Alcohol. Alcohol is a powerful drug.

It contains ethanol, the most common type of alcohol that helps to reduce tension and inhibition in a person.

It works by dilating small blood vessels near the skin hence causing the person to become red, warm and feel comfortable.

Initially, the alcohol affects the brain's motor center, cerebellum and the medulla oblongata resulting in a person's poor coordination and balance, sluggish reflexes, change in behavior, and loss of memory, slowing of speech, increased rate of heartbeat and breathing.

Large amounts of alcohol can even lead to coma or death.

Long-term effects for the alcohol addicts include malnutrition and damage to heart muscles, stomach disorders like ulcers and gastritis, the liver is not able to detoxify blood or process nutrients due to liver cirrhosis.

Other medicines interact negatively with alcohol so any side medication can be harmful.

Social and personal problems in life are likely to happen due to the addiction.

If consumed during pregnancy, fetal abnormalities and miscarriages can occur such as reduced physical and mental development, mental retardation, birth defects.

Driving while intoxicated is illegal worldwide.

Alcohol consumption slows reflex time and blurs the vision of the driver.

This would then lead to an overall poor judgment of the driver, resulting in fatal road accidents.

Tobacco. Tobacco smoking is habit-forming.

The smoke drawn into the lung consists of nicotine, carbon monoxide, tar and other harmful substances.

This is why there is a strong link between the act of smoking and respiratory diseases.

Nicotine is a stimulant found commonly in tobacco and is responsible for causing most of the chemical changes in the body.

Short-term effects of tobacco smoking include an increased heart rate and blood pressure.

Tar in the smoke affects the mucous membranes of respiratory systems.

This is why smokers cough because they try to clear their respiratory tract.

Carbon monoxide damages the lining of blood vessels while increasing fatty deposits on the walls.

Nicotine causes blood vessels to constrict which leads to heart diseases.

In small amounts, it stimulates the adrenal gland to be active.

Smokers may feel nervous and tense for no reason.

New smokers can experience nicotine poisoning, whose symptoms include dizziness, vomiting, clammy skin and even fainting spells.

The long-term use of tobacco smoking can cause breathing problems like bronchitis, asthma, emphysema, heart disease and lung cancer.

Emphysema causes thinning or destruction of alveoli in our lungs.

Tar stains teeth and fingers and can deposit in the lungs, leading to growth of cancerous cells.

Other chemical irritants in the smoke cause narrowing of air passages.

Smoke addiction may lead to social and personal problems.

If the addicts are pregnant women, babies are smaller at birth and there is an increased risk of miscarriage, still birth and infant death.