What is Major Depressive Disorder?
Major depressive disorder (MDD), also known as depression, is a significant health issue. In fact, the World Health Organization ranked it as the third leading cause of global disease burden in 2008, and predicts that it will be in the first place by 2030. Signs that someone might have MDD include a continuously low or sad mood, losing interest in activities they once enjoyed, feeling worthless or excessively guilty, lacking energy, struggling to focus, changes in appetite, slow movement or restlessness, sleep problems, or thoughts of suicide.
According to the Diagnostic and Statistical Manual of Mental Disorders, 5th Edition (a book that doctors use to diagnose mental health conditions), a person needs to have at least five of these symptoms to be diagnosed with MDD. One of these symptoms has to be a depressed mood or a loss of pleasure, known as anhedonia. These symptoms should be serious enough to disrupt work, school, or relationships. Additionally, any history of a manic or hypomanic episode (periods of abnormally high energy or mood) must be excluded to diagnose MDD. Children and teenagers with MDD might show their depression as an angry or irritated mood.
The manual also lists other types of depression including:
* Persistent depressive disorder, which was previously referred to as dysthymia
* Disruptive mood dysregulation disorder
* Premenstrual dysphoric disorder
* Depressive disorder caused by substance use or medication
* Depressive disorder caused by another medical condition
* Unspecified depressive disorder
What Causes Major Depressive Disorder?
Major depressive disorder (MDD) or depression is believed to have many causes, including biological, genetic, environmental, and mental health factors. In the past, people thought that depression was mainly due to an imbalance in certain chemicals in the brain, especially serotonin, norepinephrine, and dopamine. This theory was supported by the effectiveness of antidepressants, which increase the levels of these neurotransmitters, in treating depression. Moreover, people at risk of suicide were found to have low levels of serotonin. However, recent theories suggest that depression is mainly linked to more complex brain functions and pathways, which then leads to disturbances in neurotransmitter systems.
Other chemicals in the brain known as neurotransmitters – GABA, which slows down brain activity, and glutamate and glycine, which speed it up – are also thought to play a role in depression. Depressed individuals have been found to have lower levels of GABA in their blood, cerebrospinal fluid (fluid around the brain and spinal cord) and brain. GABA is thought to have an antidepressant effect by slowing down certain pathways in the brain related to emotions and thought processing. Medications that block (antagonize) NMDA receptors (a type of glutamate receptor) have been researched and found to have antidepressant properties.
Abnormalities in thyroid and growth hormones have also been linked to depression. Experiencing multiple stressful events or trauma during childhood is associated with the risk of developing depression later in life. Severe stress early in life can cause significant changes in the brain and behavior, which may lead to severe depression later.
Brain imaging of individuals with depression has shown increased activity in the deeper regions of the brain and decreased activity on the left side of the front part of the brain.
Twin studies, as well as family and adoption studies, have suggested that genes also play a role in depression. Genetic studies show that identical twins are very likely to both have depression.
Certain life events and personality traits also play a major role in depression. For example, the “learned helplessness” theory suggests that depression can occur in people who frequently find themselves in situations they cannot control. According to cognitive theory, depression can occur as a result of distorted thinking in people who are susceptible to depression.
Risk Factors and Frequency for Major Depressive Disorder
Major depressive disorder (MDD) is a common mental health condition. It affects between 5 and 17% of people at some point in their lives, with an average of 12% of people experiencing it. It’s about twice as common in women than men, possibly because of factors such as hormonal differences, the impact of giving birth, different stressors faced by men and women, and learned behaviors. On average, people start experiencing MDD around the age of 40, but it’s becoming increasingly common in younger people due to factors like alcohol and drug use.
MDD is more prevalent in people who don’t have strong personal relationships, or who have gone through a divorce or separation, or lost their partner. Regardless of race or socioeconomic status, anyone can get MDD. People with MDD often have other mental health conditions as well, such as substance use disorders, panic disorder, social anxiety disorder, or obsessive-compulsive disorder. If someone with MDD has other mental health conditions, they are at a greater risk of suicide. In older adults, depression is especially common in those with other medical conditions. Depression is also more common in rural areas than in urban ones.
Signs and Symptoms of Major Depressive Disorder
Diagnosing major depressive disorder mainly relies on the information provided by the patient during clinical interviews and mental status examinations. These discussions should cover the patient’s medical history, family background, social circumstances, and any substance use, alongside their specific symptoms. Information gathered from family members or friends can also be crucial for a thorough evaluation.
Doctors should perform a complete physical examination, including a neurological test, to rule out other potential causes of depressive symptoms. It’s crucial to understand the full medical and psychiatric history of the patient and their family. A mental status examination, a type of assessment that evaluates a patient’s emotional wellbeing and mental capacity, is a crucial component in diagnosing and evaluating major depressive disorder.
Testing for Major Depressive Disorder
While there’s no definitive test to identify depression, doctors typically use a mix of lab tests and assessments to diagnose it. These can include a complete blood workup and tests to track thyroid function, vitamin D levels, and any signs of drug use. These help to rule out any other medical conditions that might be causing feelings of depression.
Many people visit their family doctors with physical symptoms that turn out to be related to depression. Sometimes, they don’t recognize they are feeling depressed and are instead taken for treatment by a family member or referred by an employer. As such, it’s important to also keep an eye out for social withdrawal and decreased activity. Moreover, whether or not they mention feeling depressed, it’s crucial to check if they’re having any thoughts of suicide or harm to others.
In a typical doctor’s office, they may use a questionnaire called the PHQ-9. It is a self-reporting tool that a patient fills out, which can guide the doctor in diagnosing depression and assessing its severity. The PHQ-9 consists of nine questions about symptoms and feelings based on the official criteria for depression. It scores from 0 to 27, and a score of 10 or higher suggests possible depression.
