What effect does nicotine have on the body?

Nicotine is a stimulant substance that primarily affects the central nervous system. Its effects include increasing alertness and energy levels, which generally leads to disrupted sleep patterns rather than promoting restful sleep. This stimulatory action can make it more difficult for individuals to fall asleep or achieve deep sleep stages, resulting in poorer overall sleep quality.

Additionally, nicotine has an appetite-suppressing effect, which is well-documented. Many smokers report a reduction in their feelings of hunger, which can contribute to weight management or weight loss in some individuals. This combination of disrupting sleep and suppressing appetite is consistent with the pharmacological properties of nicotine as an addictive stimulant.

In contrast to the other options, nicotine does not induce sleep or stimulate deep sleep cycles, nor does it function primarily as a pain reliever. Therefore, the answer indicating that nicotine disrupts sleep and suppresses appetite accurately reflects its known effects on the body.