Stress defined as "an internal state which can be caused by physical, social and environmental situations which are an appraisal by the body as potentially harmful and threatening. Here physical, social and environment situations are known as stressors. 

Till 1930, stress was primarily used in the context of engineers and defined merely as a strain on a material object. There is still a  confusion between stress as a "cause" versus "trigger" or stress as a trigger or a response. It has seen that same stressor produce different reactions in the different individual.  This response depends on the coping behaviour of the individual which include defensive behaviour, information seeking behaviour, affiliative behaviour and problem-solving behaviour. The genetic and environmental factor also plays a vital role in determining the stress responses.

Other factors determining the effect of stressor are

1. Nature of stressor: acute or chronic one

2. The frequency of stressor: exposed to a single occasion or multiple times

Body response to the stress

Many systems, including neurotransmitters, (noradrenaline, dopamine and serotonin), hormones (CRH, ACTH,  Cortisol),  and the immune system involved in the manifestation of the stress response of the body. The overall impact of all these systems can be summarised as follows: 

1.  All these effects lead to the development of stress-related disorders, including major depression.

2. They decrease the cellular and innate immunity.

3. They increase the risk of cardiovascular disease like coronary artery disease, myocardial infarction, congestive heart failure.

4. Increases the risk of infections secondary to decrease in immunity.

5. Other illnesses which are influenced by the stress are Atopic dermatitis, Rheumatoid Arthritis, and many Cancer prognoses.

Stress and psychiatric illness

Schizophrenia and other psychotic illness

Stress plays a significant role in the course of schizophrenia. The person with schizophrenia who resides with families with high expressed emotion has doubled relapse rate in comparison with family having low expressed emotions.  Here expressed emotion refers to the attitude of the family member towards the person who has a mental disorder


Stress and depression have a complicated interaction. There is a complex interaction between stress, environment factor and gene which determine the outcome. 

Anxiety Disorder 

Childhood adverse event like abuse, Interpersonal conflicts or serious illness in a close relative may trigger the onset of Panic Disorder and other Anxiety Disorder.

Posttraumatic stress disorder (PTSD) and Acute Stress Disorder (ASD)

PTSD develops after either experiencing or witnessing a life-threatening event or life-altering event.  Its symptoms are flashback, nightmares and severe anxiety and intrusing thought about the event-mostly uncontrollable one.

For further reading about management of stress please read part 2 or visit