Mental disorders Flashcards
Why can’t we assume that mental disorders are discrete/unitary diseases
-too much heterogeneity within diagnostic categories (ex: 2 ppl with the same disorder can have totally different symptoms)
-too much comorbidity across categories (being diagnosed with more than one mental disorders)
-continuity with normality (because of healthy normal groups variance, it is hard to establish “diagnostic lines”)
Why do gene variants that increase the risk of developing a psychiatric illness persist in the population? Why haven’t they been selected out?
Many of the gene variants associated with increased risk of mental illness regulate brain development and neural plasticity.
(neuronal migration in vitro, rules of plasticity, learning, memory, etc etc)
Their expression in the brain gives rise to altered patterns of neural activity throughout the brain. The problematic protein variants slightly alter the dynamic interactions of the thousands of proteins expressed in the brain across different cell types during development and maturation.
What are the components of the theory explaining the persistence of the genes that cause mental disorders? (explain)
Mutation-selection balance
→ mental disorder susceptibility genes are continually being selected out through evolution. But NEW mutation keep arising.
Inherited gene mutations
→mutations stick around for a long time. Brain is robust, allowing genetic variations to accumulate in the population if the individual mutations are not too severe
How do bad gene mutations affect the brain?
Do not directly cause a disease…they can collectively compromise the evolved interactions of everything in the brain, reducing the overall robustness of brain development and function
Why can identical twins have so much brain differences even if they have the same dna?
unavoidable randomness at the molecular level→ impacts how the brain develops
ex: main avec plein de crayons de couleur
What can body symmetry tell us about brain development?
Indicative of robustness of the genetic instructions
… clearer instructions
What does not correlate with body symmetry?
a. intelligence
b. physical health
c. physical attractiveness
d. symptom expression in schizophrenia
d.
What are the advices to maintain a healthy brain
Same as healthy body…(stay active, nutrition, stress and blood pressure reduction, good sleep habits, limit alcohol and avoid tobacco/drugs)
Define schizophrenia
Mental disorder characterized social withdrawal, disorganized thinking, abnormal speech, and an inability to understandreality.
Compare the different types of schizophrenia symptoms
Negative: the absence of behaviors (lost)
→ex: social withdrawal, reduced emotional expression, poverty of speech, and reduced motivation
Typically emerge 1st…then cognitive…then positive
Cognitive: disorganized and irrational thinking, deficits in learning and memory, poor abstract thinking, and poor problem solving
Positive: the presence of behaviors (not here before) →ex: delusions of persecution/grandeur/control, hallucinations
[Neurological: for example poor control of eye movements and unusual facial expressions]
How can we explain the high percentages of schizophrenia cases in male early adulthood vs female menopause?
Seemingly a correlation with hormone signaling.
In men, period associated with the end of myelination.(occipital–prefrontal btw)
How can we explain the high percentages of schizophrenia cases in male early adulthood vs female menopause?
Seemingly a correlation with hormone signaling.
In men, period associated with the end of myelination.(occipital–prefrontal btw)
→hypothesis: born with schizophrenia, reveals itself when myelination ends
→other one: pruning is too aggressive, too much synapses are destroyed
What is synaptic pruning?
Between early childhood and adulthood, elimination of useless synapses.
Name some believed environmental factors contributing to schizophrenia
mother’s nutrition during pregnancy
mother’s stress during pregnancy
certain infections (particularly during pregnancy)
birth month
being raised in a city
childhood trauma
social isolation
perinatal hypoxia / brain damage
What is the cause of schizophrenia?
environmental and genetic factors
What does heritability measure?
The fraction of phenotype variability that can be attributed to genetic variation
The amount of variation attributed to genetics→ the amount of variation that would be eliminated if everyone had the same genes.
(but even if no genetic variability, there is still the impact of environment )
How does the risk of developing schizo varies as we get further away from family bonds..
both parents 50%…one 13%…sibling 8%
Which factor, frequently comorbid with autism and intellectual disabilities, is an alleged cause of schizophrenia
rare gene copy number variations (duplicated or missing genes)..around 5% of cases are attributed to this
What is the seasonality effect?
A disproportionately large number of schizophrenic patients being born in February, March, April, and May
→suggests that something is happening in the womb few months earlier (ex: colder, ppl go inside and are more likely to get infections)
Name some factors affecting development in utero and leading to schizophrenia.
Season of birth, viral epidemics, population density, parental smoking
→Higher number of schizophrenic births in late winter and early spring if the temperature was lower than normal during previous autumn (keeps people indoors and favors transmission of viral illnesses)
→Three times more prevalent large cities >rural areas (transmission of infectious illnesses is facilitated by increased population density)
Monochorionic vs dichorionic twins
share one placenta vs individual placenta (identical twins either way)
How can prenatal environments of identical twins affect schizophrenia rates
Prenatal environments of monochorionic twins + similar than di
Concordance rate for schizophrenia ↑ for monochorionic twins
Name the behavioral and anatomical evidence indicating that abnormal prenatal development is associated with schizophrenia
Behavioral: Children who go on to develop schizophrenia display less sociability and deficient psychomotor functioning as kids.
Anatomical: Minor physical abnormalities are often seen in children who go on to develop schizophrenia →ex: partial webbing of the two middle toes and a high-steepled palate.
What is the main treatment for schizophrenia
Medication, often combined with psychological and social supports
