Mental health (psychiatric or psychological) conditions involve disturbances in thinking, emotion, and/or behavior. Small disturbances in these aspects of life are common, but when such disturbances cause significant distress to a person and/or interfere with daily life, they are considered mental illnesses. The effects of mental illness may be long-lasting or temporary.
Although tremendous advances have been made in the understanding and treatment of mental illnesses, the stigma surrounding them persists, and health care access is sometimes not the same as for general medical conditions. For example, people with mental illness may feel that they cannot tell anyone about their symptoms or illness or feel they may be blamed for their illness.
Causes of Mental Illness
Currently, mental illness is thought to be caused by a complex interaction of factors, including the following:
Genetic
Biologic (physical factors)
Psychological
Environmental (including social and cultural factors)
Research has shown that for many mental health illnesses, genetics plays a part. Often, a mental illness occurs in people whose genetics makes them vulnerable to such conditions. This vulnerability, combined with life stresses, such as difficulties with family or at work, can lead to the development of a mental illness.
Also, many experts think that impaired regulation of chemical messengers in the brain (neurotransmitters) may contribute to mental health disorders. Brain imaging techniques, such as magnetic resonance imaging (MRI) and positron emission tomography (PET), often show changes in the brains of people with a mental illness. Thus, many mental health conditions appear to have a biologic component, much like disorders that are considered neurologic (such as Alzheimer disease). However, whether the changes seen on imaging tests are the cause or result of the mental health condition is unclear.
Diagnosis of Mental Illness
Mental illness cannot always be clearly differentiated from normal behavior. For example, distinguishing normal grief from depression may be difficult in people who have had a significant loss, such as the death of a spouse or child, because both involve sadness and a depressed mood.
Likewise, deciding whether a diagnosis of anxiety disorder applies to people who are worried and stressed about a stressful work or personal situation can be challenging because most people experience these feelings at some time.
The difference between having certain personality traits (such as being conscientious or orderly) and having a personality disorder (such as obsessive-compulsive personality disorder) can be difficult to determine.
Thus, mental health and mental illness are best thought of as being on a continuum. Any dividing line is usually based on the following:
How severe the symptoms are
How long symptoms last
How much symptoms affect the ability to function in daily life
Classification of mental illness
In 1980, the American Psychiatric Association published the third edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-III), marking the first attempt to approach the diagnosis of mental illness through standardized definitions and criteria. The latest edition, DSM-5-TR, published in 2022, provides a classification system that attempts to separate mental illnesses into diagnostic categories based on descriptions of symptoms (that is, what people say and do as a reflection of how they think and feel) and on the course of the illness.
The International Classification of Disease, 11th Revision, (ICD-11), which was first published by the World Health Organization in 2019, uses diagnostic categories similar to those in the DSM-5-TR. This similarity indicates that diagnoses of specific mental illnesses are becoming more standard and consistent throughout the world.
Social Support
Everyone requires a social network to satisfy the human need to be cared for, accepted, and emotionally supported, particularly in times of stress. Research has shown that strong social support may significantly improve recovery from both general medical conditions and mental illness. In some communities, changes in society have diminished the traditional support once offered by families, neighbors, friends, and coworkers. As an alternative, self-help groups and mutual aid groups exist in many communities. There are also many digital sources of social support, such as virtual support groups. Before joining groups in-person or online, a person should research the group to make sure that it is a good fit, to confirm that it is hosted by an appropriately qualified facilitator or organization, and to ensure safety and privacy.
Some self-help groups, such as Alcoholics Anonymous and Narcotics Anonymous, focus on addiction-related behavior. Others act as advocates for certain segments of the population, such as people with disabilities and older adults. Still others, such as the National Alliance for the Mentally Ill, provide support for family members of people who have a severe mental illness.
Deinstitutionalization
In many countries, there has been a movement since the 1950s to provide care for people with mental illness that supports their ability to live in their own home rather than in an institution (deinstitutionalization). This movement has been made possible by the development of effective medications, providing mental health treatment in community settings whenever medically appropriate, involving various types of health care professionals, and greater acceptance by the general public of people with a mental illness.
Medications to treat mental illness have become more effective and, as a result, the need for being admitted to the hospital or for a lengthy hospitalization has decreased. Many people with mental illness who are admitted to the hospital are discharged within days and continue their care at day treatment centers.
Family members can also support mental health care in the community. Research has shown that certain interactions between a person with severe mental illness and family members can improve or worsen mental illness. Family therapy techniques have been developed that involve family members and prevent people with chronic mental illness from needing to be reinstitutionalized.
Various types of health care professionals play important roles in helping a person with a mental illness to reintegrate into the community. Novel approaches to treatment that help provide a safety net for people with chronic serious mental illness have been developed, such as assertive community treatment (ACT). ACT uses a team of social workers, rehabilitation specialists, counselors, nurses, and psychiatrists. The team provides individualized services to people who have a serious mental illness and who cannot or will not go to a doctor's office or to a clinic for help. The services are provided in the person's own home or neighborhood—for example, in nearby restaurants, parks, or stores.
However, deinstitutionalization has also had many challenges. Replacing the treatment and protection from harm to self or others that can be provided in institutions requires a lot of health care resources, and sufficient resources are not always available. Thus, many people have not been able to get the mental health care and support for food, housing, and other services that they need. People often lack access to health care or are vulnerable to homelessness.
It can become difficult to provide appropriate treatment when a person with a previous serious mental illness becomes ill again. In some places, laws prevent people who are mentally ill but who are not a danger to themselves or society from being treated with medications or admitted to a hospital against their will. Although these laws protect people’s civil rights, they make it more difficult to provide needed mental health care, particularly to people whose mental health conditions that cause them to be unaware that they are ill or to become extremely irrational when left untreated. People who become ill again outside the hospital sometimes become homeless or may be arrested by law enforcement for abnormal behavior.
More Information
The following English-language resource may be useful. Please note that The Manual is not responsible for the content of this resource.
National Alliance on Mental Illness (NAMI): A national mental health organization that provides advocacy, education, support, and public awareness programs and services.
