Leonie Belleville*Doctors often prescribe the antidepressant mirtazapine to treat depression. It is the Remeron brand-name drug's generic version. The group of medicines known as tetracyclic antidepressants includes mirtazapine. These drugs assist in regulating the neurotransmitters, or chemical messengers, in the brain that control mood. It has been demonstrated that mirtazapine affects various stages of sleep.