Bupropion
Buproprion, or Wellbutrin, is an NDRI, or norepinephrine and dopamine reuptake inhibitor, that helps with anxiety by balancing the levels of these chemicals in the brain. One of bupropion's side effects happens to be appetite suppression, which almost always leads to weight loss. Bupropion lessens oral fixations in patients taking the drug, and can be prescribed to help smokers quit smoking due to this effect.
Sertraline
Sertraline, or Zoloft, is an SSRI, or selective serotonin re-uptake inhibitor, used for the treatment of panic and depression disorders, along with social anxiety disorder and obsessive-compulsive disorder (OCD). Sertraline works by restoring the serotonin balance in the brain. Due to the side effects of appetite loss and nausea, anxiety patients on Zoloft have lost weight. Weight gain may be a side effect in some patients, too.
Fluoxetine
Fluoxetine, or Prozac, is another SSRI used by persons with depression, panic disorders, OCD and anxiety. Among Fluoxetine's known side effects reported by many patients is significant weight loss, though this is often due to nausea. It is also possible that some on this drug may actually gain weight.
Paroxetine
Paroxetine, or Paxil, is yet another SSRI that is used to not only treat depression, but also anxiety disorders, OCD and premenstrual dysmorphic disorder. On top of balancing the brain's serotonin levels as it is meant to do, Paroxetine has also been known to cause drowsiness, nausea, dizziness and weight loss in many patients taking the drug. Weight gain may be experienced by some.
Venlafaxine
Venlafaxine, or Effexor, is prescribed to patients plagued with anxiety disorders, major depressive disorders and panic disorders. Unlike the aforementioned medications, this drug is an SNRI, or serotonin-norepinephrine reuptake inhibitor, that restores the balance of the brain's serotonin and norepinephrine levels in order to improve mood problems. Venlafaxine often causes decreased appetite in patients taking the drug, in turn resulting in weight loss. In some persons, weight gain may be a side effect as well.
Alprazolam
Alprazolam, or Xanax, is in a group of drugs called benzodiazepines that slow down the movement of brain chemicals that have become unbalanced. Alprazolam is prescribed for patients with anxiety and panic disorders, as well as persons with anxiety caused by depression. Some of alprazolam's milder side effects are irritability, insomnia, nausea and weight loss due to changes in appetite.