What Is a Chemical Imbalance?

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A chemical imbalance is too much or too little of any substance in the body that helps it function normally. While it can apply to an imbalance of any of these substances in any area of the body, the term is usually used to refer to imbalances in the brain.

Symptoms of a Chemical Imbalance in the Brain

Verywell / Michela Buttignol

What Is a Chemical Imbalance?

A chemical imbalance occurs when the substances that help the body function the way it should become out of balance. Either too much or too little of these substances can cause a chemical imbalance that affects the body’s ability to function normally.

These chemical imbalances are often linked to health conditions. For example, a hormonal imbalance occurs with polycystic ovary syndrome (PCOS), which in turn puts a person at risk for other conditions such as type 2 diabetes and infertility.

While too much or too little of these substances anywhere in the body is considered a chemical imbalance, the term “chemical imbalance” is usually associated with chemical imbalances in the brain and their potential effect on mental heath and related conditions.

Chemical Imbalances in the Brain

The chemicals in the brain that help facilitate communication between nerve cells are called neurotransmitters.

Some of the main neurotransmitters include:

  • Serotonin
  • Dopamine
  • Norepinephrine
  • Acetylcholine
  • GABA (gamma-aminobutyric acid)
  • Glutamate

These neurotransmitters help with many functions including:

  • Sleep
  • Appetite
  • Mood
  • Arousal
  • Behavior
  • Cognition
  • Pleasure
  • Early brain development
  • Memory
  • Learning
  • Stress response (“fight or flight”)

Dysfunction of these neurotransmitters has been linked to conditions such as:

  • Schizophrenia
  • Anxiety disorders
  • Depression
  • Bipolar disorder
  • Parkinson’s disease

While it is common to hear that depression and some other mental health conditions such as anxiety disorders are caused by a chemical imbalance, most mental health experts believe the causes of mental health conditions are more complex than the term implies.

The balance of chemicals in the brain is thought to be one influence on depression and anxiety disorders, along with a combination of factors such as:

  • Faulty mood regulation by the brain
  • Genetics
  • Environmental factors like stressful life events
  • Medications
  • Medical problems

Can Stress Cause a Chemical Imbalance?

In addition to affecting the balance of neurotransmitters, stress can affect chemical balances in multiple systems of the body including:

  • The nervous system
  • The digestive system
  • The endocrine (hormones) system
  • The cardiovascular system
  • The reproductive system

Is Depression Really Caused by a Chemical Imbalance?

The idea that depression is caused by a serotonin deficiency was popular in advertisements for antidepressant medications in the early 2000s, and many mental health professionals reflected this explanation to their patients.

There was little evidence to make this definitive conclusion. Rather, while there is evidence that shows antidepressants like selective serotonin reuptake inhibitors (SSRIs) can be effective in the treatment of depression, the exact reason for how this improvement happens isn’t known.

“Chemical imbalance” and “serotonin deficiency” were used as a metaphor for the more complex workings in the brain and factors involved with depression. This erroneously led many people to believe that treating depression with antidepressants was like treating hypothyroidism with thyroid medications or type 1 diabetes with insulin—a simple matter of replenishing low serotonin.

More recent advertising highlights that the medication affects neurotransmitters instead of correcting an imbalance. This reflects the complexity and nuance involved in treating depression and how treatments for mental health conditions are not one-size-fits-all.

It’s suggested that there is no “optimal” amount of neurotransmitters, so it would be difficult to define an imbalance. In addition, medications that are not SSRIs have also been shown to alleviate depression symptoms. This implies that depression is more than a simple chemical imbalance.

While brain chemicals play a part in depression, things like nerve cell connections, nerve cell growth, and the functioning of nerve circuits also contribute to depression.

Chemical Imbalance in the Brain Symptoms

Symptoms of a chemical imbalance in the brain are associated with several psychiatric diagnoses.


