Underlying Causes of Mental Illness

The exact causes of most identified health mental disorders are not well understood.

What Is Mental Illness?

Mental illness, or a mental health disorder, is a type of psychological syndrome or behavioral pattern that is associated with an increased risk of disability, suffering, pain, or loss of freedom to act independently.

In the United States, the American Psychiatric Association (APA) lists the diagnosable forms of mental illness in their Diagnostic and Statistical Manual of Mental Disorders – Fifth Edition (DSM-5).

The underlying causes of mental illness are very complex. They will vary depending on the particular type of mental illness and the person who is expressing it.

General Theories of the Causes of Mental Illness

Although the DSM-5 classifies different forms of mental illness, it does not speculate on their causes. There have been many different models that have attempted to explain the causes of mental health disorders. Many of these models have lost favor today.

The book What is Mental Illness? outlines some of these theories.

  • Dysfunctional parent-child relationships: During a good part of the 20th century, mental illness was believed to be the result of dysfunctional relationships between parents and their children. The view was popularized by theorists like Sigmund Freud, and it was strongly supported in the late part of the 1900s.It is still believed that dysfunctional relationships between parents and children can contribute to the risk of developing mental illness, but it is no longer considered to be the only underlying cause of mental illness.
  • Biological/biomedical models: A view that remains popular today, especially in psychiatry, is that mental illness is a result of some type of brain dysfunction, such as an imbalance of neurotransmitters or some genetic influence. Psychiatrists are medical doctors who primarily attempt to treatment illness with medicines, so this model fits their approach. However, there is very little research evidence that can definitively determine any biological cause for most forms of mental illness.
  • Biopsychosocial model: The current model that is generally accepted by many theorists and researchers merges biology, psychology, and social factors into the potential cause of most forms of mental illness. This means that many forms of mental illness have a genetic predisposition, but this is only activated if certain psychological and social factors influence it.For example, if a researcher determines that heredity accounts for about 30 to 40 percent of a person’s susceptibility to developing a particular mental health disorder, then psychological and social factors must account for the other 60 to 70 percent. The model is based on the notion that environment affects biology, and biology (heredity) also affects the environment.

Other Specific Causes & Effects

According to Madness: An American History of Mental Illness and Its Treatment, there are other potential causes of specific types of mental health disorders.

  • Infection, disease, or toxin exposure: Some forms of mental illness have been linked to infections, diseases, or exposure to toxins. For instance, the risk of developing attention deficit hyperactivity disorder (ADHD) is increased in infants who are exposed to alcohol in the womb.
  • Prenatal insults: Other prenatal insults that damage the fetus may be at least partially responsible for certain types of mental health disorders, such as autism.
  • Brain defects or other injuries: Head trauma can be associated with certain types of neurocognitive disorders like dementia.
  • Substance abuse: Certain types of chronic substance abuse are associated with specific types of mental illnesses. For instance, a chronic alcohol use disorder can be linked with the development of depression in some people, or the chronic abuse of stimulants can lead to problems with anxiety or paranoia in some people.
  • Environmental conditions that induce emotional stress: Experiencing stress, particularly extreme stress at an early age, is associated with many different types of mental illness. For instance, post-traumatic stress disorder is a form of mental illness that occurs following the experience of a very severe and significant life stressor. Abuse and/or neglect in childhood may increase the potential for the development of numerous types of mental illnesses.

How Do Cultural Factors Play a Link?

Perhaps one of the ways that culture influences the expression of mental illness can be seen in how different types of diagnoses vary across different cultures.

In some European countries like France, ADHD is diagnosed at a significantly lower rate than it is in the United States. Other cultures may view schizophrenia-type symptoms as a gift of spirituality or premonition.

Although some sources consider most forms of mental illnesses to be diseases, what constitutes a behavior as a mental illness is really defined by the specific culture within which the behavior occurs.

What Is a Risk Factor?

The term risk factor is an important one when discussing potential causes or sources of mental illness. A risk factor is a special condition or situation that increases the potential or probability that some type of disorder or illness will occur.

Risk factors are not causes. They simply stack the deck in favor of a particular outcome, but they do not guarantee that the outcome will occur.

