Which of the following medications has insomnia as a side effect?

The correct answer indicates that Zyprexa has insomnia as a side effect. Zyprexa, a medication primarily used to treat schizophrenia and bipolar disorder, affects neurotransmitters in the brain, such as dopamine and serotonin. Changes in these neurotransmitter levels can lead to side effects, including insomnia. Many individuals taking Zyprexa report changes in their sleep patterns, and while some experience increased sleepiness, others may have difficulty sleeping, leading to insomnia.

In contrast, Wellbutrin is known for its stimulating effects and can also cause insomnia in some cases due to its mechanism of action. Xanax is primarily used for anxiety and panic disorders and is more likely to cause drowsiness than insomnia. Zocor, a medication for lowering cholesterol, generally does not influence sleep patterns directly. This context helps to clarify why Zyprexa is linked to insomnia as a side effect among the options presented.