Final answer:
Dopamine is the neurotransmitter found in increased amounts in the brain of someone with schizophrenia. It contributes to the positive symptoms of the disorder, and antipsychotic medications target dopamine receptors to alleviate these symptoms. GABA, being inhibitory, is not directly implicated in the overactive symptoms of schizophrenia.
Step-by-step explanation:
The neurotransmitter you would find in increased amounts in the brain of someone with schizophrenia is dopamine. Schizophrenia has been associated with dysfunctional dopamine neurotransmission, specifically an overactivity of dopamine pathways. Current understanding supports the idea that this overactivity contributes to the positive symptoms of schizophrenia, such as hallucinations and delusions. The antipsychotic medications that are commonly used for the treatment of schizophrenia act as antagonists at dopamine receptors, primarily the D2 subtype, which blocks the effects of dopamine and can mitigate symptoms.
In contrast, gamma-Aminobutyric acid (GABA) is typically an inhibitory neurotransmitter in the brain and is not directly implicated in the overactive symptoms of schizophrenia. The imbalance involving GABA in neurological disorders often pertains to a different array of symptoms and conditions, such as anxiety, epilepsy, and in the case of Parkinson's disease, the complex interplay between dopamine, GABA, and glutamate is involved in the disease process.
Therefore, in the context of schizophrenia, the focus is on the atypical levels of dopamine rather than alterations in GABA neurotransmission.