A study using MCPP to alter serotonin showed OCD symptoms increased after administration in OCD patients; this supports the role of which neurotransmitter?

A study using MCPP to alter serotonin showed OCD symptoms increased after administration in OCD patients; this supports the role of which neurotransmitter?

• A. Dopamine
• B. Serotonin
• C. GABA
• D. Acetylcholine

Answer: (B)

This question tests how a pharmacological challenge can reveal which neurotransmitter system is involved in OCD. MCPP acts as a serotonin receptor agonist, increasing serotonin activity. If OCD symptoms worsen after administration in patients with OCD, it suggests that the serotonin system plays a role in the disorder—the manipulation that boosts serotonin worsens the symptoms, so serotonin is implicated in OCD pathology. This aligns with clinical treatments for OCD that aim to increase serotonin levels, such as SSRIs, which improve symptoms for many patients. The result specifically points to serotonin because the drug used targets serotonin receptors; the other neurotransmitters aren’t implicated by this particular manipulation, so they’re not the primary basis for the observed change in symptoms.

This question tests how a pharmacological challenge can reveal which neurotransmitter system is involved in OCD. MCPP acts as a serotonin receptor agonist, increasing serotonin activity. If OCD symptoms worsen after administration in patients with OCD, it suggests that the serotonin system plays a role in the disorder—the manipulation that boosts serotonin worsens the symptoms, so serotonin is implicated in OCD pathology. This aligns with clinical treatments for OCD that aim to increase serotonin levels, such as SSRIs, which improve symptoms for many patients. The result specifically points to serotonin because the drug used targets serotonin receptors; the other neurotransmitters aren’t implicated by this particular manipulation, so they’re not the primary basis for the observed change in symptoms.