Stress vulnerability model in occupational therapy

The Stress-Vulnerability Model
of Co-occurring Disorders

  • What causes psychiatric disorders?
  • Why do some people develop a psychiatric disorder but others don’t?
  • What affects the course of the disorder?

These are common questions raised by people with co-occurring disorders and their family members. The stress-vulnerability model provides answers to these questions. This model can help in understanding the causes of psychiatric disorders, how psychiatric disorders and addiction can influence each other, and how co-occurring disorders can be managed and treated together.

Handout available

This information is also available as a PDF, which is included in the Hazelden Co-occurring Disorders Program.

Download the Stress-Vulnerability Model handout

As the name suggests, two main factors are involved. “Vulnerability” refers to our basic susceptibility to mental health disorders. This is determined by our genetic makeup and our early life experiences. It is affected by our use of medications and our likelihood of using alcohol or drugs. “Stress” refers to the challenges faced in our lives. It is affected by our coping skills, social support, and involvement in meaningful activities.

Biological Vulnerability

If we are vulnerable to something, it means we’re more likely to be affected by it. For example, some people might be biologically vulnerable to certain physical illnesses-such as heart disease or asthma. Maybe the disease runs in the family, or maybe something in our early life “set us up” for it.

Some people are biologically vulnerable to certain psychiatric disorders: bipolar disorder, major depression, schizophrenia, or anxiety disorders (panic, post-traumatic stress), for example. This vulnerability is determined early in life by a combination of factors, including genetics, prenatal nutrition and stress, birth complications, and early experiences in childhood (such as abuse or the loss of a parent). This is why some families are more likely to have members with a particular psychiatric disorder. Although vulnerability to psychiatric disorders is primarily biological in nature, people can take steps to reduce their vulnerability, including taking medication and not using alcohol or drugs. It’s also worth noting that the greater a person’s vulnerability to a particular disorder, the earlier it is likely to develop, and the more severe it may become.

Similarly, some people also have a biological vulnerability to developing an addiction: they are more likely to develop alcohol or drug abuse or dependence. This is why addiction, similar to psychiatric disorders, sometimes “runs in families.”

What Are the Elements of the Stress-Vulnerability Model?

These two main areas — biological vulnerability and stress — are influenced by several other factors that people have some control over. These factors include

  • alcohol and drug use 

  • medication use 

  • coping skills 

  • social support 

  • meaningful activities

This means that by addressing these factors, people can reduce symptoms and relapses and improve the course of their co-occurring disorders.

Alcohol and Drug Use

Using alcohol or drugs can increase a person’s pre-existing biological vulnerability to a psychiatric disorder. Thus, substance use can trigger a psychiatric disorder and lead to more severe symptoms and other impairments. Because most people with co-occurring mental and substance use disorders have a biological vulnerability to psychiatric disorders, they tend to be highly sensitive to even small amounts of alcohol and drugs.


Stress in the environment can worsen biological vulnerability, worsen symptoms, and cause relapses. Stress is anything that challenges a person, requiring some kind of adaptation. Serious stressful events include losing a loved one, getting fired from a job, being a victim of crime, or having conflicts with close people.

Stress is often associated with negative events, but positive events and experiences may be stressful as well. For example, performing well in school, getting a new job, starting a new relationship, having a baby, or being a parent all involve some degree of stress.

It is also possible for stress to be caused by not having enough to do. When people with co-occurring disorders have nothing purposeful or interesting to do, they tend to have worse symptoms and are more prone to using substances. So a lack of meaningful involvement in life-in areas such as work or parenting, for example-can be another source of stress.

Coping Skills

Developing coping strategies can help with handling stress and reducing its negative effects on vulnerability. Examples of coping skills include

  • relaxation skills for dealing with stress and tension 

  • social skills for connecting with people, dealing with conflict, and getting support 

  • coping skills for managing persistent symptoms such as depression, anxiety, and sleeping problems

Stress is a normal part of life. Effective coping enables people to be engaged in interesting, rewarding activities that may involve stress, such as working or being a parent. Coping efforts can make it possible for someone with co-occurring disorders to live a normal life without suffering the negative effects of stress.

