Which neurotransmitter imbalance is most strongly associated with the positive symptoms of schizophrenia?

GMCH Nursing Officer-2025

Mental Health Nursing

Easy

Appeared in: GMCH Nursing Officer-2025

Explanation

The dopamine hypothesis is the most widely accepted theory for the positive symptoms of schizophrenia.
This hypothesis specifically points to hyperactivity (excessive activity) of dopamine in the mesolimbic pathway of the brain.
Positive symptoms include hallucinations, delusions, and disorganized thinking.
The effectiveness of antipsychotic drugs, which work by blocking dopamine receptors, provides strong evidence for this theory.

Option A: Decreased serotonin is primarily associated with mood disorders like depression. While serotonin plays a complex role in schizophrenia, it is not the main driver of positive symptoms.
Option C: Decreased GABA activity is observed in schizophrenia and is thought to contribute to cognitive deficits and disinhibition of the dopamine system. However, it is not the direct or primary cause of positive symptoms.
Option D: Increased norepinephrine is more characteristic of conditions involving high arousal and stress, such as anxiety disorders or the manic phase of bipolar disorder.

Visual 1: Diagram: The four major dopamine pathways in the brain (mesolimbic, mesocortical, nigrostriatal, tuberoinfundibular). The diagram should clearly label each pathway and use arrows to indicate hyperactivity in the mesolimbic pathway and hypoactivity in the mesocortical pathway in schizophrenia.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Neurobiological basis of schizophrenia as background academic context rather than a clinical decision trigger.
Understanding that positive symptoms are linked to mesolimbic dopamine hyperactivity explains why antipsychotic medications (dopamine antagonists) are the primary treatment.
Nurses must monitor for side effects caused by dopamine blockade in other pathways, such as extrapyramidal symptoms (EPS) from the nigrostriatal pathway and hyperprolactinemia from the tuberoinfundibular pathway.
This knowledge helps nurses educate patients and families about how medications work and the importance of adherence to manage symptoms.

How to Approach the Question

First, identify the key concepts in the question: 'positive symptoms' and 'schizophrenia'.
Recall the primary neurobiological theory associated with schizophrenia, which is the dopamine hypothesis.
Differentiate the roles of the different dopamine pathways. Remember that 'positive' symptoms are linked to an 'excess' or 'hyperactivity' of dopamine.
Specifically, associate the mesolimbic pathway with positive symptoms.
Evaluate each option against this core knowledge. Eliminate options related to other neurotransmitters (serotonin, GABA, norepinephrine) as they are not the primary cause, and select the option that correctly links dopamine hyperactivity in the correct pathway.

Concept Tested & Keywords

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