Illness
Illness (sometimes referred to as ill-health) can  be defined as a state of poor health.

# Introduction
The mode of being healthy includes, as defined by the World Health Organization, "  a state of complete physical, mental and social well-being and not merely the absence of disease or infirmity" (WHO, 1946). When these conditions are not fulfilled, then one can be considered to have an illness or be ill. Medication and the science of pharmacology is used to cure or reduce symptoms of an illness or medical conditions. Developmental disability is a term used to describe severe, life-long disabilities attributable to mental and/or physical impairments.

# Physical being
Abnormal conditions of the body or mind that cause discomfort, dysfunction, or distress to the person afflicted or those in contact with the person can be deemed an illness. Sometimes the term is used broadly to include injuries, disabilities, syndromes, infections, symptoms, deviant behaviors, and a typical variations of structure and function, while in other contexts these may be considered distinguishable categories. A pathogen or infectious agent is a biological agent that causes disease or illness to its host. A passenger virus is a virus that simply hitchhikes in the body of a person or infects the body without causing symptoms, illness or disease. Foodborne illness or food poisoning is any illness resulting from the consumption of food contaminated with pathogenic bacteria, toxins, viruses, prions or parasites.

# Mental being
Mental illness (or Emotional disability, Cognitive dysfunction) is a broad generic label for a category of illnesses that may include affective or emotional instability, behavioral dysregulation, and/or cognitive dysfunction or impairment.  Specific illnesses known as mental illnesses include major depression, generalized anxiety disorder, schizophrenia, and attention deficit hyperactivity disorder, to name a few. Mental illness can be of biological (e.g., anatomical, chemical, or genetic) or psychological (e.g., trauma or conflict) origin. It can impact ones ability to work or go to school and contribute to problems in relationships. Other generic names for mental illness include mental disorder, psychiatric disorder, psychological disorder, abnormal psychology, emotional disability, emotional problems, or behavior problem. The term insanity is used technically as a legal term. Brain damage may occur due to a wide range of conditions, illnesses, or injuries.
A delusion is commonly defined as a fixed false belief and is used in everyday language to describe a belief that is either false, fanciful or derived from deception. In psychiatry, the definition is necessarily more precise and implies that the belief is pathological (the result of an illness or illness process).  In the Munchausen syndrome, the sufferer feigns, exaggerates, or creates symptoms of illnesses in himself or herself in order to gain investigation, treatment, attention, or sympathy. Munchausen syndrome by proxy often involves inducing illness in another to the same end.
Mental health consumer is a person who is under treatment for a psychiatric illness or disorder. The term was coined in an attempt to empower those with mental health issues, usually considered a marginalized segment of society. The term suggests that those individuals have a choice in their treatment and that without them there could not exist mental health providers.

# Social being
Social determinants of health are the social conditions in which people live which determine their health. Illnesses are generally related to social, economic, political, and environmental circumstances. Social determinants of health have been recognized by several health organizations such as the Public Health Agency of Canada and the World Health Organization to greatly influence collective and personal well-being.

# Treatments
The governmental involvement is vital and may also be required to study a range of illnesses and treatments. Health care is the prevention, treatment, and management of illness and the preservation of mental and physical well-being through the services offered by the medical, nursing, and allied health professions. The organised provision of such services may constitute a health care system. Before the term "healthcare" became popular, English-speakers referred to medicine or to the health sector and spoke of the treatment and prevention of illness and disease. A patient is any person who receives medical attention, care, or treatment. The person is most often ill or injured and is being treated by, or in need of treatment by, a physician or other medical professional. Health consumer or health care consumer is another name for patient, usually used by some governmental agencies, insurance companies, and/or patient groups.
Medical emergencies are injuries or illnesses that pose an immediate threat to a person's health or life which require help from a doctor or hospital. The doctor's specialization of emergency medicine includes techniques for effective handling of medical emergencies and resuscitation of patients. Emergency departments provides initial treatment to patients with a broad spectrum of illnesses and injuries, some of which may be life-threatening and requiring immediate attention.
A drug is any chemical substance other than a food or device that affects the function of living things. Drugs can be used to treat illness, or they can be used recreationally to alter behavior and perception. Medications are typically produced by pharmaceutical companies and are often patented. Those that are not patented are called generic drugs. Some physicians can prescribe approved medications for other than their intended indications, referred as "Off-label use". Marketing information for the drug will list one or more indications, i.e., illnesses or medical conditions for which the drug has been shown to be both safe and effective. A drug overdose occurs when a chemical substance (i.e. drug) is ingested in quantities and/or concentrations large enough to overwhelm the homeostasis of a living organism, causing severe illness or death. Essentially it is a type of poisoning. In the context of biology, poisons are substances that can cause illness.
Bedrest as a medical treatment refers to staying in bed day and night as a treatment for a hangover. Even though most patients in hospitals spend most of their time in the hospital beds, bedrest more often refers to an extended period of recumbence at home.
Human enhancement technologies (HET) are technologies that can be used not simply for treating illness and disability, but also for enhancing human capacities and characteristics. Medication is a licenced drug taken to cure or reduce symptoms of an illness or medical condition.  A wheelchair is mobility device that takes the form of a chair on wheels, used by people for whom walking is difficult or impossible due to illness or disability.
Shock therapy is the deliberate and controlled induction of some form of physiological state of shock in an individual for the purpose of psychiatric treatment. Electrotherapy is the use of electrical energy in the treatment of impairments of health and a conditions of abnormal functioning.

# Medical activities
Epidemiology is the scientific study of factors affecting the health and illness of individuals and populations, and serves as the foundation and logic of interventions made in the interest of public health and preventive medicine.
Behavioral medicine is an interdisciplinary field of medicine concerned with the development and integration of psychosocial, behavioral and biomedical knowledge relevant to health and illness. Clinical Global Impression scale to assess treatment response in patients with mental disorders. It's " Improvement scale" requires the clinician to rate how much the patient's illness has improved or worsened relative to a baseline state. Mental confusion and decreased alertness may indicate that a chronic illness has gotten worse.