Theoretical Models: Diathesis-Stress and Biological Flashcards
Can we really talk about “causes of abnormal behavior or psychological suffering”?
- No
- we can only talk about risk factors
- no identifiable single cause or even a set number of causes
- there are always multiple risk factors that lead to a disorder
Etiology of mental Illness: types of causal relationships
=necessary cause: if disorder y occurs, then cause x must have preceded it
-we don’t know any that fit this
=sufficient cause: if cause x occurs, then disorder y will also occur
-we don’t know any that fit this either
=contributory cause: if x occurs, then the probability of disorder y increases
-we have a lot of these
A caveat about causality
- Which way does the relationship go?
- ex does negative thinking cause depression or depression cause negative thinking?
Diathesis-Stress Model
- diathesis: underlying vulnerability
- stress: an environmental life event
- the combination of the two lead to disorder
Factors for Diathesis
- biological factors: genes, disordered biochemistry, brain abnormality
- social factors: maladaptive upbringing, chronic stress
- psychological factors: poor social skills, maladaptive thought patterns, unconscious conflicts
Triggers for Stress
- biological trigger: onset of disease, toxic exposure
- social trigger: traumatic event, major loss
- psychological trigger: perceived loss of control, violation of trust
Additive Model of Diathesis Stress
- probability of disorder increases with increasing level of stress
- but at all levels, even low levels, the probability is higher for high diathesis over medium diathesis over low diathesis
Interactive Model of Diathesis Stress
- at low levels of stress, the probability of getting the disorder is the same for low, medium, and high diathesis
- as stress levels increase, the probability of getting the disorder increases at a different rate depending on your diathesis
- it increases a lot for high diathesis, a middle amount for medium diathesis, and barely at all for low diathesis
Protective Factors
protective factors –> resilience
-ex social support –> less affected by stress
Biopsychosocial Model
-interplay of biological, psychological, and social factors
Biological Model: Neurons
- information flows through neurons
- dendrites collect signals
- cell body integrates incoming signals and sends them out
- axon sends the signal to the next cell’s dendrites
Biological Model: Neurotransmitter imbalance
- synaptic reuptake should take up any extra neurotransmitters
1. excessive production and release of NTs - ex: schizophrenia - excess dopamine
2. dysfunctions in processes of deactivation - ex: depression - too little serotonin left in synapse
3. especially sensitive or insensitive receptors - ex: anxiety - receiving/postsynaptic neuron is not sensitive enough to GABA
Most important NTs
- Acetylcholine: undersupply –> alzheimers
- dopamine: oversupply –> schizophrenia, undersupply –> parkinson’s
- serotonin: undersupply –> depression
- GABA: undersupply –> seizure, tremors, insomnia, anxiety
- glutamate: oversupply –> migraines, seizures
Biological Model: Hormonal Imbalances
=HPA axis -hypothalamic-pituitary-adrenal
=Stress activates the HPA axis
-HPA axis dysfunction leads to disorders
-body is not sensitive enough to cortisol and keeps making CRH and then more cortisol which leads to disorders
HPA axis
Hypothalamus – CRH (corticotrophin-releasing hormone) –> Pituitary Gland – ACTH (adrenocorticotrophic hormone) –> Adrenal Glands – cortisol –> to the blood stream
