Diagnoses explanation

Full Answer Section

• • Personality traits: Some personality traits, such as low self-esteem or being overly critical of oneself, may increase vulnerability.
  • Substance abuse: A history of substance abuse can co-occur or exacerbate depressive symptoms.

Pathophysiology (including classic signs and symptoms)

The pathophysiology of MDD is complex and not completely understood. Current theories focus on:

• Neurotransmitter dysregulation: Imbalances in serotonin, norepinephrine, and dopamine affect mood, motivation, and reward pathways.
• Neurotrophic factors: Reduced levels of brain-derived neurotrophic factor (BDNF) may impair neuronal plasticity and resilience.
• Structural and functional brain changes: Studies have shown differences in brain activity and structure in certain areas of the brain (e.g., prefrontal cortex, hippocampus, amygdala) in people with depression.
• HPA axis dysregulation: The hypothalamic-pituitary-adrenal (HPA) axis, involved in the stress response, may be overactive in depression, leading to elevated cortisol levels.

Classic Signs and Symptoms: A person must experience five or more of these symptoms during the same 2-week period, with at least one of the symptoms being either (1) depressed mood or (2) loss of interest or pleasure:  

• Depressed mood: Sadness, emptiness, hopelessness, irritability (especially in children and adolescents).
• Loss of interest or pleasure: Anhedonia, inability to experience joy or satisfaction.
• Significant weight loss or gain: When not dieting, or decrease or increase in appetite nearly every day.
• Insomnia or hypersomnia: Difficulty sleeping or sleeping too much.  
• Fatigue or loss of energy: Feeling tired even after minimal exertion.
• Feelings of worthlessness or excessive guilt: Self-blame, negative self-perception.
• Difficulty concentrating: Trouble thinking, making decisions, or remembering things.
• Psychomotor agitation or retardation: Observable by others, not merely subjective feelings of restlessness or being slowed down.  
• Recurrent thoughts of death or suicide: Suicidal ideation, attempts, or a specific plan for committing suicide.

Physical Assessment and Testing to Confirm the Diagnosis

MDD is primarily a clinical diagnosis based on a thorough psychiatric evaluation. There isn't a single "test" for depression. However, some assessments and tests may be used:

• Mental status exam: Assesses mood, affect, thought processes, cognition, and insight.
• Depression rating scales: Questionnaires like the Beck Depression Inventory (BDI) or the Hamilton Rating Scale for Depression (HAM-D) can help quantify the severity of depressive symptoms.
• Physical exam: To rule out underlying medical conditions that may be contributing to depression.
• Laboratory tests: Blood tests (e.g., thyroid function tests, vitamin B12 levels) may be done to exclude medical causes of mood changes.

Differential Diagnoses

It's important to differentiate MDD from other conditions that may present with similar symptoms:

• Bipolar disorder: Distinguishing between unipolar depression (MDD) and bipolar depression is crucial, as treatment differs significantly.
• Adjustment disorders: Mood disturbances related to a specific stressor, but symptoms are less severe and resolve when the stressor is removed.
• Grief: Normal feelings of sadness after a loss, which typically improve over time.
• Hypothyroidism: Can cause fatigue, low mood, and cognitive difficulties.
• Substance abuse: Depressive symptoms related to drug or alcohol use.
• Anxiety disorders: Can co-occur with depression and share some symptoms.

Gold Standard for Treatment of MDD

The gold standard for treating MDD typically involves a combination of:

• Psychotherapy: Cognitive Behavioral Therapy (CBT) and Interpersonal Therapy (IPT) are effective therapies that address negative thought patterns and improve coping skills.
• Pharmacotherapy: Antidepressant medications (e.g., SSRIs, SNRIs, tricyclic antidepressants) can help regulate neurotransmitter imbalances and alleviate symptoms. The choice of medication is individualized based on symptom profile, side effect profile, and patient preference. It's important to note that antidepressants take several weeks to reach their full effect.
• Lifestyle changes: Regular exercise, a healthy diet, adequate sleep, and stress management techniques can support recovery.

In some cases of severe or treatment-resistant depression, other interventions may be considered, such as electroconvulsive therapy (ECT) or transcranial magnetic stimulation (TMS). The most effective treatment plan is tailored to the individual's specific needs and circumstances.

Sample Answer

Definition of Major Depressive Disorder (MDD)

Major Depressive Disorder (MDD) is a common and serious mental illness that negatively affects how you feel, the way you think, and how you act. It causes persistent feelings of sadness and loss of interest or pleasure, which can lead to a variety of emotional and physical problems. These symptoms must be present for at least two weeks and cause significant impairment in social, occupational, or other important areas of functioning to be diagnosed as MDD. It's important to distinguish MDD from normal feelings of sadness or grief, which are transient and usually related to a specific event.

Prevalence and Risk Factors

• Prevalence: MDD affects millions of people worldwide. It's estimated that approximately 5-7% of adults experience MDD in any given year. Women are more likely to be diagnosed with MDD than men.
• Risk Factors: The exact cause of MDD isn't fully understood, but it likely involves a combination of factors:
  • Genetics: A family history of depression increases the risk.
  • Brain chemistry: Imbalances in neurotransmitters (e.g., serotonin, dopamine, norepinephrine) are thought to play a role.
  • Environmental factors: Stressful life events, trauma, abuse, and social isolation can trigger or worsen depression.
  • Medical conditions: Certain medical illnesses (e.g., thyroid disorders, chronic pain) can contribute to depression.