There are several forms of depression, each with its own unique list of symptoms. For a more complete list, it is best to research depression by type. Some of the more general symptoms of depression include:

  • Persistent sad, anxious, or “empty” mood
  • Feeling hopeless, negative, pessimistic
  • Irritability
  • Feelings of guilt, worthlessness, or helplessness
  • Loss of interest or pleasure in hobbies and activities (particularly ones you used to enjoy)
  • Decreased energy
  • Fatigue
  • Trouble concentrating, remembering, or making decisions
  • Sleep difficulties
  • Changes in weight or appetite
  • Thoughts of death or suicide, or suicide attempts
  • Unexplained physical symptoms, like aches, pains, headaches, and digestive problems

Anxiety Disorders

As with depression, there are several types of anxiety disorders which are best explored individually. Some general symptoms of anxiety disorders include:

  • Feeling panic, fear, and uneasiness
  • Uncontrollable, obsessive thoughts
  • Repeated thoughts or flashbacks of traumatic experiences
  • Sleep difficulties
  • Difficulty sitting still
  • Nightmares
  • Unexplained physical symptoms such as cold or sweaty hands, dry mouth, muscle tension, or numbness/tingling in hands or feet
  • Heart palpitations
  • Nausea
  • Shortness of breath


Schizophrenia has been strongly linked to a chemical imbalance in the brain. Symptoms of schizophrenia include:

  • Delusions: False beliefs that are not based on reality
  • Hallucinations: Experiencing sensations, particularly seeing or hearing things, that are not real
  • Disorganized speech and behavior
  • Lack of emotion/flat affect: Emotions don’t show outwardly
  • Paranoia: Feeling like someone or something is out to get you
  • Withdrawal from others

Causes of Chemical Imbalances in the Brain

Some things that may cause neurotransmitters to function improperly include:

  • Receptors may be oversensitive or insensitive to a specific neurotransmitter, causing them to respond too much or too little to the release of the neurotransmitter.
  • If the originating cell pumps out too little of a neurotransmitter, the message may be weakened.
  • An overly efficient reuptake that reabsorbs too much before the molecules have the chance to bind to the receptors on other neurons can also weaken the message.

It is important to note that these factors apply to neurotransmitter disruption and do not necessarily cause a mental health condition in and of themselves.

It is also hypothesized that the mitochondria may play a part in the function of neurotransmitters and their role in depression.


Unlike some other chemicals in the body, neurotransmitters can’t be accurately measured. It is not possible to determine that a person has a chemical imbalance in their brain.

The theory of chemical imbalance and its effect on mental health largely stems from the success in symptom reduction from medications when used to treat mental health conditions, but this link is far from clear-cut.

If conditions such as depression were conclusively caused by a chemical imbalance, antidepressants would work more quickly, as they impact levels of neurotransmitters relatively quickly. However, they typically take several weeks to produce a noticeable effect.

Instead of making a diagnosis of a chemical imbalance in the brain, diagnoses of specific mental health conditions are made.


Conditions that may be influenced by chemical imbalances in the brain might be treated with medications, psychotherapy, and lifestyle adjustments.


Antidepressants and other medications that affect brain chemistry are often prescribed to treat the conditions associated with a chemical imbalance. While these medications do help some people, they are not a cure-all.

Mental health disorders have multifaceted causes. While two people may share similar symptoms, they may have different pathologies and respond differently to treatment options.

Some medications prescribed to influence neurotransmitter function include:

Selective serotonin reuptake inhibitors (SSRIs)

SSRIs work by inhibiting the reuptake of serotonin. Examples include:

  • Celexa (citalopram)
  • Lexapro (escitalopram)
  • Luvox (fluvoxamine)
  • Paxil (paroxetine)
  • Prozac (fluoxetine)
  • Viibryd (vilazodone)
  • Zoloft (sertraline)

Serotonin and norepinephrine reuptake inhibitors (SNRIs)

SNRIs inhibit the reuptake of both norepinephrine and serotonin. Examples include:

  • Cymbalta (duloxetine)
  • Effexor (venlafaxine)
  • Fetzima (levomilnacipran)
  • Pristiq (desvenlafaxine)
  • Savella (milnacipran)

Tricyclic antidepressants (TCAs)

TCAs block the absorption of serotonin and norepinephrine, as well as having several other impacts on neurotransmitters. Examples include:

