Major Depressive Disorder

Major depressive disorder (MDD), also known as depression, is a mental health condition characterized by persistent feelings of sadness, hopelessness, and a lack of interest or pleasure in activities.

Definition and Diagnosis

MDD is defined as a mood disorder that interferes with an individual's daily life, causing significant distress and impairment. The diagnosis of MDD is based on the presence of at least five of the following symptoms, which must be present for at least two weeks:

• Depressed mood most of the day
• Markedly diminished interest or pleasure in all, or almost all, activities most of the day
• Significant weight loss or gain
• Insomnia or hypersomnia
• Psychomotor agitation or retardation
• Fatigue or loss of energy
• Feelings of worthlessness or guilt
• Diminished ability to think or concentrate
• Recurrent thoughts of death, recurrent suicidal ideation, or a suicide attempt

Causes and Risk Factors

The exact cause of MDD is not fully understood, but it is believed to involve a combination of genetic, environmental, and psychological factors. Some risk factors that may contribute to the development of MDD include:

• Family history of depression
• History of trauma or stress
• Certain medical conditions, such as chronic pain or sleep disorders
• Substance abuse
• Major life changes or significant losses

Symptoms and Subtypes

The symptoms of MDD can vary from person to person, but common symptoms include:

• Depressed mood
• Anhedonia (loss of interest in activities)
• Changes in appetite or sleep patterns
• Fatigue or low energy
• Difficulty concentrating or making decisions
• Physical symptoms, such as headaches or stomach problems

MDD can be classified into several subtypes, including:

• Melancholic depression: characterized by a loss of interest in activities and a lack of response to pleasurable stimuli
• Atypical depression: characterized by mood reactivity (improvement in mood in response to positive events) and reversed vegetative symptoms (e.g., increased appetite or sleep)
• Psychotic depression: characterized by the presence of psychotic symptoms, such as hallucinations or delusions
• Postpartum depression: occurs in women after childbirth
• Seasonal affective disorder: occurs during the winter months when there is less sunlight

Treatment and Management

Treatment for MDD typically involves a combination of medications, psychotherapy, and lifestyle changes. Medications used to treat MDD include:

• Selective serotonin reuptake inhibitors (SSRIs)
• Serotonin-norepinephrine reuptake inhibitors (SNRIs)
• Tricyclic antidepressants (TCAs)
• Monoamine oxidase inhibitors (MAOIs)

Psychotherapy, such as cognitive-behavioral therapy (CBT) or interpersonal therapy (IPT), can also be effective in treating MDD. Lifestyle changes, such as regular exercise, healthy eating, and stress management, can also help manage symptoms.

Prognosis and Complications

The prognosis for MDD varies depending on the individual and the severity of their symptoms. With treatment, many people are able to recover from MDD and lead fulfilling lives. However, some people may experience chronic or recurrent depression, which can have a significant impact on daily life.

Complications of MDD can include:

• Suicidal thoughts or behaviors
• Substance abuse
• Social isolation
• Difficulty maintaining relationships or employment
• Physical health problems, such as cardiovascular disease or obesity