What is the primary effect of MDMA on the central nervous system (CNS)?

The primary effect of MDMA on the central nervous system (CNS) is euphoria. MDMA, also known as "Ecstasy" or "Molly," is a psychoactive drug that enhances mood and emotional well-being. It works primarily by increasing the release of serotonin, a neurotransmitter associated with feelings of happiness and emotional bonding, which contributes to the euphoric effects experienced by users.

In contrast to depression and physical fatigue, which can occur during the comedown phase after the drug's effects wear off, the immediate effects of MDMA are characterized by heightened feelings of pleasure, empathy, and sociability. The drug can also cause distortions in sensory perception and increased energy levels, which align with its stimulant properties.

The other choices either describe effects that are not primary or do not accurately reflect the typical experience associated with MDMA use. Increased alertness may occur but is not specific to MDMA and is more characteristic of traditional stimulants. Analgesia, or pain relief, is not a primary effect of MDMA and is more commonly associated with different classes of drugs. Thus, euphoria stands out as the most significant and defining effect of MDMA on the CNS.