Lecture 33: Mood and Mood Disorders Part 1, MDD Flashcards
What are the DSM-IVTR Mood Disorders?
- Bipolar Disorder
- Major Depressive Disorder
- Cyclothymia
- Dysthymic Disorder
- Other mood disorders
What are mood disorders?
Complex biopsychosocial illnesses
- many symptom domains reflect areas of brain dysfunction or over-function - genetic risk may be transmitted - mental and psychosocial phenomena have neurobio correlates and consequences
What are neurobiological correlates of mood?
i. increasing understanding of normal emotional, vegetative and behavioral responeses
ii. general shift from focus of monoamines and neuroendocrinologic factors towards imaging of circuitry and measurement of gene products, like peptides and cytokines
iii. neurobiologic correlates of affective illness may change over time
What is mood?
Mood = a composite of one’s sense of well-being
- involves cognitive, emotional and behavioral components
- important differences in mood “set-points” among individuals (genetic and learned)
What is sadness?
A NORMAL human emotion that accompanies loss or defeat
What is the difference between sadness and “Clinical Depression”?
Sadness should be:
- transient or shorter-lived - readily understandable in context (“I’d feel that way too…”) - should not cause significant impairment - should not be associated with a full syndrome associated signs and symptoms - should be relieved by activities that help engage in desired activities or distract from the negative thoughts/feelings
What is the spectrum of sadness and Mood Disorders?
- Normal Sadness
- Adjustment disorder with depressed mood (hasn’t crossed the threshold to become a syndrome)
- Grief
- Major Depressive Episode (mild-moderate)
- Major Depressive Episode, Severe with Melancholic Features
- Major Depressive Episode, Severe with Psychotic Features
What are the criteria for major depressive episode?
- Sad, low or blue mood – most days for at least 2 weeks OR
- Pervasive loss of interest and diminished pleasure (anhedonia)
Plus at least 4 of following - Fatigue or low energy
- Insomnia or sypersomnia
- Loss of appetite or increased appetite or weight gain
- Psychomotor retardation or agitation
- Poor concentration
- Suicidal Ideation
- Pathological Guilt
What are the clinically important subforms of MDD?
- Neurotic depression (anger turned inward)
- no longer in the nomenclature
- Melancholia (endogenous depression, opposite of neurotic depression)
- Atypical depression (strongly female predominant, chronic)
- Seasonal depression (fall-winter onset)
- can treat with bright light
What are clinically important forms of depression?
- Psychotic depression
2. Chronic depression
What is psychotic depression?
Most severe form of MDD, characterized by delusions and hallucinations
What is chronic depression?
Defined by a duration of symptoms for TWO YEARS or superimposition of a major depressive episode on antecedent dysthymia
What is dysthymia?
Mild Chronic Depression
Depressive Disorders: Epidemiology:
- Lifetime risk: 10-20% (culture dependent)
- Risk increased during times of stressful life events
- risk in women: 1.5-2.0 times greater than men
- Heritable (about two-fold greater risk)
- Risk of chronicity: ~30% will be ill for >2 years
- risk of recurrence: >75% will have multiple episodes
What is the age of onset for MDD?
Around 30, maybe younger
What is the comorbidity of MDD?
Anxiety
Substance abuse disorders
What is Neurosthenia?
Suffering without being able to put that shit into words
Is marriage protective for men or women in depression?
Men
What is the “Kindling” Phenomenon?
The more depression you have, the less it has to do with stressful life events
As you have more depressive episodes
There is an INCREASE risk of depression
And
LESS association with stressful life events
A “kindling” to the depressive state
What is the significance of 5-HTT?
What are the two factors that lead to depression?
What are the two factors that lead to depression?
- Stress
- genetic variation
- 5HTT polymorphism
- BDNF polymorphism
What are the areas of brain that are most pertinent in MDD?
Nucleus accumbens and Anterior Cingulate Cortex
-less activity in depression
What is the purpose of the anterior cingulate cortex (ACC)?
Plays a role in rational cognitive functions such as reward anticipation, decision-making, empathy and emotion
-integrates EMOTIONAL stimuli and ATTENTIONAL function
What does your mood state do to your ability to draw upon memories?
The worse your mood, the worse the memories you draw upon in hippocampus lol
What type of cortical variation do you see in patients with MDD?
SMALLER hippocampal volumes
32% have SMALLER medial orbitofrontal cortices (MOFC)
-more activity in amygdala and VLPFC
-less activity in ACC and nucleus accumbens
How do you cause cortex to shrink without cell death?
Stress could cause decreased connectivity and a constricting effect on the NEUTROPIL
What happens when you are chronically stressed?
Chronic activation of the stress-response system causes a variety of adverse effects in the brain and mediates many of the physiologic and behavioral responses in depression
Example: increased despair = decreased sex, sleep, eating, immune function
Increased BP, HR, blood sugar
What is the association between the HPA axis and depression?
Depressed patients have HPA HYPERACTIVITY
CRF is hypersecreted to mediate some behavioral symptoms of depression
What does stress and depression do?
Result in neuronal atrophy and cell death caused by LESS BDNF activity
What is BDNF? Significance?
Brain-derived Neurotrophic Factor
-critical for growth and function of the nervous system
-expressed in neurons and glia
-as well as learning and memory
Less BDNF = more depression
BDNF polymorphism = decreased hippocampal volume
What do antidepressants do?
They normalize BDNF levels
Decrease Glucocorticoid levels
Leads to neuronal survival
This is because serotonin and other monoamines may be involved in regulating synthesis/release of BDNF
What happens to BDNF level once you treat MDD?
You may restore BDNF function
What is depression a risk factor for?
Post-MI mortality
Nursing Home Survival
Poor stroke recovery
What are the two polymorphisms to keep an eye on for MDD?
5-HTT polymorphism = less serotonin = more depression from stress
BDNF polymorphism = less BDNF = more neuronal death = more depression
When someone has an enlarged ACC, what are depression implications?
Greater volume and activity of ACC
Associated with faster treatment response
So treat early
