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Can something trigger a mental illness?

Mental illnesses are complex conditions that affect a person’s mood, thoughts, and behavior. There are many different types of mental illnesses, including depression, anxiety disorders, schizophrenia, eating disorders, and addictive behaviors. While the exact causes of mental illnesses are not fully understood, researchers believe there is no single cause. Rather, mental illnesses are thought to result from a combination of genetic, biological, environmental, and psychological factors.

One question that often arises is whether something specific can trigger the onset or worsening of a mental illness in a person who is predisposed. This article will examine the evidence around potential mental illness triggers and discuss what is known and still unknown in this area of research.

Stress as a Trigger

Stress is one of the most commonly discussed potential triggers for mental illness. Stress refers to the body’s response to demanding situations and events. While a certain amount of stress is normal and even beneficial at times, chronic, unmanaged stress can take a toll on mental health.

Research indicates that chronic stress may play a role in the development of some mental illnesses, especially depression and anxiety disorders:

  • People with depression often report experiencing major stressful life events like divorce, job loss, or the death of a loved one prior to the onset of their depression.
  • Chronic stress levels are linked with greater rumination and pessimism, thought patterns associated with depression.
  • Studies show childhood trauma and adverse experiences, significant sources of stress, increase the risk for depression later in life.
  • Stressful events are commonly reported to worsen symptoms for those already diagnosed with depression and anxiety disorders.
  • Chronic stress leads to elevated levels of cortisol and other stress hormones that can impact brain chemistry linked to mood regulation.

So while stress itself does not directly cause mental illness in someone with no biological vulnerability, it does appear capable of triggering or intensifying illnesses like depression and anxiety in those predisposed. This may occur due to the effects of sustained stress hormone elevations on the brain or because chronic stress leads to negative thought patterns than maintain these disorders.

Trauma as a Trigger

Trauma, referring to any disturbing or distressing event, is another commonly cited trigger for mental illnesses like post-traumatic stress disorder (PTSD), depression, and anxiety disorders. Research suggests:

  • Individuals who experience traumatic events like abuse, violence, disasters, accidents and more are at higher risk of developing PTSD.
  • Childhood trauma from events like abuse or neglect is linked to greater likelihood of depression later in life.
  • Trauma sufferers often develop negative thought patterns like rumination, catastrophizing, and hopelessness that can worsen depression and anxiety symptoms.
  • The brain’s response to trauma may impact regions like the hippocampus and amygdala that regulate emotions and memory.

So substantial evidence indicates traumatic experiences can alter brain functioning and psychology in ways that trigger PTSD in some and worsen conditions like depression and anxiety for others. Those with an underlying biological vulnerability may be most impacted. The changes to brain connectivity and chemistry that trauma can cause appear capable of unveiling or intensifying latent mental illnesses.

Substance Use as a Trigger

Substance use, involving drugs, alcohol, medications, and toxins, is another potential mental illness trigger. Substance use impacts brain chemistry and may unveil or intensify psychiatric conditions, especially in those with predisposing factors:

  • Heavy alcohol use can deplete neurotransmitters like serotonin linked to mood regulation and is associated with increased depression risk.
  • Cannabis use may worsen outcomes for those vulnerable to schizophrenia and psychosis.
  • Cocaine and amphetamines can trigger manic episodes in those predisposed to bipolar disorder.
  • Sedative withdrawal can cause potentially life-threatening depression, anxiety, and psychosis.
  • Prescription medications like steroids may also trigger psychiatric symptoms in some.

In those with a biological vulnerability to mental illness, substance use and withdrawal often serve as stressors that can worsen or trigger depression, anxiety, psychosis, and other psychiatric disease. However, substances themselves do not directly cause illness in otherwise healthy individuals. Those with mental illnesses often use substances to self-medicate, complicating the relationship.

Infections as Potential Triggers

Some research indicates that infections from bacteria, viruses, and parasites may act as triggers of mental illness in those with underlying risk factors:

  • Childhood infections are linked to greater risk of developing schizophrenia and psychosis later in life.
  • Inactive toxoplasma infection may be linked to schizophrenia and bipolar disorder.
  • Symptoms of depression and anxiety can occur in responding to infections.
  • Infections may impact neurotransmitters like dopamine and glutamate linked to psychiatric disease.
  • Brain inflammation from infection may alter neurochemistry.