  • Anafranil (clomipramine)
  • Asendin (amoxapine)
  • Elavil (amitriptyline)
  • Norpramin (desipramine)
  • Pamelor (nortriptyline)
  • Sinequan (doxepin)
  • Surmontil (trimipramine)
  • Tofranil (imipramine)
  • Vivactil (protriptyline)

Monoamine oxidase inhibitors (MAOIs)

MAOIs inhibit the action of an enzyme called monoamine oxidase, making more neurotransmitters available for use in mood regulation. Examples include:

  • Emsam (selegiline)
  • Marplan (isocarboxazid)
  • Nardil (phenelzine)
  • Parnate (tranylcypromine)

Atypical antidepressants

These are newer antidepressants that don’t fit into the above categories. Examples include:

  • Oleptro (trazodone) and Trintellix (vortioxetine): Serotonin antagonist and reuptake inhibitors (SARIs)
  • Remeron (mirtazapine): Impacts receptors of the stress hormone epinephrine (adrenaline) as well as impacting serotonin in the brain
  • Wellbutrin (bupropion): Dopamine and norepinephrine reuptake inhibitor


Antipsychotics are used to manage psychosis (a loss of contact with reality). Examples of first-generation (“typical”) antipsychotic medications include:

  • Chlorpromazine
  • Haloperidol
  • Perphenazine
  • Fluphenazine

Examples of second-generation (“atypical”) antipsychotic medications include:

  • Risperidone
  • Olanzapine
  • Quetiapine
  • Ziprasidone
  • Aripiprazole
  • Paliperidone
  • Lurasidone

Non-Pharmaceutical Treatment

Psychotherapy treatments such as cognitive behavioral therapy (CBT) can be effective for many mental health conditions. These therapies may affect the function of neurotransmitters by changing neural pathways and associations.

For some people, exercise is helpful in symptom relief for depression and anxiety, in part by stimulating chemicals in the brain that make your body (and in turn your mind) feel better.

Non-pharmaceutical treatments may be enough on their own to help some people with depression or anxiety, but are often used in combination with medication.


A chemical imbalance can happen anywhere in the body, but usually refers to the association between neurotransmitter function and mental health. It isn’t possible to determine if you have a chemical imbalance in the brain, but there are many symptoms of mental health conditions such as depression and anxiety that are associated with what is colloquially known as a chemical imbalance.

A Word From Verywell

If you are experiencing symptoms of a mental health condition, or notice changes in your mood or mental functioning, see your healthcare professional to discuss a possible diagnosis and make a treatment plan.

Frequently Asked Questions

  • How do I know if I have a chemical imbalance?

    There is no reliable test for a chemical imbalance in the brain. Symptoms of mental health conditions such as anxiety or depression may indicate some problems with the way the brain—including the chemicals in the brain—is functioning.

    If you are experiencing symptoms of a mental health condition associated with chemical imbalance, see your healthcare professional to explore a diagnosis and treatment options.

  • What does it mean to have a chemical imbalance?

    The term “chemical imbalance” is somewhat of a catch-all phrase used to discuss dysfunction in the brain associated with some mental health conditions.

    The chemicals in the brain that help facilitate communication between nerve cells are called neurotransmitters. A disruption in their proper functioning can affect mood and other bodily processes.

  • What causes a chemical imbalance in the brain?

    Any disruption in the complicated process of nerve cell communication has the potential to affect the production and/or function of neurotransmitters and by extension a person’s mental health.

  • How do you fix a chemical imbalance in the brain?

    Chemicals in the brain can’t be accurately measured, and these chemicals' optimal level is unknown (if there is one at all). In that sense, a chemical imbalance in the brain can’t be “fixed.”

    Brain chemistry can be influenced by some medications such as antidepressants and antipsychotics. These have been shown to help improve the symptoms of mental health conditions associated with a chemical imbalance in the brain.

    Experts do not know exactly how these medications work to create this effect, but it is believed to involve more than simply replenishing brain chemicals.

15 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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Additional Reading

By Heather Jones
Heather M. Jones is a freelance writer with a strong focus on health, parenting, disability, and feminism.