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What are some common terms associated with depression?

The following glossary contains medical definitions to help you understand terms related to the treatment of depression.

Adverse reactions

Any undesired actions or effects of a drug or treatment. Adverse reactions are also known as side effects. They are recorded as the percentage of patients who experience them; for example, if 10 people out of 100 in a clinical trial take a medicine and develop a headache, then 10% of the study participants experienced this adverse reaction.


Medications that treat depression. There are several different types of antidepressants, such as selective serotonin reuptake inhibitors, serotonin and norepinephrine reuptake inhibitors, tricyclic antidepressants, and monoamine oxidase inhibitors. They vary in how they work, in their side effects, and how they may interact with other medications.

Clinical trial

A research study designed to answer specific questions about new therapies or new ways of using known treatments. Clinical trials are used to determine whether new drugs or treatments are both safe and effective.


A situation in which a drug, procedure, or treatment should not be used because it may be harmful to the patient.

Controlled study

A trial in which a test treatment is compared with a treatment that has known effects. While one treatment group receives the medication being studied, another group, called the control group, receives either no treatment, standard treatment (which may be another medicine or another approach to care), or placebo (sugar pill) in order to compare the effects of different treatments.

Diagnostic and Statistical Manual of Mental Disorders (DSM)

The standard classification reference for mental disorders used by mental health professionals in the United States.

Food and Drug Administration (FDA)

The U.S. Department of Health and Human Services agency responsible for ensuring the safety and effectiveness of all drugs, biologics, vaccines, and medical devices.

Major depressive disorder (MDD)

A serious medical condition that is characterized by a combination of symptoms, including persistent sad, anxious, or "empty" moods; feelings of hopelessness, guilt, or worthlessness; helplessness and loss of interest or pleasure in activities that were once enjoyed. Symptoms of depression interfere with normal functioning and are not associated with other psychiatric conditions, including mixed, manic, or hypomanic episodes.

Major depressive episode

A person with depression has at least 5 of the following symptoms:

  • Depressed mood
  • Loss of interest or pleasure
  • Feelings of worthlessness or guilt
  • Agitation or restlessness
  • Fatigue or loss of energy
  • Trouble thinking, making decisions, or concentrating
  • Disturbed sleep, such as insomnia
  • Changes in appetite or weight
  • Thoughts of death or suicide or suicide attempts

At least one of the symptoms must be depressed mood or loss of interest or pleasure. These symptoms must be present during the same 2-week period and represent a change from previous functioning.

Montgomery-Asberg Depression Rating Scale (MADRS)

A rating scale used by researchers to assess the severity of depression among diagnosed patients. It is designed to be sensitive to change resulting from treatment.


A chemical in the brain that transmits nerve impulses from one neuron to an adjacent neuron at a place called a synapse.


A neurotransmitter and a hormone that aids in the regulation of cognition, motivation, and intellect.


A biologically inactive substance administered to some participants in a clinical trial for the purpose of comparing no treatment to active treatment. In a blinded trial, patients do not know whether they are receiving a placebo or the drug being tested.


A physician who specializes in the diagnosis and treatment of mental illnesses.


The medical specialty concerned with the diagnosis and treatment of mental illnesses.


A person trained in the study of the mind and behavior in relation to different areas of human activity, including the family, education, and employment and also trained in the treatment of mental health problems.


A professionally trained and licensed person who uses a variety of techniques to improve the mental health and coping skills of their patients. Psychotherapists come from diverse backgrounds and include psychologists, counselors, social workers, and psychiatrists.


Treatment of emotional, behavioral, personality, and psychiatric disorders in the context of an established therapeutic relationship between a psychotherapist and client/group. Most forms of psychotherapy use verbal communication; interpersonal and cognitive-behavioral therapies are among the most common.

Selective serotonin reuptake inhibitor (SSRI)

A class of antidepressants used to treat major depressive disorder. SSRIs are thought to work by inhibiting the reuptake of serotonin, an action which allows more serotonin to be available to be taken up by other nerves.

Serotonin and norepinephrine reuptake inhibitor (SNRI)

A class of antidepressants used to treat major depressive disorder. SNRIs are thought to work by inhibiting the reuptake of serotonin and norepinephrine.


A neurotransmitter that aids in the regulation of mood, appetite, sleep, muscle contraction, and some brain functions, including memory and learning.

Sheehan Disability Scale (SDS)

A self-rated scale, designed to measure the extent to which a patient’s functioning is impaired by depressive symptoms in three major categories: work/school life, social life, and family/home life.


FETZIMA (levomilnacipran) extended-release capsules is a serotonin and norepinephrine reuptake inhibitor (SNRI) indicated for the treatment of Major Depressive Disorder (MDD) in adults.

FETZIMA is not approved for the management of fibromyalgia, and its efficacy and safety have not been established for that use.


What is the most important information I should know about depression, antidepressant medicines, other serious mental illnesses, suicidal thoughts or actions and serotonin syndrome?

FETZIMA and other antidepressant medicines may cause serious side effects.

What is the most important information I should know about depression, antidepressant medicines, other serious mental illnesses, suicidal thoughts or actions and serotonin syndrome?

