Brain Structure and Psychosis Overview

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Questions and Answers

What type of symptoms are characterized by the loss of social engagement in psychosis?

Negative symptoms (correct)

Affective symptoms

Positive symptoms

Cognitive symptoms

Which dopaminergic pathway is responsible for regulating pleasure and emotion?

Mesolimbic pathway (correct)

Nigrostriatal pathway

Mesocortical pathway

Tuberoinfundibular pathway

What is a significant risk factor contributing to the development of psychosis?

Regular medication adherence

High protein diet

Increased physical activity

Childhood trauma (correct)

In treating psychosis, what effect does the inhibition of the mesocortical system typically result in?

Reduced social engagement Signup and view all the answers

What type of antipsychotic is most effective but also carries significant side effects such as sedation?

Clozapine Signup and view all the answers

Which of the following is NOT a pathway categorized within the dopaminergic system?

Corticostriatal Signup and view all the answers

What kind of side effect results in muscle spasms when using certain antipsychotics?

Acute dystonia Signup and view all the answers

What effect do first-generation antipsychotics typically have on cognitive and negative symptoms?

They worsen cognitive and negative symptoms Signup and view all the answers

What is the recommended practice concerning polypharmacy in psychosis treatment?

Avoid prescribing more than one medication Signup and view all the answers

What long-term effect is generally accepted regarding antipsychotics?

Effective for treating negative symptoms Signup and view all the answers

What is the primary role of the nigrostriatal pathway in the brain?

Facilitates movement control Signup and view all the answers

Which of the following is a common consequence of using antipsychotics on the mesolimbic system?

Dysphoria and loss of pleasure Signup and view all the answers

How do second-generation antipsychotics compare to first-generation ones in terms of their effects on symptoms?

They improve cognitive and negative symptoms Signup and view all the answers

What is a significant drawback of polypharmacy in treating psychosis?

Increases the risk of adverse drug interactions Signup and view all the answers

Which neurotransmitter's activity is primarily inhibited in the mesocortical system leading to cognitive impairment?

Dopamine Signup and view all the answers

What is the genetic contribution rate in the risk factor for developing psychosis?

50% genetic and 50% environmental Signup and view all the answers

What common side effect of antipsychotics is characterized by an involuntary movement disorder, particularly of the mouth and lips?

Tardive dyskinesia Signup and view all the answers

What is considered a beneficial outcome of early intervention in psychosis?

Reduction in the severity of symptoms Signup and view all the answers

What effect does chronic drug use have on the mesolimbic pathway associated with reward processing?

Leads to drug-induced psychosis Signup and view all the answers

Which of the following describes the concept of 'sensitization' in relation to antipsychotic medication?

Increased responsiveness to dopamine due to treatment Signup and view all the answers

What is the primary function of the tuberoinfundibular pathway?

Regulates the endocrine system Signup and view all the answers

What role does dopamine play in the mesolimbic system?

Enhancement of pleasure and threat evaluation Signup and view all the answers

What consequence do antipsychotics typically have on the mesocortical system?

Worsening of cognitive impairment Signup and view all the answers

How do second-generation antipsychotics primarily differ from first-generation antipsychotics?

They are less sedating and cause fewer movement problems Signup and view all the answers

What effect does prolonged untreated psychosis (DUP) generally have on patient outcomes?

Worsening of cognitive functions Signup and view all the answers

What is a common long-term effect of antipsychotic treatment?

Support for sustained maintenance Signup and view all the answers

Which condition is characterized by an involuntary movement disorder caused by antipsychotic medication?

Tardive dyskinesia Signup and view all the answers

What is a significant challenge in predictive psychopharmacology associated with antipsychotics?

Predicting individual responses to drugs Signup and view all the answers

What is the consequence of dopamine blocking in areas outside the mesolimbic pathway?

Extrapyramidal side effects Signup and view all the answers

What is the role of glutamate in the context provided?

Acts as an excitatory neurotransmitter Signup and view all the answers

Study Notes

Brain Structure and Function

The brain is divided into three main parts: forebrain, midbrain, and hindbrain.
The forebrain is responsible for complex functions.
The cerebellum is involved in motor control and learning.
The brainstem handles basic functions like the release of serotonin, adrenaline, and dopamine.

