What is viewed as normal in one culture may be seen as quite aberrant in another. Thus, notions of normality and abnormality may not be quite as accurate as people believe they are.

An attempt at Distinction:

To bring some amount of clarity to this confusion, I personally prefer to distinguish between mental illness, mental disorder, mental distress and mental ill-being. All of these can be covered under the umbrella term “mental ill-health.

Illness is a state of poor health resulting from disease, and mental illness (commonly known as psychosis) is a state of disruption of mental health caused by neuro-chemical imbalances in the brain that result in behavior that is destructive to self and others.

Thus the mentally ill person begins to lose touch with reality and begins to live in a world of his own mental creation and is unable to function in this world of ours. He/she requires medication to correct the neuro-chemical imbalances in the brain and restore mental health.

The current prevalence estimate in adults is that about 5 percent of the population is affected by mental illness. This category includes illnesses such as schizophrenia, bipolar disorder, and other severe forms of depression; This estimate is stable across geographic and cultural boundaries and gender.

Disorder is defined as “lack of order or regular arrangement”. A condition is a disorder if and only if (a) the condition causes some harm or deprivation of benefit to the person as judged by the standards of the person's culture (the value criterion), and (b) the condition results from the inability of some internal mechanism to perform its natural function. So I prefer to use the term mental disorder to refer to a lack of orderly thinking and emotional instability (commonly known as neurosis) that is caused by unconscious or repressed thoughts and emotions. A person with mental disorder is completely in touch with reality yet finds that he/she experiences mental suffering without being aware of any event that triggered it. They are able to function in this world but not as they would like to. He/she requires professional help to unearth the buried thought / emotion that is triggering the emotional disturbance.

The current adult prevalence estimate is that about 20 to 30 percent of the population is affected by such mental disorders. This category includes illnesses such as severe anxiety, panic, Obsessive-compulsive disorder etc. This estimate also is stable across geographic and cultural boundaries. Features of mental disorders are similar across genders, although diagnosis of the disorders occurs more than twice as often in women as in men.

The prevalence rates for mental illness and mental disorder in children are similar to those of adults

Distress is “ to cause strain, anxiety, or suffering to”. A person has a distress if and only if he has a condition, other than his rational beliefs and desires, such that he is suffering, or at increased risk of suffering, an evil (death, pain, disability, loss of freedom or opportunity, or loss of pleasure) in the presence of a distinct sustaining cause. Thus the term mental distress can be applied to emotions that cause suffering in response to environmental (both internal and external) stimuli. A person with mental distress is in touch with reality, is able to function in this world as he/she would like to but experiences mental suffering in response to some event, that he/she is aware of but is unable to cope with. Removal of the event causing distress or learning to cope with it alleviates the distress

Well-being is defined as “the state of being healthy, and happy”, and the term mental ill-being refers to a feeling of not being quite healthy or happy in the absence of illness, disorder, or distress. A person with mental ill-being is in touch with reality, able to function in this world as he/she would like to, experiences NO mental suffering, yet does not feel quite happy or healthy. Such a person requires to find a meaning or purpose in life.