Depression has been linked to low activity of __________.

Answer & explanation

Correct answer: option 2

The correct answer is Option (2) → Serotonin

Option (1) Dopamine — Incorrect. Excess activity of dopamine is linked to schizophrenia, not low activity to depression.

Option (2) Serotonin — Correct. Depression has been linked to low activity of serotonin.

Option (3) Gamma aminobutyric acid — Incorrect. Low activity of GABA is linked to anxiety disorders.

Option (4) Endorphins — Incorrect. Endorphins are the body’s own pain-relieving chemicals, released for example during hard exercise or pain. They are not the chemical linked to depression.

Note: The term in Option (4), ‘endorphins’, is not in the pre-rationalised NCERT, which NTA followed in 2023, nor in the NCERT book (2025-26); it is explained here for the benefit of the students.

NCERT (2025-26): “Factors Underlying Abnormal Behaviour … a tiny space called synapse separates one neuron from the next, and the message must move across that space. When an electrical impulse reaches a neuron’s ending, the nerve ending is stimulated to release a chemical, called a neuro-transmitter. Studies indicate that abnormal activity by certain neuro-transmitters can lead to specific psychological disorders. Anxiety disorders have been linked to low activity of the neurotransmitter gamma aminobutyric acid (GABA), schizophrenia to excess activity of dopamine, and depression to low activity of serotonin.…”