Major Depressive Disorder

This article offers a comprehensive overview of major depressive disorder, including the symptoms and warning signs, causes, impacts, and treatment approaches. Additional resources and tips for daily living are also discussed.

Key Takeaways:

• Major depressive disorder affects millions of people worldwide and can lead to significant disability and dysfunction if left untreated

• This disorder causes various psychological, behavioral, and physical symptoms, while also increasing the risk of suicidal thoughts and behavior

• Early treatment is essential and should involve a comprehensive approach, often including psychotherapy, medication, and lifestyle/daily habit changes

Understanding Major Depressive Disorder

Major depressive disorder (MDD) is listed under Depressive Disorders in the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5). It is characterized by a combination of mental, behavioral, and physical symptoms, including depressed mood, lack of pleasure or interest, fatigue, sleep and appetite changes, and feelings of guilt or worthlessness.

MDD makes it very difficult to function normally and often negatively affects work and school performance, relationships, mental well-being, and physical health.

Prevalence

MDD is one of the most common mental disorders, affecting around 3.8% of the population, which is nearly 300 million people worldwide. It is now the second leading cause of disability worldwide and is expected to rank as the leading cause by 2030.^[1][2]

The lifetime prevalence is estimated to be between 5 and 17%. Depression is at least 50% more common in women than men, with some estimates suggesting double the prevalence rates for women. It is also more common in older adults, with a prevalence rate of 5.7% for adults over 60.^[1][2]

Symptoms of Major Depressive Disorder

There are many symptoms of major depressive disorder, which can generally be grouped into distinct categories, namely mood/psychological, behavioral, and physical. Out of all of the symptoms, depressed mood and/or anhedonia (lack of pleasure) need to be present for a diagnosis.

Listed below are the primary major depressive disorder symptoms:^[1][2][3]

Mood/Psychological Symptoms

• Depressed mood

• Hopelessness

• Feelings of guilt or worthlessness

• Intense sadness or “emptiness”

• Lack of pleasure or interest in activities

• Irritability or frustration

• Anxiety or restlessness

• Thoughts of suicide or self-harm

Behavioral Symptoms

• Changes in sleep patterns (either trouble sleeping [insomnia] or excessive sleeping [hypersomnia])

• Changes in appetite, which is typically loss of or reduced appetite

• May also include increased cravings for specific foods

• Trouble concentrating

• Fatigue, lethargy, or low energy

Physical Symptoms

• Weight loss or weight gain

• General aches and pains

• Low libido

• Digestive issues

Note: Most of these physical symptoms aren’t necessary for a diagnosis, but still often occur due to the toll depression takes on the body. They are particularly relevant when they exist alongside the above psychological and behavioral symptoms.

Immediate Risks and Support

Depression can result in severe risks that require immediate attention and support. This includes thoughts about hurting yourself or attempting suicide, or thoughts about hurting others.

If you think you might hurt yourself or attempt suicide, it’s essential to call 911 in the US or your local emergency number as soon as possible.

If you’re having suicidal thoughts but no immediate plans, support options include:

• In the US, call or text 988 to reach the 988 Suicide & Crisis Lifeline

• You can also use the Lifeline Chat

• Find the suicide helpline in your country by entering it in at the International Association for Suicide Prevention website

Warning Signs of MDD

There are several warning signs of MDD to be aware of, which may indicate an increased likelihood of suicide attempts or self-harm behavior. These include:^[4]

• Increased alcohol or substance use

• Aggressive behavior

• Withdrawal from family, friends, and community

• Dramatic and intense mood swings

• Impulsive or reckless behavior

• Extreme agitation

It’s important to look out for these warning signs if you live with or interact regularly with someone who has MDD.

Causes of Major Depressive Disorder

Major depressive disorder is thought to result from a complex combination of genetic, biological, environmental, psychological, and social factors. Therefore, there isn’t one true cause of depression, nor does this disorder look the same in each person.

Certain genes have been identified as risk factors for developing MDD, especially in susceptible individuals. Having blood relatives with a history of depression, bipolar disorder (BPD), or suicide is also a risk factor, indicating a genetic component.^[1][3]

There are also likely biological causes too. This includes various abnormalities in brain structure and function, as well as low levels of neurotransmitters or disturbances in neurotransmitter systems, such as with serotonin, dopamine, and norepinephrine. Other biological/physical factors include inflammation and elevated stress hormones.^[1][5]

Environmental factors also play a role in MDD development. Certain environmental risk factors include:^[1][2][3]

• Traumatic or stressful events

• Alcohol or substance use

• Lack of close interpersonal relationships

• Having a serious or chronic illness

Psychological factors, such as low self-esteem, pessimism, and being overly self-critical, may also increase the risk of developing depression.^[3]

Is MDD Hereditary?

