Schizophrenia: Symptoms, Diagnosis, and Impact

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Questions and Answers

Which of the following is the MOST accurate characterization of schizophrenia?

  • A heterogeneous clinical syndrome involving positive, negative, and cognitive symptoms. (correct)
  • A condition primarily defined by hallucinations and delusions.
  • A rare disorder mainly affecting elderly individuals.
  • A singular condition with uniform symptoms.

Which of the following is an example of a 'negative symptom' in schizophrenia?

  • Auditory hallucinations.
  • Delusions of grandeur.
  • Disorganized speech.
  • Affective flattening. (correct)

According to the DSM-5 criteria, what is the minimum duration of continuous signs of disturbance required for a schizophrenia diagnosis?

  • 6 months. (correct)
  • 1 month.
  • 12 months.
  • 3 months.

A patient presents with disorganized thinking, tangential speech, and difficulty maintaining a coherent conversation. Which type of symptom is the patient MOST likely exhibiting?

<p>Formal thought disorder. (B)</p> Signup and view all the answers

What role does the mesolimbic dopamine pathway play in schizophrenia?

<p>It is associated with positive symptoms, such as delusions and hallucinations, due to dysfunction. (B)</p> Signup and view all the answers

What is the primary mechanism of action of traditional antipsychotic drugs in treating schizophrenia?

<p>Blocking dopamine receptors. (A)</p> Signup and view all the answers

Which prenatal factor has been associated with an increased risk of schizophrenia in offspring?

<p>Paternal age over 50 at birth. (C)</p> Signup and view all the answers

How do atypical antipsychotics differ from typical antipsychotics in the treatment of schizophrenia?

<p>Atypical antipsychotics have a reduced tendency to cause movement disorders compared to typical antipsychotics. (A)</p> Signup and view all the answers

What is the MOST likely explanation for how glutamate dysfunction is related to schizophrenia?

<p>Glutamate hypofunction may account for both the upregulation of the mesolimbic dopamine system and downregulation of the mesocortical system. (A)</p> Signup and view all the answers

Which of the following factors is associated with increased severity or poorer prognosis in individuals with schizophrenia?

<p>Childhood trauma or CNS infections. (D)</p> Signup and view all the answers

Flashcards

Schizophrenia

A heterogeneous clinical syndrome with positive, negative, and cognitive symptoms.

Delusions

False beliefs strongly held despite contradictory evidence.

Hallucinations

Sensory perceptions in the absence of external stimuli (e.g., auditory hallucinations).

Disorganized Behavior

Chaotic, unpredictable, or inappropriate behavior.

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Affective Flattening

Reduced or absent emotional expression.

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Anhedonia

Inability to experience pleasure.

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Apparent Apathy

Lack of motivation or interest in activities.

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Dopamine Hypothesis (basic model)

Excess activity in the mesolimbic dopamine pathway.

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Antipsychotics

Block dopamine receptors (D2, D3, D4).

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Etiology of Schizophrenia

The cause of Schizophrenia in unknown but both biological and environmental factors play a role.

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Study Notes

  • Schizophrenia is a heterogeneous clinical syndrome characterized by a constellation of symptoms classified into positive, negative, and cognitive dysfunction domains

Prevalence and Impact

  • Schizophrenia affects the prefrontal cortex, impacting decision-making
  • Lifetime prevalence is 0.4% (previously 1%)
  • Annual incidence ranges from 8-43 new cases per 100,000 population
  • Schizophrenia ranks among the top 10 leading causes of disability worldwide
  • More common in men, especially early in life; in women, it often manifests later
  • Diagnosis relies on DSM-V criteria, as there is no specific diagnostic test
  • MRI scans can be used to assess brain function

Symptoms

  • Schizophrenia is a psychotic disorder marked by impaired reality perception
  • Positive symptoms involve abnormal behaviors, like delusions (false beliefs despite evidence), hallucinations (sensory perceptions without external stimuli, commonly auditory), disorganized behavior (chaotic, unpredictable actions), and formal thought disorder (disorganized thinking)
  • Negative symptoms involve decreased normal behavior. These symptoms include affective flattening (reduced emotional expression), blunting of mood (reduced emotional intensity), anhedonia (inability to experience pleasure), apparent apathy (lack of motivation), lack of spontaneous speech/action, and disordered speech

DSM-5 Diagnostic Criteria

  • Requires two or more of the following symptoms for a significant time during a one-month period: delusions, hallucinations, disorganized speech, grossly disorganized or catatonic behavior, or negative symptoms (at least one of the above)
  • Decreased level of function in major areas (work, interpersonal relations, self-care)
  • Continuous signs of disturbance for at least six months, including one month of symptoms meeting criterion A
  • Rule out other disorders
  • Rule out other causes

Etiology

  • The cause of schizophrenia is unknown, involves both biological and environmental factors
  • First-degree relatives of individuals with schizophrenia have an increased risk
  • GWAS studies confirm a genetic basis, involving genes related to inflammation and myelination
  • Prenatal factors, such as issues during neural system development and advanced paternal age (>50 years), perinatal factors, like obstetric complications and postnatal factors include low birth weight
  • Childhood trauma/CNS infections increase risk
  • Cannabis use disorder is associated with increased schizophrenia risk, rising from 3.7% to 10.3% post-legalization

Pathophysiology

  • Mesolimbic dopamine system dysfunction is linked to positive symptoms like delusions and hallucinations due to its role in reward processing and emotional responses
  • Mesocortical dopamine system dysfunction, involved in cognitive functions (executive function, working memory), linked to negative symptoms and cognitive deficits
  • The dopamine hypothesis suggests excess activity in the mesolimbic dopamine pathway mediates positive symptoms, while decreased dopamine in the prefrontal cortex mediates negative and cognitive symptoms of schizophrenia
  • The revised model considers GABA, serotonin, glutamate dysfunction, and inflammation and glutamate receptors hypofunction may upregulate the mesolimbic dopamine system and downregulate the mesocortical system
  • The neurodevelopmental theory posits that neurons fail to migrate correctly, make inappropriate connections, and undergo apoptosis
  • Structural brain imaging studies show enlarged lateral and third ventricles alongside decreased volume in the medial temporal lobe
  • Imbalance of dopamine

Treatment

  • Antipsychotics (or neuroleptics) block dopamine receptors (D1-D5 subtypes) to control symptoms and require maintenance treatment for many years
  • D2, D3, and D4 receptors in the limbic system are targeted
  • Targeting D2 receptors reduces positive symptoms but can decrease dopamine in the basal ganglia, causing parkinsonism, and may worsen negative symptoms
  • D3 and D4 are mainly in limbic areas, while D1 is found everywhere
  • Relapses are common, even with medication
  • Atypical drugs (e.g., clozapine, risperidone, olanzapine, quetiapine, aripiprazole) have a reduced tendency to cause movement disorders and act on serotonin receptors, helping to balance dopamine activity

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