AM - Schizophrenia I Flashcards
What is a general description of schizophrenia? (4)
Schizophrenia is a complex psychiatric disorder involving “fragmentation of cognitive processes and personality” (Bleuler, 1908).
- Onset often occurs in adolescence.
- Manifests episodically with complex symptoms.
- Stress can be a precipitating factor for symptoms in those with a vulnerability to the illness.
How does neuronal dysfunction in schizophrenia differ from neuronal degeneration.
Schizophrenia involves neuronal dysfunction rather than degeneration, allowing for “relax periods,” suggesting potential improvement of symptoms over time.
What are positive symptoms in schizophrenia and give examples? (4)
Positive symptoms are excesses or distortions in function, such as:
- Hallucinations (often auditory, sometimes visual)
- Thought disorders
- Stereotyped behaviors
What are negative symptoms in schizophrenia and give examples? (5)
Negative symptoms are deficits or reductions, such as:
- Poverty of affect
- Cognitive impairment
- Temporal disorientation
- Social withdrawal
How do positive and negative symptoms of schizophrenia progress? (3)
- Positive symptoms often develop into negative ones.
- positive symptoms tend to fluctuate over time.
- Negative symptoms are more common in the premorbid stage (period before onset of obvious psychotic symptoms like hallucinations) compared to positive symptoms
What are possible factors of schizophrenia? (4)
- Genetics
- psychosocial
- structural brain damage
- Viral infection
What factors contribute to the causes of schizophrenia? (4)
- Medical history
- Genetics
- hormonal factors
- traumatic events.
Genetic and environmental interactions play a role in risk and manifestation.
How does genetic inheritance influence schizophrenia risk? (2)
- Higher rates of schizophrenia are seen in first-degree relatives, especially identical twins (48% concordance in monozygotic twins).
- Risk decreases with more distant relatives, suggesting partial but not exclusive genetic influence.
What is polygenicity in schizophrenia genetics?
Schizophrenia is polygenic, involving multiple genes rather than a single “schizophrenia gene,” and interacts with environmental factors, making it complex and difficult to treat.
How do epigenetics affect schizophrenia risk?
Epigenetics involve changes in gene expression due to environmental factors, influencing whether genetic risk factors contribute to the disorder.
What is a risk locus and how does it relate to schizophrenia? (3)
- A specific region in the genome associated with an increased risk of schizophrenia.
- Schizophrenia risk loci involve multiple genes that affect one or several biological pathways.
- This complexity likely contributes to the variety of symptoms observed in schizophrenia
What role does the gene DISC1 play in schizophrenia?
DISC1 (Disrupted in Schizophrenia-1) is involved in dopamine regulation, impacting mood, cognition, and behavior, which are often disrupted in schizophrenia.
How does the COMT gene impact schizophrenia risk? (5)
COMT (Catechol-O-methyltransferase) influences dopamine breakdown in the prefrontal cortex.
* Variations in COMT can alter dopamine levels, impacting susceptibility to psychotic symptoms.
* People with certain COMT variants may have different thresholds for dopamine-related disruptions, meaning:
* High-risk COMT variants increase sensitivity to environmental stressors, which may raise schizophrenia risk.
* This gene illustrates how genetic variation sets different “threshold potentials” for individuals, affecting their vulnerability to the disorder.
What is the role of Neuregulin in schizophrenia? (3)
- Neuregulin is part of a signaling protein family involved in neurodevelopment.
- Abnormal neuregulin signaling can disrupt brain development and synaptic connectivity
- Increasing vulnerability to schizophrenia.
BDNF and neuregulin both involved in cell proliferation and differentiation
