Which of the following is responsible for the mood changes/depression in humans?
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → Noradrenaline
Noradrenaline is one of the neurotransmitters that plays a role in mood changes. If its level is low, the signal-sending activity becomes low and the person suffers from depression. Antidepressant drugs (such as iproniazid and phenelzine) inhibit the enzymes that break down noradrenaline.
Note: This question is from the pre-rationalised NCERT book (2022-23). The topic is not there in the latest NCERT book (2026-27), and it is also out of the CUET 2026 syllabus.
NCERT (Pre-rationalised edition, 2022-23):
Neurologically Active Drugs – …
