The term 'anxiety' covers multiple forms of abnormal pathological disorders connected to fear, phobia and nervousness of mind. Anxiety may emerge with sudden manifestation or develop gradually over a period of time that may constitute several years.

The individual suffering from anxiety may fail to fulfill the needs of his/her social life and may falter during normal course of daily routine. Both the fear and anxiety are different phenomenal emotional patterns connected to specific scientific disorders. These two words can hence be used interchangeably. A phobia for instance, which is a state of mental anxiety, stands to be defined as a persistent or irrational fear.

Anxiety is a condition or state in which a human simultaneously experiences multiple emotions of terror, agony and worry. Physically, it is characterized by an increased heartbeat rate, breathlessness, headaches and throbbing pain in the chest region. Anxiety has four different parts or components namely behavioral, emotional, cognitive and somatic.

Description
A trademark behavioral aspect of anxiety is that a person suffering from it, willingly or unwillingly looks to evade its causes or sources. Emotionally, anxieties lead to immense fear and subsequently panic attacks, which occur in situations of extreme anxiety. The cognitive mechanism creates anticipation in humans, similar to animals, of a remote and vague peril.

In the somatic sense the human body automatically readies itself (emergency reaction) to face the danger by increasing the heartbeat rate, blood pressure, sweating and flow of blood to muscles. Also the digestive system and immune system undergo restricted functionality. Visible symptoms of such somatic activity are dilation of pupils, cold shivers and paling of skin.

The Fight/Flight Response
Anxiety is the human body's natural defense mechanism against perceived threat or risk. The scientific term used to describe anxiety is the fight/flight response and is called so as anxiety is always oriented towards either fighting or fleeing the threat.

Nervous Breakdown
Nervous breakdown was called melancholia till the beginning of the 20th century when its name was altered to neurasthenia. The term nervous breakdown was used for the first time around 1930 and is still in usage. Generally, it is indicative of a wide range of mental sickness but more specifically it means breaking,snapping or losing hope in high mental pressure or stress scenarios.

"Nervous breakdown" is not officially a clinical term and doesn't have anything to do with nerves. The closest clinical term to the colloquially called nervous breakdown, is major depression. Depression is caused by biological and genetic factors but can be triggered by environmental and social state of affairs.

Specific examples of triggers are problems in relationships, death of someone close, deception by others, monetary and ego troubles. People having a nervous breakdown lose interest in most activities including daily hygiene care. They always feel tired, energy less, and low without doing absolutely any physical work.