There is a likely hereditary component with depression. The estimated heritability rate for depression is 30 to 50%, which means that roughly one-third to one-half of the variation in depression is attributable to hereditary/genetic factors.^[5]

Prevention

There are many things you can do to help prevent depression. As genetic factors account for only a portion of depression, environmental factors (i.e. the way you live) have a significant influence on the development of MDD.

Some of the main strategies to help prevent depression include:^[5]

• Adequate sleep

• A healthy, nutrient-rich diet

• Establish quality relationships with family, friends, and coworkers

• Regular exercise

• Mental and emotional development strategies

• E.g. improving positivity, self-esteem, stress resilience

The reason all of these strategies can help prevent depression is that they address many of the causative factors in MDD. Specifically, these strategies help to reduce inflammation, decrease stress hormones, and increase levels of mood-regulating brain chemicals, feelings of social support and self-esteem, and pleasure, to name a few.^[5]

In addition to these tips, it’s important to seek treatment as soon as you start to experience symptoms. This helps to prevent worsening symptoms and, in turn, can lessen the overall impact of the disorder.

Major Depressive Disorder and Adolescence

MDD rates are increasing in adolescents and younger individuals, with one study showing a 60% increase in depression just from 2017 to 2021. Prevention in this age group is particularly important, given that developing depression at a younger age can lead to problems throughout one’s life if not treated.^[6]

In addition to the above lifestyle tips, it’s important for parents or other adults involved in the child’s life to recognize any early signs of MDD, such as irritability or behavioral changes. School-based programs can also teach adolescents about depression and give them self-coping strategies to help manage their emotions and behaviors.^[2][3]

Diagnosing Major Depressive Disorder

Diagnosing major depressive disorder involves a thorough and comprehensive clinical interview and assessment. It is primarily diagnosed based on the patient’s own detailed history, along with a current mental status examination.

Typically, your primary care doctor will screen for depression, and then refer you to a psychiatrist or psychologist for a more thorough evaluation. An initial evaluation by your doctor includes a complete physical examination (including a neurological examination), medical history assessment, and family medical history assessment.^[1]

Lab work is used to rule out physical causes and may include:^[1]

• Complete Blood Count

• Comprehensive Metabolic Panel

• Tests for thyroid hormones (since these play a role in mood, energy, and appetite)

• Test for vitamin D levels

• Urinalysis and toxicology screening to test for substance use

If MDD is still suspected, the next step is a clinical interview, often conducted by a psychiatrist or psychologist. During this interview, your mental health professional will inquire about your current symptoms and behaviors, as well as your medical history, family history, social history, and substance use history.^[1]

MDD Tests and Assessments

Your mental health professional will implement one or more assessments to evaluate your symptoms. Examples of common assessments for MDD are:^[1]

• Patient Health Questionnaire-9 (PHQ-9): This consists of nine questions that relate directly to theDSM-5criteria for depression.

• Hamilton Rating Scale for Depression (HAM-D): This consists of 21 items that assess a multitude of depression symptoms.

• Beck Depression Inventory (BDI): This consists of 21 items related to the main symptoms of depression.

After the clinical interview, symptoms are compared with the diagnostic criteria found in theDSM-5. These criteria are:

• Five or more of the following symptoms that are present during the same 2-week period and are different from usual functioning; and at least one of these is depressed mood or loss of interest/pleasure:

• Depressed mood most of the day, nearly every day

• Significant decreased interest or pleasure in most or all activities, most of the day, nearly every day

• Significant weight loss or weight gain when not dieting (5% or more weight change), OR decrease or increase in appetite nearly every day

• Insomnia or hypersomnia nearly every day

• Psychomotor agitation (e.g. restlessness, racing thoughts) or retardation (e.g. thinking and moving slowly) nearly every day, which is observed by others

• Fatigue or lack of energy nearly every day

• Feelings of worthlessness or guilt nearly every day

• Decreased ability to think or concentrate, or indecisiveness, nearly every day

• Recurrent thoughts of death or suicide, without a specific plan, or a suicide attempt or specific plan for commiting suicide

• Symptoms cause clinically significant impairment or distress in important areas of functioning

• Symptoms are not caused by a substance or medical condition

• At least one major episode is not better explained by schizoaffective disorder and is not the result of schizophrenia spectrum or psychotic disorders

• There has never been a manic or hypomanic episode

Treatment Approaches for MDD

There are many proven treatments for major depressive disorder, including pharmacological, psychological, and combination approaches, as well as brain stimulation and electroconvulsive therapy. These are often combined with lifestyle changes to maximize the benefits.