Involvement in Meaningful Activities

Having something meaningful to do with one’s time gives one a sense of purpose, and reduces the stress of having nothing to do. Meaningful activities can include:

  • work 

  •  school 

  •  parenting or other caregiving responsibilities 

  •  homemaking

Social Support

Another way to reduce the negative effects of stress on vulnerability is through social support, which comes from having close and meaningful relationships with other people. Supportive people can help in a variety of ways, such as

  • helping people solve challenging Problems 

  • supporting people in using coping strategies to deal with symptoms and substance-use urges 

  • being open and willing to discussing and resolving personal disagreements, misunderstandings, and areas of conflict that could otherwise lead to stress 

  • letting people know that they are important and cared about 

  • supporting the person in pursuing personally meaningful goals

People who have good social support are less vulnerable to the effects of stress on their psychiatric disorder. Therefore, having strong social support enables people with co-occurring disorders to handle stress more effectively, and live a normal life.

Treatment Implications of the Stress-Vulnerability Model

Based on an understanding of the stress-vulnerability model, there are many ways to help people manage their psychiatric illness and co-occurring substance use disorder. In the broadest terms, the severity and course of a co-occurring mental health disorder can be improved by reducing biological vulnerability and increasing resiliency against stress.

Reducing Biological Vulnerability

Biological vulnerability can be reduced in two primary ways: taking medication and avoiding alcohol or drug use. Medication can be a powerful way of reducing biological vulnerability by helping to correct the imbalances in neurotransmitters (chemicals in the brain responsible for feelings, thinking, and behavior) believed to cause psychiatric disorders. By taking medication, the symptoms of a psychiatric disorder can be lowered and the chances of having a relapse can also be reduced.

Avoiding alcohol and drug use can reduce biological vulnerability in two ways. First, because substances affect the brain, using alcohol or drugs can directly worsen those vulnerable parts of the brain associated with psychiatric disorders. Second, using substances can interfere with the corrective effects of medication on vulnerability. This means that somebody who is using alcohol or drugs will not get the full benefit of any prescribed medications for his or her disorder, leading to worse symptoms and a greater chance of relapses.

Increasing Resiliency against Stress

It is impossible for anyone to live a life that is free of stress. However, there are many ways people can learn how to deal with stress more effectively, and to protect themselves from the effects of stress on worsening symptoms and causing relapses, including

  • developing effective coping skills for managing stress and persistent symptoms 

  • getting involved in meaningful activities that structure one’s time and reduce the stress of having nothing to do 

  • building socially supportive relationships that help one manage the mental health disorder and maintain sobriety


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Diathesis–Stress Model

By Oliver Sussman, published March 14, 2022

What is Diathesis?

The term “diathesis” comes from the Greek word for disposition (“diathesis”). In the context of the diathesis-stress model, this disposition is a factor that makes it more likely that an individual will develop a disorder following a stressful life event.

A diathesis can take the form of a biological factor, like abnormal variations in one or more genes. But other sorts of factors, even if not genetically hard-wired, can also be considered diatheses so long as they form early on and are stable across a person’s life.

For example, traumatic early life experiences, such as the loss of a parent, can act as longstanding predispositions to psychological disorder. In addition, personality traits like high neuroticism are sometimes also referred to as diatheses.

Finally, diatheses can be situational factors — like living in a low income household, or having a parent with mental illness (Theodore, 2020).

Some of these factors might matter more for some psychological disorders compared to others (for example, a particular genetic variation might increase one’s risk of developing depression, but not schizophrenia).

It’s important to note that not all diatheses are created equal. For example, some genetic variations only slightly increase an individual’s risk of a mental disorder, while others increase one’s risk substantially. As a result, in the diathesis-stress model, different diatheses give rise to different responses to stress.

To conceptualize this, consider the “cup analogy.” Imagine several cups, each filled with a different amount of marbles; when water is poured into those cups, the cups with more marbles will overflow more easily.

Diatheses are like marbles, and stress is like water: the greater the diathesis, the less stress needed to cause “overflow” (i.e., give rise to mental illness) (Theodore, 2020).

Diathesis-Stress Model

 The diathesis-stress model is a concept in psychiatry and psychopathology which offers a theory of how psychological disorders come about.

It intervenes in the debate about “nature vs. nurture” in psychopathology — whether disorders are predominantly caused by innate biological factors (“nature”) or by social and situational factors (“nurture”) — by providing an account of how both might coincide in giving rise to a disorder.

