Anxiety Disorders Flashcards
Biopsychosocial Approach To Understanding Health
Combination of…
Biology e.g. gender, disability
Psychology e.g. personality, past trauma, beliefs
Social context e.g. family background, socioeconomic status, education
Anxiety Disorder
Anxiety interferes with day-to-day functioning
Physiological symptoms: hypertension, nausea, sleep disturbances
Lifetime prevalence: 17%
Female : male ratio - 2 : 1
Panic Disorder
Frequent panic attacks, feeling of impending doom
OCD
Obsessions cause anxiety/distress
Compulsions serve to neutralise anxiety
Generalised Anxiety Disorder
6 months of persistent excessive anxiety
Specific Phobias
Clinically significant anxiety provoked by exposure to a feared object - leads to avoidance behaviour
Genetic contribution to anxiety disorders
Evidence of genetic contribution but no specific genes have been linked
Amygdala and the fear response
Critical in fear response
Sensory info from the thalamus and cortex processed in basolateral nucleus of amygdala
Passed on to central nucleus
Activates HPA-axis
HPA-axis
Increased stress response
H ypothalamus - releases corticotropin-release hormone (CRH)
P ituary Gland - releases adrenocorticotropic hormone (ACTH)
A drenal Gland - releases cortisol which leads to increased sympathetic activation
Hippocampus and Stress
Glucocorticoid receptors in hippocampus measure cortisol levels
When levels are too high the hippocampus inhibits CRH release in hypothalamus - inhibition of HRA-axis activation
Amygdala and Anxiety
Over-activated in patients with anxiety disorder
Hippocampul Volume in Anxiety Disorders and PTSD
Reduced hippocampul volume
Reduced number of gluco-corticoid receptors
War Veterans with PTSD - show decreased hippocampul volume
Stress/Stressors
Stress-reaction to harm or threat
Stressors-stimuli that cause stress
Short-Term Stress
Stress is adaptive - acute stressors improve immune function
Long-Term Stress
Stress is maladaptive - chronic stressors impair immune function
Learned Emotional Responses
- Classical fear conditioning e.g. Little Albert, 1919
2. Social referencing/imitation - seeing others emotional response leads to avoidance of previously neutral stimuli
Amygdala and Fear Conditioning
Lesions of the Amygdala block fear conditioning
Amydgala receives input from all sensory systems-appears responsible for adding emotional significance to another stimuli
Lateral amygdala is the most critical in conditioned fear
Hippocampus and Contextual Fear Conditioning
e.g. rat learns link between seeing a light and receiving a shock. It also links the context - the cage it is in when receiving the shock
Ventromedial Prefrontal Cortex and Extinction
Conditioned stimulus repeatedly presented by itself
Conditioned emotional response disappears over time
Not gone forever just inhibited
vmPFC lesions-inhibition impaired
vmPFC stimulation-enhanced inhibition
Behavioural Therapy in Phobias
Over-activation of amygdala disappears after BT
Increased activity in orbito-frontal cortex after exposure therapy: cognitive control of fear response
Medial Prefrontal Cortex and Fear Conditioning
Medial PFC suppresses conditioned fear response by inhibiting lateral amygdala
Pharmacotherapy in Anxiety Disorders
Gamma-aminobutyric acid (GABA) - most effective neurotransmitter
Benzodiazepine binds GABA-ergic ion-channels
This increases inhibitory efficiency and has a similar effect to ethanol
SSRIs
Selective serotonin reuptake inhibitors
Serotonin is only indirectly involved in anxiety disorders
SSRIs increase density of glucocorticoid receptors in hippocampus - means better modulation of CRH release in hypothalamus - HPA axis less activated
