancies as well as public health approaches to bringing together evidence about primary, secondary, and tertiary prevention.

The oldest-old and dementia at the end of life

The oldest-old and dementia at the end of life describes what is known about the prevalence, incidence, and risk factors for dementia in people aged 90 and older, the fastest growing segment of the population in much of the world. It reviews the main neuropathological abnormalities found during autopsy, including Alzheimer’s disease (AD), vascular lesions, and hippocampal sclerosis and discusses how these abnormalities are related to dementia in very elderly individuals. The chapter highlights differences in risk and protective factors, and underlying neuropathologies associated with dementia compared to younger elderly. Taking into consideration the rapid increase in the number of oldest-old by the middle of the century, it reviews the potential impact of interventions to reduce Alzheimer’s disease pathology on the prevalence of dementia in this age group. Finally, it presents methodological challenges in studying this age group and offers potential strategies to address some of these challenges.