Mood Disorders Flashcards
What are two examples of affective disorders?
- Major depressive disorder
- Bipolar disorder
What percentage of the world popultation suffers from major depressive disorder?
2-7
What percentage of the world suffers from bipolar disorder?
1
Which gender is MDD more common in and by how much?
2X more common in women than men
What is the main peak age for MDD?
30-40 (but is decreasing)
What age is the onset of bipolar disorder?
15-19 (rarely after 40)
Which sex is more likely to have bipolar disorder?
They are equal!
What are the three largest economic burdens of depression?
- Direct healthcare costs
- Suicide costs
- Workplace costs (largest)
What are the three main medical costs of depression?
- Treatment costs of major depressive disorder
- Other depressive disorders
- Comorbidities such as heart disease or other psychiatric illnesses
What are the two psychiatric diagnostic manuals used?
- DSM-5 (american psychiatric society)
- ICD-11 (World health organisation)
What are the two categories of mood disorders?
- Low mood
- Elevated mood and low mood
What are two examples of mood disorders that fall under ‘low mood’?
- Major depressive diorder
- Dysthymia
What is an example of a disorder that fall under ‘elevated mood and low mood’ category of mood disorders?
Bipolar disorder
What are the two necessary DSM-5 symptoms in order to be diagnosed with MDD?
- Depressed mood
- Diminished interest or loss of pleasure in almost all activities (anhedonia)
Give some examples of other diagnostic points for MDD
- Significant weight change or appetite disurbance
- Sleep disturbance
- Psychomotor agitation or retardation
- Fatigue or loss of energy
- Feelings of worthlessness
- Diminished ability to concentrate
- Recurrent thoughts of death
What is the diagnostic criteria for MDD
In a two week period, must have 5 of the symptoms which must cause distress or impairment and do not have another cause.
What do diagnostic specifiers aim to acheive?
They make the diagnostic more precise
What are some examples of diagnostic specifiers?
MDD with
- Anxious distress
- Atypical features
- Post-partum onset
- Seasonal pattern
What are some diagnostic specifiers to do with the severity/course of the MDD?
- Mild
- Moderate
- Severe
- With Psychosis
- In partial remission
- In full remission
- Single/recurrent
How does NICE diagnose MDD?
- Uses the DSM-5
- Based on the Patient Health Questionnaire 9 further stratifies depression as:
- Less severe (PHQ-9<16)
- More severe (PHQ-9>16)
What is another name for bipolar disorder?
Manic depression
What two periods of mood does bipolar consist of?
Depressive episodes
and
Manic episodes
How are the depressive episodes of bipolar disorder diagnosed?
Using the same criteria as MDD
What percentage of people with bipolar disorder attempt suicide?
35%
What is the key diagnostic criteria for bipolar disorder manic episodes?
- Abnormally elevated, expansive or irritable mood and persistently increased activity or energy, present most of the time for at least a week
- Need three or four (if irritable mood) of the other critereon
- Episode causes marked impaiment to functioning or has psychotic features
List some diagnostic criteria for manic episodes
- Inflated self esteem, grandiosity
- Decreased need for sleep
- More talkative than usual
- Flights of ideas, racing thoughts
- Distractibility
- Increase in goal directed activity or psychomotor agitation
- Excessive involvement in damaging activities
What are two mania subtypes?
- Hypomania
- Mixed episode
What is Hypomania?
- Often seen as a personality trait rather than a disorder
- Mildly elevated mood and energy levels
- Must produce definite change in functioning that is noticeable by others
- Impairment not so great: individuals can be highly productive whilst hypomanic
What is mixed episode as a mania subtype?
- Patient has elevated energy levels, psychosis but is simultaneously depressed
- Even higher risk of suicide
What are the 3 Bipolar disorder subtypes?
- BP type 1
- BP type 2
- Cyclothymia
What are the characteristics of BP type 1?
- ‘Classic manic depression’
- Also a possibility of rapid cycling (>4 episodes in a year)
What are the characteristics of BP type 2?
- Depressive episodes and hypomania
- Can also get rapid cycling (>4 episodes in a year)
What are the characteristics of Cyclothymia?
- Mild depression and hypomania for more than 2 years
What does BP disorder being labelled the ‘mad genius’ condition mean?
There is a link between BP disorder to creativity
Which areas of the brain atrophy during MDD?
- Prefrontal cortex
- Hippoampus
- Anterior Cingulate Cortex
- Amygdala
What happens to hippocampal volume in MDD when people are not treated?
