What is schizophrenia associated with?

• A. Serotonin overdose.
• B. Norepinephrine deficiency.
• C. Acetylcholine excess.
• D. Dopamine imbalance.

Answer: (D)

Schizophrenia is linked to dysregulation of dopamine signaling in brain circuits that regulate thought, motivation, and reward. The dopamine hypothesis is supported by several lines of evidence: drugs that block dopamine D2 receptors alleviate positive symptoms, while agents that increase dopamine can worsen or precipitate psychosis; neuroimaging shows altered dopaminergic activity, especially increased dopamine synthesis and release in striatal regions and disrupted dopamine function in the prefrontal cortex. This imbalance helps explain why there are positive symptoms (like hallucinations) from excess dopamine in mesolimbic pathways and negative/cognitive symptoms from reduced dopamine in mesocortical pathways. Other neurotransmitters (glutamate, GABA, serotonin) also play roles, but dopamine imbalance is the best-supported association. So the correct concept is that schizophrenia is tied to dopaminergic dysregulation, not serotonin overdose, norepinephrine deficiency, or acetylcholine excess.