In most of the research literature these days, risk factors for certain types of mental illness are more important to clinicians and researchers than attempting to explain specific root causes of mental illness. This is because most forms of mental illness are believed to be due to an interaction between inherent factors like genetics and the environment.

What Are Some Risk Factors for Mental Illness?

According to the American Psychological Association, there are certain risk factors that increase the potential to develop nearly any form of mental illness. These risk factors include:

  • Familial mental illness. Having a history of mental illness in your family (a blood relative) increases your likelihood to develop a mental illness. The closer the relative is to you, the greater the risk that you will develop some form of mental illness. For example, having a parent diagnosed with any type of mental illness significantly increases your risk for developing a mental illness, compared to having a distant cousin diagnosed with a mental illness.
  • Chronic medical conditions. Certain types of chronic medical conditions, such as diabetes, can increase the risk that you will develop some types of mental illnesses, such as depression.
  • Brain damage. Brain damage as a result of a traumatic brain injury or some other condition, like a stroke, increases the risk that you will develop many different forms of mental illness.
  • Stressful life situations or traumatic experiences. Many different types of stressors — including significant financial ruin or financial problems, the death of a loved one, divorce, and others — can increase the risk that you will develop some form of mental illness.
  • Neglect or abuse as a child. Being a victim of abuse or neglect as a child increases the risk that you will develop many different types of mental illness.
  • Drug or alcohol use or abuse. Using or abusing drugs or alcohol increases the risk that you will develop nearly every type of mental illness. Abuse increases the risk over standard use.
  • Having few friends or perceiving that you do not have sufficient social support can increase the risk of developing mental illness. Social support is recommended for those who have other risk factors for mental illness.
  • Low socioeconomic status. Living in poverty or near the poverty level is a risk factor for many types of mental illnesses.
  • A diagnosis of a mental illness. All of the mental illnesses listed in the DSM-5 are associated with the development of other co-occurring mental illnesses. For instance, people diagnosed with personality disorders are often at risk to develop depression, anxiety disorders, or substance use disorders (substance abuse or addiction).Many people diagnosed with one form of mental Illness are diagnosed with some other form of mental illness as well. If you have one type of mental health issue, be aware that this increases your risk to develop other forms of mental illness.

Complications of Mental Illness

Mental illness does not occur in a vacuum. When mental illness is left untreated, there are serious ramifications that can occur. The complications of mental illness can include but are not limited to:

  • Relationship difficulties. People who are diagnosed with mental illness often experience higher rates of divorce, family conflicts, and social isolation.
  • Decreased happiness. People who are diagnosed with mental illness typically report less life satisfaction than those who have no such diagnosis.
  • Higher mortality rates. People with chronic forms of mental illness often have higher rates of early mortality than people without these disorders.
  • Poor physical health. People with mental illness diagnoses often suffer from poorer physical health than the general population. They frequently have higher rates of heart disease, cancer, infectious disease, and other health conditions.
  • Financial problems. People with chronic forms of mental illness have higher rates of unemployment, poverty, bankruptcy, and other financial issues compared to the general population.
  • Homelessness. The percentage of homeless people who have a diagnosable form of mental illness is much higher than the percentage of homeless people who have no such diagnosis.
  • Higher likelihood to become involved in criminal activities or be the victim of a crime. People diagnosed with mental illness are more likely to commit crimes or be victims of crime than the general population.

A Complicated Picture

Some of the risk factors associated with developing mental illness are also some of the complications of mental illness. This is why it is very difficult to determine the causes of mental illness.

The relationships between these factors is very complex. In most cases, it is impossible to determine the exact underlying cause of any form of mental illness. Different people with the same diagnosis may have totally different risk factors and complications.

Thus, when mental illnesses are treated by clinicians, they are typically treated in a way that follows a general outline but directs the approach to the specific person. Treatment should be individualized to fit the needs and situation in question.

While there isn’t a single root cause of mental illness, various factors contribute to its development. Being aware of your personal risk factors can help you assess the likelihood that you may develop a mental health issue. This can help you to spot any issue early so you can get prompt treatment.

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