Psychiatric medications can be an effective treatment for mental illnesses. Although psychiatric medications don't cure mental illness, they can often significantly improve symptoms, whether you have depression, schizophrenia or another condition. Psychiatric medications also can help make other treatments, such as psychotherapy, more effective.

In some cases, specific psychiatric medications are approved by the Food and Drug Administration (FDA) to treat a particular type of mental illness. However, medications are often used to treat conditions for which they're not officially approved — a common and perfectly legal practice called off-label use. For instance, fluoxetine (Prozac, Prozac Weekly) is FDA approved to treat depression, panic disorder and several other mental illnesses. It's not specifically approved to treat generalized anxiety disorder, but it may be prescribed to treat that disorder.

Here's an overview of some of the most commonly used classes of prescription psychiatric medications.

Antidepressants are used to treat various types of depression. Several types of antidepressants, grouped by how they affect brain chemistry, are available. Antidepressants can help improve such depression symptoms as sadness, hopelessness, lack of energy, difficulty concentrating and lack of interest in activities. Antidepressants are often used to treat illnesses besides depression, including nonpsychiatric conditions. Antidepressant medications include citalopram (Celexa), paroxetine (Paxil, Paxil CR) and many others.

Mood stabilizer is the colloquial name given to psychiatric medications that treat both manic and depressive symptoms. Mood stabilizers are most commonly used to treat bipolar disorder, which is characterized by alternating episodes of mania and depression. Mood stabilizers may also include anti-seizure medications. Mood-stabilizing medications include lithium (Eskalith, Lithobid), divalproex (Depakote) and many others.

Anti-anxiety medications, as their name suggests, are used to treat anxiety disorders, such as generalized anxiety disorder and panic disorder. They may also be useful in helping relieve agitation and insomnia. These medications are typically fast acting, helping relieve symptoms in as little as 30 minutes. A major drawback, however, is that they may cause dependency. Anti-anxiety medications include alprazolam (Xanax), lorazepam (Ativan) and many others.

Antipsychotic medications, also called neuroleptics, are typically used to treat psychotic disorders, such as schizophrenia. A person who is psychotic is plagued by delusions and is unable to maintain a hold on reality. Antipsychotic medications may also be used to treat severe cases of depression accompanied by psychosis. Antipsychotic medications include clozapine (Clozaril), olanzapine (Zyprexa) and many others.