In hospitals, the Hamilton Rating Scale for Depression (HAM-D), filled out by a healthcare provider, is often used. This scale features 21 items relating to symptoms of depression, though the final score only relies on the first 17 items. Additional tools can include the Montgomery-Asberg Depression Rating Scale (MADRS), the Beck Depression Inventory (BDI), and the Zung Self-Rating Depression Scale, among other questionnaires.
Treatment Options for Major Depressive Disorder
Major Depressive Disorder (MDD), or severe depression, can be treated with a variety of approaches including medication, talking therapies, physical treatments, and lifestyle changes. Usually, the starting point for treating MDD is a combination of differently kinds of treatments or therapies– both medication and talking therapy. This has been found to be more successful than just one or the other. Electroconvulsive therapy (ECT), where an electric current is passed through the brain to cause a seizure, can also be used and it has proved to be very effective for severe MDD.
There are different kinds of medications approved for treating MDD. All of them essentially play the same role in managing the disorder but they have slightly different side effects. You have the Selective serotonin reuptake inhibitors (SSRIs), like fluoxetine, sertraline and others, which are the most commonly prescribed. You also have Serotonin-norepinephrine reuptake inhibitors (SNRIs) which are often used in patients who have depression along with pain disorders. There’s also Serotonin modulators, Atypical antidepressants and other types which can be used. The doctor will prescribe what they think will work best for the patient’s unique situation.
Then we have what is called psychotherapy, or talk therapy in its basic form, which involves connecting and talking with a mental health professional. Cognitive-behavioral therapy and Interpersonal therapy are examples of this.
In addition to ECT, we have other physical therapies like Transcranial Magnetic Stimulation (TMS) and Vagus Nerve Stimulation (VNS). TMS is FDA-approved for cases of MDD that haven’t improved with medication trials. Similarly, VNS is also FDA-approved, but for long-term use in cases of MDD that have not improved despite trying at least four medication trials.
Finally, we have a specific medication known as Esketamine, which is a nasal spray to be used alongside an oral antidepressant for MDD that hasn’t improved with other medications.
What else can Major Depressive Disorder be?
When checking for Major Depressive Disorder (MDD), many other conditions must be ruled out to make sure the right treatment is given. These conditions include other kinds of depression caused by medical conditions or substances, long term but low intensity depression (dysthymia), mood changes following a major life change (adjustment disorder with depressed mood), and other conditions like bipolar disorder, schizophrenia, anxiety disorders, and eating disorders.
Depressive symptoms can also be caused by different reasons, such as:
- Neurological conditions like stroke, multiple sclerosis, bleeding under the layer covering the brain, epilepsy, Parkinson’s disease, and Alzheimer’s disease
- Diseases related to hormone-producing glands such as diabetes, thyroid disorders, and adrenal disorders
- Changes in body’s chemical balance such as high calcium levels in blood, low levels of sodium in the blood
- Substance and medication-related like prolonged use of steroids, high blood pressure medicines, seizure medicines, antibiotics, sedatives, hypnotics, alcohol, and withdrawal from stimulant substances
- Nutrition-related causes such as deficiency of vitamin D, B12, B6, iron, or folic acid
- Infections such as HIV and syphilis
- Certain types of cancer
What to expect with Major Depressive Disorder
Untreated major depressive disorder (MDD) can persist from 6 to 12 months. Around two-thirds of those affected contemplate suicide, and 10 to 15 percent sadly take their own lives. The illness often reoccurs, with about half of the patients experiencing a relapse after the first episode, 70% after the second episode, and 90% after the third episode. About 5 to 10 percent of people with MDD eventually develop bipolar disorder, which is a condition characterized by extreme mood swings.
The chances of successfully treating MDD are generally good in individuals experiencing mild episodes, those without psychotic symptoms (severe mental disorientation), adhere strictly to their treatment program, have a robust support network, and previously had strong mental health (referred to as good premorbid functioning).
However, the outlook is less favorable in patients with another mental health problem alongside MDD, personality disorders, several hospital admissions, and those diagnosed at a later stage in life.
Possible Complications When Diagnosed with Major Depressive Disorder
Major depressive disorder (MDD) is a prevalent health issue that greatly affects everyday life. It can cause significant difficulties with daily functioning and negatively impacts relationships, reducing overall life quality.
People with MDD are more likely to encounter additional mental health issues – anxiety disorders and substance abuse disorders. This can also increase the likelihood of suicidal thoughts or actions. Depression can also worsen other health conditions, such as diabetes, high blood pressure, chronic lung diseases like COPD, and heart disease.
Moreover, people dealing with depression often display self-destructive behavior as a way of dealing with their feelings. Without proper treatment, MDD can be incredibly disabling.
Common consequences:
- Difficulty with daily functions
- Negative impact on relationships
- Lower life quality
- Risk of anxiety disorders and substance abuse
- Potential threat of suicide
- Aggravation of existing health conditions
- Self-destructive behavior
- Possibly debilitating if untreated
Preventing Major Depressive Disorder
Educating patients about their health conditions can significantly influence how well they manage these conditions, especially in the case of major depressive disorder (MDD). MDD, a type of mental health condition that can cause feelings of extreme sadness and a loss of interest in life, is a common cause of disability around the globe. Unfortunately, in many places, there is a stigma around mental health issues which can make people wary of discussing their feelings of depression or seeking help.
Because of this, it’s incredibly important that patients understand their mental health condition. Education can help them understand what they’re experiencing and why, as well as how treatment can help them. This understanding can also help them stick to their treatment plan better.
Educating the family members of patients is also a crucial step in managing MDD effectively. Families who understand the condition can provide better support and care to their loved ones, increasing the likelihood of successful treatment.