FETZIMA and other antidepressant medicines may cause serious side effects.


Antidepressants increased the risk of suicidal thoughts and behavior in children, teenagers, and young adults.
In patients of all ages who are started on antidepressant therapy, watch closely for worsening depression and for suicidal thoughts and behaviors. Families and caregivers of patients on antidepressants should talk with the patient's doctor if depression becomes worse.
FETZIMA is not approved for use in patients under 18.
Call your healthcare provider right away if you have any of these symptoms, especially if they are new, worse, or worry you:
  • Attempts to commit suicide; acting on dangerous impulses; acting aggressive; being angry or violent; thoughts about suicide or dying; new or worsening depression or anxiety; feeling very agitated or restless; panic attacks; trouble sleeping; new or worsening irritability; an extreme increase in activity or talking (mania); or other unusual changes in behavior or mood

Serotonin Syndrome: A rare, but potentially life-threatening condition can happen when medicines such as FETZIMA are taken with certain other medicines. Serotonin syndrome can cause serious changes in how your brain, muscles, heart and blood vessels, and digestive system work. Symptoms of serotonin syndrome may include: agitation; hallucinations; coma or other changes in mental status; coordination problems or muscle twitching; fast heartbeat; high or low blood pressure; sweating or fever; nausea; vomiting or diarrhea; or muscle stiffness or tightness

Who should not take FETZIMA?
DO NOT take FETZIMA if you:
  • Are allergic to levomilnacipran, milnacipran HCl, or any of the ingredients in FETZIMA
  • Have taken any drugs known as monoamine oxidase inhibitors (MAOIs) within the last 14 days, including the antibiotic linezolid or intravenous methylene blue
What should I tell my healthcare provider before taking FETZIMA?
Tell your healthcare provider if you:
  • Have high blood pressure or tend to have a fast heart rate
  • Have heart or kidney problems
  • Have or had bleeding problems. FETZIMA may increase your risk of bleeding or bruising
  • Have or had trouble urinating
  • Have or had mania, bipolar disorder (manic depression), seizures or convulsions
  • Have low salt (sodium) levels in your blood
  • Drink alcohol
  • Are pregnant, nursing, or are planning to become pregnant or to breastfeed
Tell your healthcare provider about all prescription, over-the-counter medicines, vitamins and herbal supplements you are taking or plan to take, especially:
  • Triptans used to treat migraine headaches; medicines used to treat mood, anxiety, psychotic or thought disorders, including tricyclics, lithium, SSRIs, SNRIs, buspirone, amphetamines, or antipsychotics; tramadol, fentanyl; over-the-counter supplements such as tryptophan or St. John's Wort, to avoid a potentially life-threatening condition
  • Aspirin, non-steroidal anti-inflammatory drug (NSAID) pain relievers, or blood thinners (eg, warfarin, Coumadin®, or Jantoven®) because they may increase the risk of bleeding
  • Diuretics (water pills)
What should I avoid while taking FETZIMA?
  • Until you know how FETZIMA affects you, you should not drive, operate heavy machinery, or engage in other dangerous activities
  • Avoid drinking alcohol while taking FETZIMA
What are the possible side effects of FETZIMA?
FETZIMA may cause serious side effects, including:
  • High blood pressure and/or increased heart rate
  • Abnormal bleeding: FETZIMA and other antidepressant medicines may increase your risk of bleeding or bruising, especially if you take blood thinners (eg, warfarin, Coumadin, or Jantoven), a non-steroidal anti-inflammatory drug (NSAID), or aspirin
  • Visual problems: Eye pain; changes in vision; swelling or redness in or around the eye. Only some people are at risk for these problems. You may want to undergo an eye examination to see if you are at risk and receive preventative treatment if you are
  • Trouble urinating
  • Hypomania (manic episodes): Greatly increased energy; severe trouble sleeping; racing thoughts; reckless behavior; unusually grand ideas; excessive happiness or irritability, or talking more or faster than usual
  • Seizures or convulsions
  • Discontinuation symptoms: Do not stop FETZIMA without first talking to your healthcare provider. Stopping FETZIMA suddenly may cause serious symptoms, including: anxiety; irritability; high or low mood; feeling restless or sleepy; headache; sweating; nausea; dizziness; electric shock-like sensations; tremor; or confusion
  • Low salt (sodium) levels in the blood: Symptoms may include headache, difficulty concentrating, memory changes, confusion, weakness, and unsteadiness on your feet. Severe or sudden cases may produce hallucinations (seeing or hearing things that are not real), fainting, seizures, and coma. If not treated, severe low sodium levels could cause death. Elderly people may be at greater risk
The most common side effects of FETZIMA include:
  • Nausea or vomiting, constipation, sweating, increased heart rate, erectile dysfunction, and palpitations
Tell your healthcare provider if you have any side effect that bothers you or that does not go away. These are not all the possible side effects of FETZIMA. For more information, ask your healthcare provider or pharmacist.

Call your healthcare provider for medical advice about side effects.

Please see Medication Guide within the full Prescribing Information.

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