Psychosis

Symptoms: Positive symptoms (new, e.g., hallucinations, delusions) and negative symptoms (lost, e.g., social withdrawal).
Risk Factors:
- Genetic predisposition (50% genetic, 50% environmental; strong heritability, polygenetic risk; 50% chance in identical twins).
- Environmental factors (obstetric complications, childhood trauma, immigration status, cannabis use).
Early Intervention: Crucial to reduce duration of untreated psychosis (DUP). Longer DUP correlates with worse outcomes.
Neurotransmitter Imbalance: Glutamate ("go") and GABA ("stop") are implicated. Dopamine plays a significant role.

Dopaminergic Pathways

There are four main dopaminergic pathways: mesolimbic, mesocortical, nigrostriatal, and tuberinfundibular.
These pathways are distinguished by their origin and termination points.
Five types of dopamine receptors (D1, D2, etc.) exist.

Mesolimbic Pathway

This pathway regulates the limbic system, associated with emotions (fear response) and reward processing (pleasure).
Salient (threat) evaluation is also regulated.
Psychosis can involve hyperactivity in the salience component.
Drug abuse targets the reward system, causing feelings of pleasure; chronic use disrupts salience and can lead to drug-induced psychosis.

Mesocortical Pathway

This pathway regulates the prefrontal cortex (PFC), involved in cognition, motivation, and social behaviors.
Dysfunction (hypoactivity) results in negative symptoms of psychosis like cognitive impairment and social withdrawal.

Nigrostriatal Pathway

This pathway is involved in movement control via the basal ganglia.
Antipsychotics can disrupt this pathway leading to movement difficulties.

Tuberinfundibular Pathway

This pathway regulates the hypothalamic-pituitary-adrenal (HPA) axis, which controls hormone regulation.
Antipsychotics can disrupt this, potentially causing hormonal imbalances.

Antipsychotics

Mechanism of Action: They modulate the dopaminergic system, specifically targeting D2 receptors as postsynaptic dopamine antagonists.
Dosage: Ideally bind to 60-70% of dopamine receptors.
Effects on Mesolimbic Pathway: Suppressing pleasure/threat evaluation can cause dysphoria (lack of pleasure).
Effects on Mesocortical Pathway: Further suppression can worsen negative symptoms (the positive symptom benefits might be counter-balanced).
Generations: First-generation antipsychotics worsened negative/cognitive symptoms. Second-generation antipsychotics showed improvements in these areas without causing movement problems.

Clozapine

Clozapine is a very effective second-generation antipsychotic.
It carries intense side effects (sedation, drooling), requiring regular blood monitoring.
Used as a last resort after failing two other antipsychotics.
Predictive psychopharmacology is impossible; what works for one patient does not guarantee success for another.

Long-Term Antipsychotic Effects

Positive symptom control is established, but long-term effects are not extensively proven in the research.
Some individuals may never fully recover without medication, suggesting lasting impact of the disorder.
Efficacy of long-term maintenance is well-documented.
Antipsychotic use does not appear to directly change the brain structure.
Dopamine cell "sensitization" is possible, by increased response over time.

Polypharmacy

Multiple medications are often used, potentially increasing the risk for treatment-resistant psychosis.
Polypharmacy is controversial in practice; one medication at a time is preferred.

Side Effects

Dopamine Blocking: While blocking dopamine in mesolimbic pathway is desirable, it can cause side effects in other brain areas.
Extrapyramidal Side Effects:
- Acute dystonia – muscle spasms.
- Akathisia – inner restlessness.
- Parkinsonism – movement stiffness.
- Tardive dyskinesia – abnormal mouth/lip movements.
Cardiometabolic Side Effects (with second-gen):
- Increased risk of obesity/diabetes/cardiovascular disease as a result of effects on hypothalamus, lipids, and glucose/insulin regulation.

Mortality

Psychosis can reduce lifespan by 15-20 years.

Future Research

Refining population-based strategies.
Developing drugs with reduced side effects.
Encouraging adherence to treatment.
Creating new medications.
Investigating acetylcholine (as in dementia) and glutamatergic drugs.

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Description

Explore the intricate workings of brain structure and its connection to psychosis. This quiz covers the main parts of the brain, key symptoms of psychosis, and factors influencing its development. Understanding these components is essential for early intervention and better outcomes.