Which of the following has the lowest risk for sexual dysfunction and weight gain?

A. Mesolimbic pathway is associated with reward, motivation, and emotions and is hyperactive in schizophrenia, leading to positive symptoms such as hallucinations, delusions, and disorganized thinking. Antipsychotic medications work by blocking dopamine (D2) receptors in this pathway, reducing psychotic symptoms.

B. Nigrostriatal pathway controls motor function and coordination. Dopamine blockade in this pathway leads to extrapyramidal symptoms (EPS) such as tremors, rigidity, and tardive dyskinesia, which are common side effects of first-generation antipsychotics (typical antipsychotics).

C. Tuberoinfundibular pathway regulates prolactin secretion. Dopamine inhibits prolactin release, so blocking D2 receptors with antipsychotics leads to increased prolactin levels, causing gynecomastia, galactorrhea, and menstrual irregularities.

D. Mesocortical pathway is responsible for cognition, motivation, and emotional regulation. In schizophrenia, this pathway is hypoactive, contributing to negative symptoms such as apathy, social withdrawal, and cognitive impairment.

A. Dopamine. Tourette’s syndrome is primarily associated with dopamine dysregulation, particularly increased dopamine activity in the basal ganglia. This overactivity leads to excessive, involuntary motor and vocal tics. Dopamine-blocking medications, such as antipsychotics (e.g., haloperidol, risperidone), can help reduce tic severity.

B. Serotonin. While serotonin plays a role in mood regulation and impulse control, it is not the primary neurotransmitter involved in Tourette’s. However, selective serotonin reuptake inhibitors (SSRIs) may be used to treat co-occurring obsessive-compulsive disorder (OCD) and anxiety symptoms in Tourette’s patients.

C. Glutamate is the brain’s primary excitatory neurotransmitter, involved in learning and memory. While some research suggests glutamate imbalances may contribute to tic severity and compulsive behaviors, dopamine remains the key neurotransmitter in Tourette’s pathology.

D. GABA is the brain’s primary inhibitory neurotransmitter, responsible for reducing neural excitability. Though impaired GABAergic inhibition may contribute to tic generation, the main abnormality in Tourette’s involves dopamine overactivity in the basal ganglia and cortico-striatal-thalamo-cortical circuits.