lecture 21 Flashcards
Schizophrenia is a mental disorder that is characterized by what
ial withdrawal, disorganized thinking, abnormal speech, and an inability to understand reality
Schizophrenia impacts how many people
It afflicts approximately 1% of world’s population. Symptoms typically come on gradually, begin in young adulthood, and in many cases never resolve (although 20% of people eventually do quite well). About 30-50% of people with schizophrenia do not believe they have an illness or comply with their recommended treatment
Schizophrenia literally means what
split mind, but it does not imply a split personality or multiple personality.
The symptoms of schizophrenia are often grouped into 3 categories:
Negative:
Cognitive:
Positive:
what are negative symptoms of Schizophrenia
the absence of behaviours - social withdrawal, reduced emotional expression, poverty of speech, and reduced motivation
what are cognitive symptoms of Schizophrenia
disorganized and irrational thinking, deficits in learning and memory, poor abstract thinking, and poor problem solving
what are positive symptoms of Schizophrenia
the presence of delusions (typically delusions of persecution, grandeur, or control - beliefs that contradict reality) and hallucinations (perception of stimuli that are not actually present)
what symptoms emerge first (Schizophrenia)
Negative symptoms typically emerge first, followed by cognitive symptoms and, years later, by positive symptoms
Many patients with schizophrenia also exhibit neurological symptoms, such as what
poor control of eye movements and unusual facial expressions, and the illness is associated with subtle differences in
brain structure.
The causes of schizophrenia include what
environmental and genetic factors
Estimates of the heritability of schizophrenia is….
around 80%. Heritability measures the fraction of phenotype variability that can be attributed to genetic variation.
Risk of developing schizophrenia if…
your sibling has it is ~8%
– one of your parents has it is ~13%
– both of you parents have it (or an identical twin has it) is ~50%
about what % of cases are attributed to rare gene copy number variations (schizophrenia)
Around 5% of cases are attributed to rare gene copy number variations (duplicated or missing genes), which are frequently comorbid with autism and intellectual disabilities
The causes of schizophrenia include environmental and genetic factors.
Environmental factors:
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
Some evidence suggests that the concordance rate for schizophrenia is much higher for monochorionic twins and than in dichorionic twins, which suggests what
prenatal environment is an important factor
Evidence indicates that incidence of schizophrenia is related to several environmental factors that could affect development in utero:
season of birth, viral epidemics, population density, and substance abuse
what is The seasonality effect:
a disproportionately large number of schizophrenic patients are born in February, March, April, and May
The number of schizophrenic births in late winter and early spring is especially high if the temperature was _____ than normal during previous autumn
lower
The number of schizophrenic births in late winter and early spring is especially high if the temperature was lower than normal during previous autumn
WHY IS THIS
This condition keeps people indoors and favors transmission of viral illnesses
higher change of getting schizophrenia if you live in rural or urban areas?
Schizophrenia is also about three times more prevalent in people who live in the middle of large cities as compared to those who live in rural areas
– This result suggests transmission of infectious illnesses is facilitated by increased population density
how does vitamin d play a role in the likelihood of getting schizophrenia
Although cold weather and crowding may contribute to seasonality effect by increasing likelihood of infectious illness, another variable may also play role: vitamin D deficiency
• Northern European researchers have observed threefold increase in incidence of schizophrenia in immigrants and children of immigrants—especially in dark-skinned people who moved up north
• Another environmental risk factor for development of schizophrenia is parental smoking
when do symptoms of schizophrenia start
Symptoms of schizophrenia are not normally seen in childhood, however behavioral and anatomical evidence indicates that abnormal prenatal development is associated with schizophrenia
what are some Behavioural symptoms of children who go on to develop schizophrenia
Children who go on to develop schizophrenia display less sociability and deficient psychomotor functioning as kids.
what are some Anatomical symptoms of children who go on to develop schizophrenia
Minor physical abnormalities are often seen in children who go on to develop schizophrenia, such as partial webbing of the two middle toes and a high- steepled palate.
Many studies have found evidence of______ in CT and MRI scans of schizophrenic patients
loss of brain tissue
is Schizophrenia a neurodegenerative disease
Schizophrenia is not a neurodegenerative disease
The main treatment of schizophrenia is what
antipsychotic medication, often in combination with psychological and social supports
what is The Dopamine Hypothesis
excessive dopamine D2 receptor activity, particularly in the nucleus accumbens (striatum), underlies the positive symptoms of schizophrenia.
Many drugs have been developed that relieve the positive symptoms of schizophrenia. They are called antipsychotics or neuroleptics and they all block dopamine D2 receptors.
• In contrast, dopamine receptor agonists, like crystal meth and cocaine, tend to temporarily elicit certain aspects of the positive symptoms of schizophrenia in people who do not have the disorder.
positive symptoms of schizophrenia can often be managed with what
dopamine D2 receptor antagonists
Although the positive symptoms of schizophrenia can often be managed with dopamine D2 receptor antagonists, these drugs do not significantly reduce what
the negative symptoms of the disease
Some evidence suggests that the negative symptoms of schizophrenia result from what
abnormal brain activity in the prefrontal cortex.
Some evidence suggests that the negative symptoms of schizophrenia result from abnormal brain activity in the prefrontal cortex.
– For example, the negative symptoms of schizophrenia are similar to those produced by damage where
to the prefrontal cortex, and schizophrenic patients do poorly on neuropsychological tests that are sensitive to prefrontal damage
In general, the negative symptoms of schizophrenia may be caused by what
hypofrontality
what is hypofrontality
decreased activity of the frontal lobes, particularly the dorsolateral prefrontal cortex, which may relate to hypoactivity of D1 receptor activity in this area
While excess dopamine signaling in the striatum has been associated with the positive symptoms of schizophrenia, reduced dopamine signaling in the prefrontal cortex has been associated with what
the negative symptoms
is it possible that schizophrenics have too little dopamine in the prefrontal cortex and too much elsewhere.
yes
The atypical antipsychotic clozapine has been found (in monkeys) to do what
simultaneously decrease dopamine levels in the striatum and increase dopamine levels in the prefrontal cortex
what are Atypical antipsychotic medications
Recently developed medications which aim to reduce both the positive symptoms and negative symptoms of schizophrenia. They typically influence the activity of several neurotransmitter receptors (beyond blocking the dopamine D2 receptor).
what is Clozapine
First of the atypical antipsychotic medications. It blocks both dopamine D2 and serotonin 2A receptors