Which neurotransmitter imbalance is linked to schizophrenia?

• A. GABA overactivity is linked to schizophrenia.
• B. Serotonin overactivity is linked to schizophrenia.
• C. Dopamine overactivity is linked to schizophrenia.
• D. Norepinephrine deficiency is linked to schizophrenia.

Answer: (C)

The main concept is how neurotransmitter activity relates to schizophrenia, with dopamine playing the central role. The classic dopamine hypothesis links excess dopamine activity in subcortical pathways, especially the mesolimbic system, to the positive symptoms of schizophrenia like hallucinations and delusions. This is supported by evidence that antipsychotic drugs— which block dopamine D2 receptors—tend to alleviate these symptoms, and by imaging studies showing heightened dopamine activity in relevant brain regions. While other neurotransmitters like GABA, norepinephrine, and serotonin can influence the condition, the strongest and most consistent association is dopamine overactivity. The other options don’t fit this primary pattern: GABA overactivity isn’t the established link, norepinephrine deficiency isn’t a core finding, and serotonin’s role is more tied to mood disorders and to the broader pharmacology of some antipsychotics rather than a direct, primary imbalance in schizophrenia.