In fact, eliminating all anxiety may eliminate adaptive responses to stress. Two broad classes of drugs may be used for treatment of patients with anxiety and depression. Antidepressants work well not only for depression but also are effective for a number of anxiety disorders and for anxiety with depression. Anxiolytics may also be used in these patients, but are not generally as helpful. All of these drugs work by affecting one or more of the neurotransmitter systems.
Several drugs are available that work on both serotonergic and noradrenergic systems.
Imipramine and amitriptyline are very efficacious if patients can tolerate adequate dosages. Clomipramine and venlafaxine also are mixed re-uptake inhibitors. While depression started to improve after two weeks of treatment in patients treated with either drug, symptoms of anxiety did not respond until approximately eight weeks. When complete remission rather than response is considered, the difference between selective and mixed re-uptake inhibitors is more evident. Some disorders are best treated by drugs that work by interacting with one system or the other.