Low activity of serotonin has been found to be highly associated with:

Answer & explanation

Correct answer: option 2

The correct answer is Option (2) → Depression

A neuro-transmitter is the chemical a nerve ending releases to carry a message across the synapse. Abnormal activity of certain neuro-transmitters can lead to specific psychological disorders.

Option (1) Anxiety — Incorrect. Anxiety disorders have been linked to low activity of GABA (gamma aminobutyric acid), not of serotonin.

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

Option (3) Schizophrenia — Incorrect. Schizophrenia has been linked to excess activity of dopamine, a different neuro-transmitter and the opposite direction (excess, not low).

Option (4) Attention Deficit Hyperactive Disorder (ADHD) — Incorrect. ADHD is a neurodevelopmental disorder whose main features are inattention and hyperactivity-impulsivity. No neuro-transmitter is linked to it in the findings described, and serotonin is linked to depression.

Note: A similar question was also asked in CUET (UG) 2023 on 18-06-2023 (Slot 2).

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.…”