While more research is needed, some scientists hypothesize that the immune response to certain childhood infections could alter neurodevelopment or brain chemistry in a way that predisposes people to later mental illness. However, infections themselves do not directly cause psychiatric disease de novo. More likely, they serve as environmental triggers in those with genetic vulnerabilities.

Inflammation as a Potential Trigger

Inflammation refers to the body’s immune and healing response to harm, injury, and pathogens. Acute inflammation is beneficial, but chronic inflammation is linked to disease. Some evidence associates chronic inflammation with mental illness:

  • Those with autoimmune disorders like lupus have higher rates of psychiatric disorders.
  • Markers of inflammation like C-reactive protein are elevated in those with depression.
  • Cytokines and other inflammatory chemicals may impact neurotransmitters.
  • Brain inflammation may play a role in the onset of psychotic disorders.

Researchers hypothesize chronic inflammation may impact neurotransmitter function and neurocircuits in ways that could worsen or trigger mental illness activity. Things that drive prolonged inflammation like obesity, poor diet, stress, and infections may indirectly impact mental health in this way. However, more research is needed to confirm if inflammation is a true trigger.

Nutrient Deficiencies as Potential Triggers

Nutrient deficiencies, especially in critical amino acids, vitamins, minerals, and fatty acids, are sometimes considered possible triggers for mental illness:

  • Deficiencies in amino acids like tryptophan may reduce serotonin levels.
  • Vitamin D deficiency is associated with increased risk for schizophrenia and depression.
  • Folate deficiency is linked to worse outcomes for schizophrenia and depression.
  • Omega-3 fatty acids play structural roles in brain cell membranes.

Since some nutrients play important roles in neurotransmitter synthesis and brain cell structure, deficiencies could theoretically contribute to psychiatric disease onset and progression. However, direct causative links are lacking, and confounding factors like poor diet quality often coincide with deficiencies. For those predisposed, correcting deficiencies may potentially help improve outcomes.

Genetic Factors vs. Triggers

While the factors discussed may contribute to the likelihood or severity of mental illness, it is important to note they are not direct causal factors by themselves. Mental illnesses also have a strong inherited genetic component that likely provides the foundational vulnerability:

  • Mental illness risk is higher among identical twins of affected individuals.
  • Specific gene variants associated with mental illnesses have been identified.
  • Certain psychiatric disorders like schizophrenia run in families.

Genetics account for an estimated 30-40% of risk for disorders like depression and schizophrenia. Without this underlying biological vulnerability, potential triggers are unlikely to directly cause full-blown mental illness in someone. However, genetics alone are not determinative either. Complex gene-environment interactions are likely at play.

A Biopsychosocial Model

Current thinking supports a biopsychosocial model of mental illness development, progression, and triggering. In this model:

  • Biological factors like genetics, brain chemistry, hormones, and nutrients provide a foundational level of vulnerability.
  • Psychological factors like traumatic experiences, thought patterns, and coping mechanisms influence outcomes.
  • Social/environmental factors like stressors, trauma, infections, inflammation, and substance use can worsen and trigger illnesses.

Triggers alone are unlikely to cause disease without an underlying biological vulnerability. However, they may interact with genetic factors to initiate or intensify illness activity. Ongoing interplay between biological, psychological, and social factors then determine disease progression and severity.

The Importance of Managing Vulnerabilities

Since various factors may trigger worsening symptoms, managing vulnerabilities is important for those with mental illnesses like depression and anxiety:

  • Reducing chronic stress through self-care, social support, and counseling.
  • Seeking treatment after trauma and avoiding reinjury.
  • Carefully managing substance use with professional help.
  • Engaging in psychotherapy to change thought patterns.
  • Optimizing diet, exercise, sleep, and medical care to reduce inflammation.
  • Taking medications and supplements under medical supervision.

While symptomatic worsening can be discouraging, identifying potential triggers like stress, trauma, or inflammation can provide opportunities for self-management and growth. Working closely with medical and mental health professionals is key.


Mental illnesses develop from a complex combination of genetic vulnerabilities and environmental interactions over time. While no single factor directly causes mental illness by itself, variables like chronic stress, trauma, inflammation, and others may trigger worsening symptoms or disease progression in those with biological susceptibility. Ongoing research aims to better elucidate these gene-environment interactions. However, at present a biopsychosocial model with multiple contributing factors best explains the evidence. Moving forward, holistic management of all potential factors is needed.