According to the diathesis-stress model, the emergence of a psychological disorder requires first the existence of a diathesis, or an innate predisposition to that disorder in an individual; and second, a stress, or a set of challenging life circumstances which then trigger the development of the disorder.

Furthermore, individuals with greater innate predispositions to a disorder may require less stress for that disorder to be triggered, and vice versa.

In this way, the diathesis-stress model explains how psychological disorders might be related to both nature and nurture, and how those two components might interact with one another (Broerman, 2017).

The diathesis-stress model is a modern development of a longstanding debate about the causes of mental illness. This debate began as early as ancient Greece and Rome, when theories included imbalances in bodily fluids and interactions with the devil.

Later, this evolved into the “nature vs. nurture” debate. By the late 20th century, it became clear that nature interacted with nurture to produce disorder, and the diathesis-stress model came to the forefront (Theodore, 2020).

The model has been useful in explaining why some individuals with biological dispositions to mental illness do not develop a disorder, and why some individuals living through stressful life circumstances nonetheless remain psychologically healthy.

It has also opened the door to research into protective factors: positive elements which counteract the effects of diathesis and stress to prevent the onset of a disorder. Finally, it has proven particularly useful in the context of specific disorders, such as schizophrenia and depression.

Diathesis and Stress Interactions

According to the diathesis-stress model, diatheses interact with stress to bring about mental illness. In this context, “stress” is an umbrella term which encompasses any life event that disrupts an individual’s psychological equilibrium — their normal, healthy regulation of thoughts and emotions.

In the diathesis-stress model, these challenging life events are thought to interact with individuals’ innate dispositions to bring psychological disorders to the surface.

Stress comes in many different forms. It may be a single, traumatic event, like the death of a close relative or friend. But stress can also be an ongoing, sustained challenge in one’s life, like a chronic illness or an abusive relationship.

It can even be more mundane, the sorts of things we usually mean when we talk about “stress” — like anxiety from work or school (Theodore, 2020). In any case, these events or situations can have a profound impact on individual psychology and interact with diatheses to foment mental illness.

The role of stress in the diathesis-stress model is nuanced. For one, some life circumstances may constitute both a diathesis and a stress. For instance, a child with a parent who suffers from mental illness may both be genetically predisposed to that illness, and may also undergo stress as a result of her parent’s condition (Theodore, 2020).

Second, the timing of stress within an individual’s lifespan may be important; certain disorders are thought to have “windows of vulnerability” during which they are more likely to be brought about by stressful life events (Lokuge, 2011)

Moreover, stress may be counteracted by positive life circumstances, called protective factors, which decrease the likelihood that a disorder will emerge in response to stress.

Finally, different stresses are thought to play different roles across mental disorders — in other words, a particular form of stressful life event may play an especially pronounced role in depression, or schizophrenia, etc. These last two points will be explored in the sections below. 

Protective Factors

Just as there can be negative elements in one’s life that make the onset of a psychological disorder more likely, there can also be positive elements which make the onset of a disorder less likely. These positive elements are called protective factors.

Protective factors help explain why some people who have both significant diatheses and stresses nonetheless remain psychologically healthy — in these cases, protective factors prevent a disorder from coming to the surface (Theodore, 2020).

Protective factors can be conditions, meaning beneficial life circumstances that protect against mental illness. They can also be attributes: traits or behaviors of an individual that make them more resilient against psychological disorders (“Protective Factors”).

Conditions which act as protective factors include strong parental and social support and assistance from psychotherapists or counselors. Attributes which act as protective factors include social and emotional competence, and the use of healthy coping strategies and stress management techniques (Theodore, 2020).

By itself, the diathesis-stress model does not necessarily include protective factors in its assessment of the causes of psychological disorder.

As a result, the model has been updated in recent years to accommodate protective factors. This updated model is sometimes called the stress-vulnerability-protective factors model (Theodore, 2020).


The diathesis-stress model has proven useful in illuminating the causes of specific psychological disorders. One area where the model has had considerable success is schizophrenia, a disease with both genetic and environmental causes.

While schizophrenia has a strong genetic component, some individuals with genetic susceptibilities to the disorder nonetheless remain healthy.

