Mental Illness Flashcards
Neurological vs. psychiatric disorders
- Neurological have organic lesion, single brain area damaged, single cause (e.g. infection)
- Psychiatric have no organic lesion, CBT can treat to varying degrees
Anxiety disorders
- Encompasses generalized anxiety disorders, OCD, phobias, and more
- Most common psychiatric disorder
- Sympathetic activation
- HPA axis activation
HPA axis
- Involved in release of cortisol (stress hormone)
- Hypothalamic release of CRH → pituitary release of ACTH → adrenal release of cortisol
How is cortisol measurable?
In saliva (when stress increases, cortisol levels increase)
Cortisol relation to glucose
- Cortisol is a glucocorticoid → increases glucose levels in blood, released from adrenal cortex of kidney
- Binds to glucocorticoid receptors (GCRs) in the body and brain
HPA axis and amygdala
The amygdala is involved in emotional response (esp stressful situations), helps combine stimuli to decide if stress response should happen
- Outputs of system activate HPA axis and sympathetic nervous system
- Damage to amygdala decreases stress response
- Inappropriate activation of amygdala has been associated with anxiety disorders
Dysregulation of HPA axis
Chronic activation of HPA axis results in chronically elevated cortisol levels → can result in maladaptive changes in HPA axis
Role of hippocampus in HPA axis
- Cortisol interacts with G-protein-coupled receptors on hippocampal cells
- Hippocampus inhibits activation of HPA axis → can get loss of negative feedback over HPA axis
- Thus, hippocampal atrophy (decrease in volume) is associated with anxiety disorders
- High levels of cortisol have been associated with down-regulating birth of new cells (hippocampus is one of few sites of neuronal synthesis) or speeding up death of old cells
- Electrical activity in PFC (affects amygdala and hippocampus) also associated with anxiety disorders
What happens to the hippocampus during chronic activation of the HPA axis?
a) Increased neurogenesis
b) Atrophy and reduced feedback on the HPA axis
c) Increased activity to counter stress response
d) Overactivation leading to heightened anxiety
b) Atrophy and reduced feedback on the HPA axis
Categories of drug treatments for anxiety disorder
- Benzodiazepines
- Imidazopyridines
- SSRIs
Response rate to anxiolytic drugs (benzos, etc)
High response rate (80%)
Benzodiazepines
- E.g. valium
- Give immediate response
- Activate GABA channels (inhibitory), which causes a greater influx of Cl-
- Ethanol can also bind to these channels → explains why people can sometimes self-medicate with alcohol
- Labelling with radioactive benzodiazepines demonstrates that brain of person with anxiety disorder (right brain) has lower concentration of GABA receptors (may correlate with intensity of anxiety disorder)
What NT do benzos activate?
GABA
Brains of people with anxiety disorders have a ___ concentration of GABA receptors
Lower
Imidazopyridines
- Z-drugs
- Give immediate response
- Binds to the same site as benzodiazepines and increased Cl- influx but with fewer side effects
Which has more side effects: benzodiazepines or imidazopyridines?
benzodiazepines
SSRIs
- E.g. Prozac and tricyclic antidepressants including monoamine oxidase
inhibitors i.e. MAOIs - Give delayed response (6-8 weeks)
CBT for anxiety
- Delayed response
- Experience dependent plasticity (target particular behavior or deal with specific set of stimuli) → altering learned responses
- Gold standard therapy
Diagram of GABA-gated CL- channel mechanism
Also used to treat insomnia and epilepsy
Which of the following statements about anxiety disorder treatments is TRUE?
A. Benzodiazepines activate GABA channels, leading to an immediate response but carry a risk of addiction.
B. Ethanol binds to the same site as benzodiazepines, which may explain why some people self-medicate with alcohol.
C. Imidazopyridines bind to the same site as benzodiazepines and decrease chloride influx, resulting in fewer side effects.
D. SSRIs, such as Prozac, provide relief for anxiety symptoms but have a delayed response of 6-8 weeks.
E. More than one of the above.
F. All of the above.
E. More than one of the above.
Medication and CBT may work complementarily
Medications opens
up person’s mind to CBT vs. CBT opens up person to taking medication more regularly
Affective Disorders
- Encompass Major Depressive Disorder (MDD) and Bipolar Disorder
- High recurrence: Recurs in 50% of cases and 90% after 3 or more episode
- MDD lifetime prevalence: 6-20% (16.5% according to the NIMH)
- MDD 12-month prevalence: 6.7% (30.4% of these cases are severe)
- MDD usually doesn’t last longer than 2 years but chronic course can happen in 17% of cases
- Somewhat more common in women than men
Phenotype of affective disorders
- No longer responds to surrounding but persists in a state of low mood or inability to feel joy (“anhedonia”)
- Mood
- Sleep (too much or too little)
- Weight/appetite (might eat too much or not enough, lose or gain weight)
- Self-esteem (sense of worthlessness, guilt)
- Depressive episodes can come and go but major depression only diagnosed when symptoms have been present for 2 weeks
Monoamine hypothesis of mood disorders
- Disruption in monoamine systems (serotonin and NE)
- Disfunction can happen a multiple possible levels: synthesis, release, reuptake, breakdown, receptors, 2nd messenger systems
- Accidentally discovered when blood pressure medication (for people with high blood pressure) targeting norepinephrine (which constricts blood vessels) caused depression