Medication that treats depression can also help patients with anxiety disorders. Antidepressants balance chemicals or neurotransmitters in the brain that affect emotions and moods, improving mental health conditions. Some people have anxiety as a side effect of depression and people with anxiety difficulties can also suffer from depressive moods. Doctors may change medication for patients during treatment until the right medication or dosage relieves the conditions.

Newer antidepressants have fewer side effects than older medications. They include such drugs as fluoxetine, paroxetine, sertraline and citalopram. These drugs work to treat depression and such anxiety disorders as panic disorder, obsessive-compulsive behavior, post-traumatic stress and social phobias, according to the National Institute of Mental Health. The drugs belong to a class of medications called selective serotonin reuptake inhibitors. They increase levels of serotonin to improve mental balance and relieve depression and anxiety symptoms. Side effects may include nervousness, insomnia and decreased sexual desire. Adjustment to the medication or dosage may relieve side effects.

Drugs to treat depression and generalized anxiety disorder include venlafaxine and duloxetine. The drugs, called serotonin and norepinephrine reuptake inhibitors, work the same way by increasing serotonin and norepinephrine levels for improvement in moods. Generalized anxiety disorder causes people to worry excessively about everyday situations involving family, health or work. Many patients also suffer from depression. The medication reduces symptoms for both conditions. The drugs have similar side effects to serotonin reuptake inhibitors.

Tricyclic antidepressants have been used for many years and can work as effectively as new medications, according to MayoClinic.com. They may cause more side effects, including low blood pressure, blurred vision, rapid heartbeat and confusion. However, because each patient’s condition is different, tricyclics may work better on some people than others. The drugs work for most anxiety disorders as well as depression.

Older medications include monoamine oxidase inhibitors, such as phenelzine and tranylcypromine. The drugs work to treat depression, panic disorder and social phobias. They can have serious side effects when combined with certain foods and medications. Doctors usually inform patients on what products to avoid when taking these drugs to prevent risky increases in blood pressure or other side effects.

Treating depression and anxiety may also include a combination of drug therapies. Anti-anxiety medications or stimulants may work alongside antidepressants to improve conditions. It may take several weeks or months before patients find the right combination. Patients also undergo psychotherapy as part of their treatment with medication.