As a result, the view currently held by many psychiatrists is that schizophrenia requires a genetic predisposition in combination with stress later on in life, which then triggers the emergence of the disorder.

Some researchers have also put forth a neural diathesis-stress model of schizophrenia, in which they attempt to explain how brain changes resulting from diatheses and stresses give rise to the disorder (Jones and Fernyhough, 2007).

Thus, the diathesis-stress model does well to explain the origins of schizophrenia, and has even been supported by evidence from neuroscience.

The diathesis-stress model has also been used to explain the origins of depression. Similarly to schizophrenia, genetic risk factors for depression have been identified, but not all people with those risk factors go on to develop the disorder.

According to the diathesis-stress model of depression, stressful life events interact with genetic predispositions to bring about depressive symptoms.

This model of depression has been validated by research — a study found there to be an interaction effect between genetic risk factors for depression and scores on an inventory of stressful life events in predicting depressive symptoms (Colodro-Conde et al., 2018).

The model has also proven useful in explaining suicidal behavior. Early models of suicidal behavior tended to focus exclusively on stress, which failed to account for why some individuals exposed to extreme stress nonetheless refrain from engaging in suicidal behavior.

Since suicidal behavior likely also relies on an interaction between genetic and early childhood dispositions with stress later in life, researchers have suggested that efforts to treat and prevent suicidal behavior should utilize a diathesis-stress model (van Heeringen, 2012).

Different psychological disorders have different causes. Some may rely more strongly on hard-wired predispositions, while others may be more responsive to stressful events later in life.

Nevertheless, the diathesis-stress model has been shown to have widespread applicability across many areas of psychiatry. It offers a powerful explanation of how nature and nurture might come together to give rise to mental illness, a much-needed advancement over earlier theories which took one or the other to be completely determinative.

About the Author

Oliver Sussman is an undergraduate at Harvard University studying neuroscience within the interdisciplinary Mind, Brain, and Behavior program. He is currently conducting research in cognitive neuropsychology on the organization of knowledge about actions and objects in the brain. After graduation, Oliver hopes to pursue a research fellowship or a Master’s program in cognitive science.

How to reference this article:

Sussman, O. (2022, March 14). Diathesis–Stress Model. Simply Psychology.

APA Style References

Broerman, R. (2017). Diathesis-Stress Model. In V. Zeigler-Hill & T. K. Shackelford (Eds.), Encyclopedia of Personality and Individual Differences (pp. 1–3). Springer International Publishing.

Colodro-Conde, L., Couvy-Duchesne, B., Zhu, G., Coventry, W. L., Byrne, E. M., Gordon, S., Wright, M. J., Montgomery, G. W., Madden, P. a. F., Major Depressive Disorder Working Group of the Psychiatric Genomics Consortium, Ripke, S., Eaves, L. J., Heath, A. C., Wray, N. R., Medland, S. E., & Martin, N. G. (2018). A direct test of the diathesis-stress model for depression. Molecular Psychiatry, 23(7), 1590–1596.

DIATHESIS | Meaning & Definition for UK English | (n.d.). Lexico Dictionaries | English. Retrieved February 23, 2022, from

Jones, S. R., & Fernyhough, C. (2007). A new look at the neural diathesis–stress model of schizophrenia: The primacy of social-evaluative and uncontrollable situations. Schizophrenia Bulletin, 33(5), 1171–1177.

Lokuge, S., Frey, B. N., Foster, J. A., Soares, C. N., & Steiner, M. (2011). Depression in women: Windows of vulnerability and new insights into the link between estrogen and serotonin. The Journal of Clinical Psychiatry, 72(11), e1563-1569.

Protective Factors to Promote Well-Being and Prevent Child Abuse & Neglect—Child Welfare Information Gateway. (n.d.). Retrieved February 23, 2022, from

Theodore. (2020, April). Diathesis-Stress Model (Definition + Examples). Retrieved from

van Heeringen, K. (2012). Stress–Diathesis Model of Suicidal Behavior. In Y. Dwivedi (Ed.), The Neurobiological Basis of Suicide. CRC Press/Taylor & Francis.

Walker, E. F., & Diforio, D. (1997). Schizophrenia: a neural diathesis-stress model. Psychological review, 104(4), 667.



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