It may be difficult for many to define what exactly comprises mental illness. We think the Swedish public health agency’s description is very good and can be read below.
This is a picture that shows how the concepts overlap. Mental health and mental illness can occur simultaneously.
The WHO defines mental health as a state of mental well-being in which each individual can realize their own opportunities, can cope with common stress, can work productively and can contribute to the society in which he or she lives. Mental health thus includes something more than the absence of mental illness, and includes both the individual’s experience and the relationship between the individual and the social context in which he or she lives.
Mental illness is often used as an overall term that covers both mental disorders and mental illness. The concept of mental illness includes various forms of mental problems and also clinically defined disease states.
Mental problems describe various conditions when people show signs of mental imbalance or symptoms such as worry, anxiety, depression, or difficulty sleeping. Depending on the type and scope, mental problems can affect functional ability to varying degrees. The symptoms are not so extensive that diagnosis can be made, and are usually normal reactions to a stressful life situation.
Mental illness is a condition where several symptoms meet the criteria for a diagnosis. Mental illness is currently defined on the basis of diagnostic criteria in international diagnostic systems. Two established diagnostic systems are the WHO International Classification of Diseases (ICD) and the American Psychiatric Association, which is behind the Diagnostic and Statistical Manual of Mental Disorders (DSM).