Study Notes on Depressive and Bipolar Disorders

Depressive and Bipolar Disorders

Unipolar Depression and the Depressive Disorders

How Common Is Unipolar Depression?

  • Approximately 8% of adults in the United States experience severe unipolar depression annually.

  • Around 5% display mild forms of unipolar depression.

  • 20% of adults experience an episode of severe unipolar depression at some point in life.

  • Prevalence rates are similar across various countries, including Brazil, Canada, England, and France.

  • Higher rates are noted among individuals of limited economic means compared to affluent individuals.

  • Women are over twice as likely as men to experience severe unipolar depression (26% of women versus 12% of men).

  • Higher occurrences are also found in transgender and nonbinary populations compared to cisgender individuals.

Symptoms of Depression

  • Life seems dark; challenges feel overwhelming.

  • Symptoms span across five areas: emotional, motivational, behavioral, cognitive, and physical.

    • Emotional Symptoms: Common experiences include feelings of sadness, emptiness, humiliation, and anhedonia (loss of pleasure).

    • Motivational Symptoms: Loss of interest in usual activities; notable lack of drive and initiative. Suicide risk is significantly higher, estimated 17 times that of non-depressed individuals.

    • Behavioral Symptoms: Less activity and productivity; social withdrawal; may speak and move slowly.

    • Cognitive Symptoms: Negative self-views, pervasive pessimism, blame for misfortunes; cognitive difficulties (e.g., memory, attention).

    • Physical Symptoms: Common ailments include headaches and digestive issues; sleep and appetite disturbances are prominent.

Diagnosing Unipolar Depression

  • **DSM-5-TR Criteria for Major Depressive Episode:

    1. Duration: 2 weeks or more, with increase in depressed mood and/or loss of pleasure.

    2. At least 3 or 4 additional symptoms: weight/appetite change, sleep disturbances, fatigue, feelings of worthlessness, and recurrent thoughts of death/suicide.

    3. Significant distress or impairment in functioning.**

  • Major Depressive Disorder: History of a major depressive episode without mania/hypomania.

  • Persistent Depressive Disorder: Chronic symptoms persist for at least 2 years. Symptoms cannot be absent for more than 2 months at a time.

Stress and Unipolar Depression

  • Episodes often trigger in response to stressful life events.

  • Studies show 80% of severe episodes occur following significant negative events.

  • Distinctions are made between reactive (exogenous) and endogenous depression.

The Biological Model of Unipolar Depression

  • Genetic Factors: Family studies show about 30% of relatives of depressed individuals also suffer depression.

  • Biochemical Factors: Low activity of norepinephrine and serotonin is linked to depression. Glutamate is also involved in neuronal communication.

  • Brain Circuits: Dysfunction in brain structures (e.g., prefrontal cortex and amygdala) is implicated in unipolar depression. Low neurotransmitter activity disrupts this circuit, characterized by both overactivity in some areas and underactivity in others.

Treatments for Unipolar Depression

  • Biological Treatments: Common options include:

    • Antidepressants (MAO inhibitors, tricyclics, SSRIs): e.g., Prozac increases serotonin.

    • Ketamine-based treatments: Rapid relief from depression; IV or nasal spray (esketamine).

    • Brain Stimulation:

    • Electroconvulsive Therapy (ECT): Effective for severe depression despite controversy due to associated memory loss.

    • Vagus Nerve Stimulation (VNS) and Transcranial Magnetic Stimulation (TMS).

Psychological Models of Unipolar Depression

  • Psychodynamic Model: Links depression to unresolved grief, introjection, and symbolic loss. Unconscious processes are believed to drive depressive symptoms.

  • Cognitive-Behavioral Model: Focus on negative thinking patterns. Includes:

    • Learned Helplessness: Linked to internal attributions during negative events.

    • Cognitive Triad: Negative interpretation of experiences, self, and future leads to depression.

    • Behavioral Activation: Aims to increase rewarding activities to alleviate symptoms.

Sociocultural Model of Unipolar Depression

  • Links depression to social context, family dynamics, and multicultural factors (e.g., gender, race). Interpersonal and cultural elements heavily influence experiences and reports of depression.

Integrating Models: The Developmental Psychopathology Perspective

  • Proponents see factors (biological, psychological, sociocultural) as interconnected through development, with early negative factors influencing later ones.

    • Support comes from resilience in individuals facing adversities.

Conclusion

  • Treatment efficacy varies, with cognitive-behavioral therapies showing substantial success among all forms of depression. Understanding unipolar depression benefits from a holistic view of its models and factors, taking into account individual experiences, challenges, and cultural contexts.