Which SSRI is most commonly associated with weight gain?

Paroxetine is the selective serotonin reuptake inhibitor (SSRI) most commonly associated with weight gain among the options provided. It is known to have a tendency to cause weight gain due to its effects on metabolism and appetite regulation. Additionally, it can affect the hormonal pathways related to weight management, making it more likely for users to experience an increase in weight during treatment.

In contrast, other SSRIs like sertraline and fluvoxamine are generally considered to have a more neutral effect on weight, and in some cases, sertraline has been associated with weight loss in certain individuals. Duloxetine, although primarily a serotonin-norepinephrine reuptake inhibitor (SNRI) rather than an SSRI, has also been shown to have a lower incidence of weight gain. Therefore, paroxetine stands out in this context as the SSRI that most frequently leads to weight gain as a side effect.