Problem
• Depression is a condition in which sufferers may feel low mood, lack of motivation and sleep. It is caused by a lack of serotonin in the synaptic cleft of neurone pathways. Serotonin is a neurotransmitter.
• Describe how serotonin acts as a neurotransmitter. Using your understanding of synaptic transmission, explain how communication between neurones in serotonin pathways of the brain would be affected in someone with depression.