A disease is a disorder or malfunction of the body, leading to a decline in health. Classifying diseases is seen as a major step in properly identifying and effectively treating diseases. In our previous article, we discovered some categories of conditions and today, we shall learn more.

Degenerative Diseases

As we age, parts of the body work less efficiently. This may happen because the body’s repair mechanisms begin to fail. These failings are associated with characteristics of ageing such as short-term memory loss, poor circulation and reduced mobility.

However, degenerative diseases are not necessarily only associated with growing old. Even in youth or middle age, a gradual loss of function in one or several organs or tissues can occur, associated with progressive destruction of specialized cells. Sometimes this can happen because the body’s defence mechanisms, the immune system, begins to attack the body’s own cells. As degenerative diseases progress, specialized cells are replaced by scar tissue. Deficiencies of nutrients during childhood may be the cause of a degenerative disease later in life by restricting tissues’ full development.

There are three major types of degenerative disease:

• Diseases of the skeletal, muscular and nervous systems, for example, osteoarthritis, muscular dystrophy (also an example of a genetic disease), multiple sclerosis, motor neurone disease and Alzheimer’s disease.

• Cardiovascular diseases

• Cancers

Mental Diseases

When brain tissue starts to degenerate, symptoms of mental decline begin. Sufferers, such as, those with Parkinson’s disease, begin to lose their short-term memory and have difficulty in coordinating and controlling their movements. If untreated, they lose control of basic body functions, suffer severe weakness and become incapable of looking after themselves.

The general decline in all mental faculties is called dementia. This happens in some degenerative diseases, for example, Alzheimer’s and Huntington’s diseases and the spongiform encephalopathies such as Creutzfeldt–Jakob disease (CJD). These affect different areas of the brain, giving rise to different signs and symptoms. Multiple blockages of blood vessels in the brain due to arteriosclerosis is the most common cause of dementia.

Many mental diseases are not associated with widespread degeneration of the brain. Mild personality disorders are also classified as a mental disease. These are disorders of the mind-affecting thoughts, feelings, emotions and personal and social behaviour.

Mental diseases are categorized into two groups:

• Neurones or mild disorders such as anxiety states, for example, claustrophobia, agoraphobia and other phobias. These are not associated with any physical malfunction or damage to the brain.

• Psychoses, which are severe disorders that prevent people functioning in a normal manner, for example, schizophrenia and manic depression. The causes are unknown but are likely to be associated with physical damage or a malfunction of the brain’s neurotransmitters.

Social Diseases

Social Factors contribute to the spread of disease. Aspects of the physical environment, such as standards of housing, sanitation, pollution and access to recreational facilities are important. Social class, poverty, and occupation can put people at risk of developing certain acute and chronic diseases, for example, glass-blowers and silicosis.

Poverty and poor living conditions can encourage disease. For example, infectious diseases tend to spread more easily in overcrowded, unsanitary and unhygienic conditions. Obesity and cardiovascular diseases such as CHD are more common in affluent countries, but within these countries, people in the lower socio-economic groups are afflicted most.

This disease category can be interpreted very widely to include almost all the infectious diseases and the multifactorial diseases that are influenced by people’s living conditions and personal behaviour.

Self-Inflicted Diseases

Self-inflicted diseases are those in which people’s health is put at risk by their own decisions regarding their behaviour. Those who start smoking at a young age are highly likely to become addicted to nicotine. One study in the UK showed that smoking could kill or cause harm in 24 different ways. For example, it is a major contributory factor to lung cancer, chronic bronchitis, emphysema, high blood pressure and gangrene. Smoking during pregnancy can lead to a mother having an underweight baby. Misusing other drugs such as alcohol and heroin can lead to drug dependence, which puts the person at risk of developing a variety of physical and mental diseases.

Deliberate self-harm such as taking an overdose of tablets in an attempted suicide, could also be considered a form of the self-inflicted disease as there is often permanent damage to major body organs.

What is your perspective about these diseases? Please share your comments!