Pharmacological Treatments

There are several lines of medications that may be beneficial for individuals with MDD, including:^[1][5][7]

• Selective-serotonin reuptake inhibitors (SSRIs): These are the most commonly used medications and are considered a first-line treatment, especially for severe depression.

• Serotonin-norepinephrine reuptake inhibitors (SNRIs): These drugs have broader effects compared to SSRIs and may be especially useful for depression that comes along with physical pain.

• Other less commonly used antidepressants, including:

• Serotonin modulators, such as trazodone

• Atypical antidepressants, such as bupropion

• Tricyclic antidepressants, such as imipramine

• Mood stabilizers and antipsychotics are sometimes included as add-ons

Other new pharmacotherapies, such as ketamine and psilocybin, are currently being researched and have potential benefits. But these haven’t been approved yet due to their lack of definitive evidence.^[5]

Psychological Treatments

Psychological treatments, especially psychotherapy, are often the first treatment option for MDD, especially in mild to moderate cases. While there are various psychological treatment approaches, the two forms of psychotherapy with the most evidence are cognitive behavioral therapy (CBT) and interpersonal therapy (IPT).^[1][7]

CBT helps patients identify and challenge their negative thoughts, beliefs, and behaviors, so that they can change these into healthier, more adaptive ones. It’s particularly helpful for addressing cognitive distortions and dysfunctional behaviors.^[7]

IPT specifically focuses on the power of relationships to help improve depressive symptoms. In this therapy, the first step is to identify the triggers of depressive symptoms, and then help the individual recognize how this is affecting their mood and social functioning. From there, IPT helps the patient strengthen their social skills and support networks to help lessen symptoms and improve functioning.^[7]

Combination Approaches

Combination approaches combine pharmacological treatments with psychotherapy. Combination therapy is particularly helpful for more severe cases of depression and has been shown to significantly decrease the risk of relapse.^[5]

Other Possible Treatments

There are other possible treatments that may be used for MDD, depending on the individual factors and circumstances. These treatments include:^[1][5][7]

• Electroconvulsive therapy (ECT): This is particularly used for more severe or treatment-resistant depression. It involves brief electrical stimulation of the brain.

• Transcranial magnetic stimulation (TMS): This is another option for treatment-resistant depression that has evidence of benefits. It uses magnetic pulses to stimulate specific brain regions.

• Phototherapy: This therapy uses bright light at specific wavelengths to help reduce depressive symptoms

Challenges in Treatment

Despite the many benefits of depression treatments, there are also challenges. For one, many individuals with depression often lack the motivation, desire, or energy to continue with treatment, especially with the psychotherapeutic options since they involve more time and effort.

Pharmacological treatments also have challenges too. For example, it can sometimes take a trial run of multiple medications to figure out the right medication and effective dose. In addition, many medications have side effects, such as headaches, libido changes, and sleep disruption, among others.

In general, it is challenging to find the best treatment plan for each individual, since there are so many factors that underlie each person’s symptoms. That’s why, once a treatment plan is outlined, it’s essential to adhere to it tightly to increase the chance of positive outcomes and to understand if changes need to be made.

Living with Major Depressive Disorder

There are also self-care strategies and habits you can implement to make living with major depressive disorder a bit easier. Just remember that these should always be used in combination with professional treatment.

Some things that may help when living with MDD are:^[2][5]

• Maintain social connection (esp. with family and friends)

• Reach out for support when needed

• Open, honest communication

• Try to partake in activities you enjoy (or used to enjoy) even if it’s just a few minutes

• Try to exercise

• even a brief 5-minute walk is better than nothing

• Maintain a consistent eating and sleeping schedule as best you can

• Focus on personal hygiene and self-care

• Limit technology and social media use, especially at night

When you have MDD, it’s essential to try to practice self-compassion and avoid perfectionistic tendencies. You’re going to have days that are worse than others. And you’re going to have times where you aren’t able to do the things you know are good for your health. Give yourself grace and remember that it’s a gradual process.

As long as you are generally taking steps in the right direction, that’s what counts. Sometimes, it can feel like you’re not making progress, but even if you do just one small thing in the right direction each day or every couple of days, very often this leads to notable progress over time.