Lecture 2 - Biological basis of depression, and how anti-depressant drugs work Flashcards
What is the health gradient?
Higher social position = better health
What are some examples of candidate stressors? (Brunner, 1997)
- Perceived financial strain
- Job security
- Low control and monotony at work
- Stressful life events and poor social networks
- Low self esteem
- Fatalism
Study: The Whitehall II Study
- N=10,306
- Recruited from the British Civil Service in 1985
- Office support staff face more major life events than the most senior positions
- Office support staff face more difficulty paying the bills
- Senior positions believe they can reduce the risk of a heart attack more than office support
Racism as a determinant of health
- Health outcomes distributed unequally among diverse ethnic groups
- Racism is associated with poorer mental health - including depression, anxiety, psychological stress etc
- Racism also associated with poorer general health and physical health
Why might racism be a determinant of health? - potential reasons for the association
- Reduced access to employment, housing, education and risk factors
- adverse cognitive/emotional processes and associated psychopathology
- Allostatic load and concomitant patho-physiological processes
- Diminished participation in healthy behaviours and/or increase in unhealthy behaviours - either directly as stress coping or via reduced self-regulation
- Physical injury as a result of racially-motivated violence
Race and Biological markers of stress
The findings provide support for a mechanistic biopsychosocial approach in understanding the psychological consequences of discrimination
Effects of CBT for stress management on stress and hair cortisol levels in pregnant women: a randomised controlled trial
- Measures hair cortisol levels, perceived stress scale and pregnancy distress questionnaire
- Control group had higher hair cortisol levels pre and post CBT
- CBT PTs had higher pregnancy distress questionnaire scores pre and post CBT but this score drastically decreased from pre to post
- CBT PTs had slightly higher perceived stress pre CBT than control group but significantly less post CBT
Study: Meditation
- N=34
- control condition
- 4 weeks
- Salivary cortisol levels measured at baseline, 2 weeks following acute stressor, and 4 weeks following acute stressor
- For both groups salivary cortisol concentration increase from baseline to 2 weeks and from 2-4 weeks, with the gradient getting less steep as time passes
- The control group had higher salivary cortisol concentration than meditation group at all 3 measurement times
Study: Yoga and Dance
- N=69
- Each participated in one of three 90-min classes
- African dance
- Hatha yoga
- A biology lecture (control group)
- Salivary cortisol levels went up in the dance group and went down in the yoga group
Stayed the same in the biology control group
Key depression facts in the UK
- Depression is more common in women
- Seen in around 2% of young people under age 19
- Costs the Welsh economy £7billion - equivalent to 1.3% of GDP in UK (£25billion)
What are the clinical features of depression according to the DSM-5?
Five or more of the following symptoms during a 2 week period:
- Depressed mood most of the day nearly every day
- Diminished interest or pleasure in all or nearly all activities
- Significant weight loss or weight gain
- Insomnia or hypersomnia nearly every day
- Psychomotor agitation nearly every day
- Fatigue or loss of energy nearly every day
- Feelings of worthlessness or excessive or inappropriate guilt nearly every day
- Diminished ability to think or concentrate or indecisiveness nearly every day
- Recurrent thoughts of death, recurrent suicidal ideation without a specific plan or a suicide attempt or a specific plan for committing suicide
What is a diathesis?
A genetic vulnerability to something
What is the monoamine hypothesis?
- Reserpine was used to lower blood pressure in the 1930s
- A side-effect of reserpine is that it caused depression in 10-15% of patients
- in 1950s it was used as a treatment for SZ to make patients calmer and more co-operative (Kline, 1954)
- Drugs such as iproniazid were used to treat tuberculosis and were found to lift the mood of the patients
- Reserpine lowers monoamines by leakage from vesicles and iproniazid increases monoamines through inhibition of reuptake
What are the monoamine family of neurotransmitters?
- Norepinephrine (NE)
- Serotonin (5-HT)
- Dopamine (DA)
What occurs in the noradrenergic synapse (excitatory)?
- Production of NA
- NA release
- Activation of postsynaptic receptors
- Activation of autoreceptors
- Reuptake into presynaptic neuron
- Breakdown or storage
What occurs in the serotonin synapse (5-HT)?
- Production of 5-HT
- 5-HT release
- Activation of postsynaptic receptors
- Activation of autoreceptors
- Reuptake of excess synaptic 5-HT
- Breakdown or storage
What is the effect of reserpine on the monoamine synapses?
- Reserpine causes monoamines to leak out of the vesicles
- Monoamines are broken down by MAO
- When the presynaptic neuron is activated there is no neurotransmitter available for release
MONOAMINE HYPOTHESIS FOR DEPRESSION - MAJOR DEPRESSION IS DIUE TO A DECREASE IN FUNCTION OF THE MONOAMINE SYSTEM - LOW LEVELS OF AVAILABLE 5-HT OR NA