Hippocampus decreases by about 30%
What occurs to glucose metabolism in the prefrontal cortex during MDD and why is this linked to MDD?
There is lower glucose metabolism due to the reduction of cell numbers in that region
Prefrontal cortex exerts inhibitory control of the hypothalamus (regulates cortisol) and emotion- therefore it is less regulated when less metabolism
What happens to brain activity of the PFC in the different phases of bipolar disorder?
- Activity is decreased during a depressive phase
- Activity is increased during a manic episode
What can happen to MDD if the Ventral PFC is lesioned?
Can illeviate the depression
How is the Amygdala functionally different in depression?
Volume is reduced in major depressive disorder
How is Amygdala activity different in major depressive disorder?
The amygdala is overactive to sad stimuli and underactive to happy stimuli
Due to endocrine ties, the amygdala when overactive influences the production of cortisol
What is the monoamine hypothesis?
MDD is the dysfunction of serotonerfic and noradrenergic transmission
What is chronic stress as a mechanism of depression?
- Dysfunction of the HPA axis
- Errors witht the prefrontal cortex and hippocampus
What is Iproniazid?
- Developed to treat TB
- Patients seemed innapropriately happy
- Approved as an anti depressant in 1958
- Is an irreversible MAO inhibiter
What is Reserpine?
- Early antihypertensive and antipsychotic
- Blocks vesicular monoamine transporter (VMAT) and depletes MA
- Suggested to cause depression
What occurs when there is a depletion of tryptophan?
- Lowers mood
- Induces relapse
What are two bits of supporting evidence for the monoamine hypothesis?
- Almost all antidepressant drugs act by altering serotonergic or noradrenergic transmission
- Effects on transmission are very quick
What is the main problem with the monoamine hypothesis?
- Antidepressant effects are delayed by 2-4 weeks
- The hypothesis tries to explain this by changes in receptor expression and desensitizatoin
What does HPA stand for?
Hypothalamic Pituitary Adrenal Axis
What hormone does the hypothalamus produce in the HPA axis and what does it target?
- CRF (Cortisol releasing factor)
- Targets the anterior pituitary gland
What hormone does the pituitary gland produce in the HPA axis and what does it target?
- ACTH (adrenocorticotrophic hormone)
- Targets the adrenal cortex
What hormone does the adrenal cortex produce in the HPA axis and where does it act?
- Cortisol
- Acts as a negative feedback loop to glucocorticoid receptors in the hypothalamus and pituitary gland
How can we increase cortisol production via the HPA axis?
- Increase stress
What percentage of depressed patients have hyperactivity of the HPA axis?
50
What percentage of severely depressed patients have HPA axis hyperactivity?
80
What is the Dexamethasone suppression test?
- Dexamethosome is a potent syntheic glucocorticoid which acts on receptors in the pituitary and hypothalamus
- It acts to reduce the cortisol
- In a control it will reduce their cortisol by 85%
- In a depressed individual it will decrease cortisol byb 45% (negative feedback loop isn’t working correctly)
How does chronic stress reduce the feedback loop?
Elevated levles of hydro cortisol over a long period of time compromises the feedback loop and dramatically increases cortisol and CRF
What two areas important for emotion regulation have receptors for cortisol and what does increased cortisol cause in these areas?
- Hippocampus
- Prefrontal cortex
- Both have increased apoptosis
- Both have decreased neurogenesis
- Causing atrophy and depression
What is Cushing’s syndrome?
- Increased cortisol, with long term glucocorticoid treatment
What is a common co-morbidity with cushing’s disease?
Depression
What areas act to regulate the HPA axis and no longer do this in depressed individuals?
- Prefrontal cortex
- Hippocampus
- Amygdala
- Loss of regulation into the hypothalamus
What is the main genetic factor associated with the HPA axis problem?
Polymorphisms in HPA genes
What causes epigenetic factors in the HPA axis problem?
- Childhood trauma and deprivation
- These cause hyperactivity of the HPA which can persist into adulthood
- Can even predict later depression based on these early origins
How do antidepressant drugs work to regulate the HPA axis?
- Act via monoamine transmission, infleuncing the rate of apoptosis and neurogenesis
- These then restore structures of the brain
- When these are bacl working, the HPA axis may come under control and will further promote neurogesis and decrease apoptosis
- This decreases the cortisol and CRF levels
What is concordance in terms of twin studies?
The percentage chance that one twin will develop a disorder if the other twin already has it