Antidepressant Drugs

Antidepressant drugs, also called antidepressants, are thought to work by influencing communication between cells in the brain. The drugs affect chemicals called neurotransmitters, which carry signals from one nerve cell to another. These neurotransmitters are involved in the control of mood and in other responses and functions, such as eating, sleep, pain, and thinking.

The main types of antidepressant drugs in use today are:

• Tricyclic antidepressants, such as amitriptyline (Elavil), imipramine (Tofranil), and nortriptyline (Pamelor).
• Selective serotonin reuptake inhibitors (SSRIs or serotonin boosters), such as fluoxetine (Prozac), paroxetine (Paxil), and sertraline (Zoloft).
• Monoamine oxidase inhibitors (MAO inhibitors), such as phenelzine (Nardil), and tranylcypromine (Parnate).
• Lithium (used mainly to treat manic depression, but also sometimes prescribed for recurring bouts of depression).

Selective serotonin reuptake inhibitors act only on the neurotransmitter serotonin, while tricyclic antidepressants and MAO inhibitors act on both serotonin and another neurotransmitter, norepinephrine, and may also interact with other chemicals throughout the body. Selective serotonin reuptake inhibitors have fewer side effects than tricyclic antidepressants and MAO inhibitors, perhaps because selective serotonin reuptake inhibitors act only on one body chemical, serotonin.

Because the neurotransmitters involved in the control of moods are also involved in other processes, such as sleep, eating, and pain, drugs that affect these neurotransmitters can be used for more than just treating depression. Headache, eating disorders, bed-wetting, and other problems are now being treated with antidepressants.

All antidepressant drugs are effective, but different types work best for certain kinds of depression. For example, people who are depressed and agitated do best when they take an antidepressant drug that also calms them down. People who are depressed and withdrawn may benefit more from an antidepressant drug that has a stimulating effect.