Question

Which of the following best describes the dopamine hypothesis of schizophrenia?

• A. Excess dopamine activity in the mesolimbic pathway leads to positive symptoms
• B. Reduced dopamine in the nigrostriatal pathway leads to cognitive symptoms
• C. Excess serotonin activity causes hallucinations
• D. Dopamine deficiency in the mesolimbic pathway leads to delusions

Hint:

The dopamine hypothesis is the classic explanation for schizophrenia. It says that the symptoms of this disorder are linked to abnormal dopamine signalling in specific nerve pathways of the brain.

Answer 1

The Correct Option is A

Concept:
The dopamine hypothesis is the classic explanation for schizophrenia. It says that the symptoms of this disorder are linked to abnormal dopamine signalling in specific nerve pathways of the brain. To answer this, you need to remember which pathway is tied to which type of symptom.

Step 1: Schizophrenia has two broad groups of symptoms. The "positive" symptoms are the added, abnormal experiences such as hallucinations, delusions and disordered thinking. The "negative" symptoms are the lost or reduced functions such as flat emotions and social withdrawal.

Step 2: The core idea of the dopamine hypothesis is that there is too much dopamine activity (overactivity) in the mesolimbic pathway of the brain, and this excess dopamine drives the positive symptoms like hallucinations and delusions. This is also why dopamine-blocking antipsychotic drugs help reduce these symptoms.

Step 3: The other options are wrong because the hypothesis is about excess (not deficiency) of dopamine for positive symptoms, it centres on dopamine rather than serotonin, and the mesolimbic overactivity link is the one that is firmly established.

Answer: Option (1) — Excess dopamine activity in the mesolimbic pathway leads to positive symptoms.