Final answer:
Paroxetine is the medication most likely to cause withdrawal symptoms if abruptly discontinued for depressive disorder.
Step-by-step explanation:
The medication most likely to cause withdrawal symptoms if abruptly discontinued for depressive disorder is Paroxetine. Paroxetine belongs to a class of drugs called selective serotonin reuptake inhibitors (SSRIs). These medications affect the levels of serotonin in the brain, and sudden discontinuation of Paroxetine can lead to withdrawal symptoms such as dizziness, nausea, headache, insomnia, and anxiety.