Which statement correctly differentiates SSRIs from SNRIs in terms of reuptake inhibition?

• A. SSRIs block serotonin reuptake; SNRIs block both serotonin and norepinephrine reuptake.
• B. SSIs block norepinephrine reuptake; SNRIs block serotonin reuptake.
• C. SSRIS inhibit GABA; SNRIs inhibit glutamate.
• D. They have identical mechanisms.

Answer: (A)

The key idea is transporter selectivity in reuptake inhibition. SSRIs specifically block the serotonin transporter (SERT), which increases serotonin levels in the synaptic cleft. SNRIs block both the serotonin transporter and the norepinephrine transporter (NET), raising levels of both serotonin and norepinephrine. That’s why the statement that SSRIs block serotonin reuptake while SNRIs block both serotonin and norepinephrine reuptake is the correct distinction.

This difference in target explains their different clinical profiles: SSRIs mainly modulate serotonin, while SNRIs add norepinephrine effects, which can influence mood and pain pathways. The other statements don’t fit because they either misstate which transporter is inhibited, mention unrelated neurotransmitters (GABA/glutamate), or claim identical mechanisms.