University of Michigan Depression Center

Use of Medications

Antidepressant Medications

Depression is usually treated with either medication or psychotherapy, or both. Often, from a biological perspective, the causes of psychiatric disorders are called "chemical imbalances" because it is believed that abnormal amounts or functions of chemicals in the brain produce the symptoms and changes in behavior usually observed. The sources of these imbalances can be either genetic or environmental. It is likely that in most cases, the causes are multiple, including both genes and situational changes. For example, especially for depressed individuals who have several blood relatives with depression, genes are likely to be playing an important role in the source of the depression and even in the types of medications most likely to be beneficial. Other factors, such as stress-related environmental effects and learned changes in thought and behavior, are very frequently involved. Accumulating evidence indicates not only that genes can affect environmental responses, but also that environmental factors and behaviors can modulate gene action.

The chemicals present in the brain that control its functions (thoughts, emotions, motivations, normal and abnormal behaviors) are called neurotransmitters. There are a wide variety of these chemicals in the brain, and more are being discovered every year. Two of the earliest discovered and most important are serotonin and norepinephrine. These various substances are called neurotransmitters because they exist in neural tissue (brain and the rest of the nervous system) and transmit information between the nerve cells (called neurons). Information is passed in specialized regions between the cells called synapses when one neuron stimulates (or inhibits) the firing of another neuron. This occurs when the first neuron releases neurotransmitter molecules, that in turn affect the second neuron. The effect of the neurotransmitter chemical on the second neuron occurs at specialized areas on the neuron called receptors.

One important early theory of the biological cause of depression suggested that there was too little serotonin, and/or too little norepinephrine, in the brains of depressed people. This theory originated in part from the discovery that all drugs that relieved depression increased the effects of serotonin or norepinephrine. In the brain, the effects of both serotonin and norepinephrine are turned off by reuptake of the neurotransmitter molecules from the synapse into the first neuron, therefore stopping the effect on the second neuron. (For the system to work properly, it must turn on and turn off properly.) The primary mechanism by which drugs that treat depression work, is by decreasing the reuptake into the first neuron, leaving more to affect the second neuron. By the theory, this would relieve the effects of too little serotonin and/or norepinephrine. That is why many antidepressant drugs are called "reuptake inhibitors" (for example, why drugs like fluoxetine-Prozac-are often called "SSRIs"-Selective/Specific Serotonin Reuptake Inhibitors). More recent theories suggest more complex mechanisms for how these drugs relieve depression (and why they take weeks to do so), but reuptake blockade undoubtedly plays a role.

How well do antidepressants work in practice? They are used mainly for moderate or severe depressive symptoms. They can be used in combination with psychotherapy, which is often most effective. They typically take 1-3 weeks to have any benefit, and 1-3 months for full benefit. One-half to two-thirds of patients who are correctly diagnosed with major depressive disorder will respond to the first drug chosen, and 75% to 80% of patients will eventually respond if several different medications are given full trials. Overall, no type of antidepressant drug is more effective than any other, but the different types can have different side effects, and different drugs sometimes are more or less effective for different individuals. Many patients will have more than one disorder (co-morbidity). These individuals sometimes need additional treatment. Patients are more prone to relapse if they discontinue treatment before it is recommended (usually at least 4-6 months). The more severe the depression (more severe symptoms, longer duration of symptoms, prior episodes of depression earlier in their lives, many blood relatives with the same disorder, co-morbid disorders such as substance abuse, anxiety, personality disorder) the longer treatment should last, even up to life-long. The major causes of lack of treatment response include inadequate medication dose or length of treatment, wrong diagnosis, and patient non-adherence to treatment recommendations.

Treatments other than medications are available for depression. These include various methods of counseling and psychotherapy, so-called non-traditional treatment methods (such as herbal substances), and in more severe cases such methods as E.C.T. Placebos (substances or methods not known to have specific effects) produce improvement in about one-third of patients.

There are many sources of information about depression for patients and other interested individuals. Whether it is a book, a computer source, or advice of a friend, be open-minded but critical of the source and the information at the same time. Depression is a very common, and often quite debilitating illness, so there is a great deal of interest in the topic, but not always sufficient quality control for the claims made.

To Learn More About Medication, Visit These Sites:

NAMI: Medications used to treat depression
DEPRESSION CENTRAL: Drug Treatment for People with Mood Disorders

To Look Up Medications, Visit These Sites:

The Internet Drug Index
Internet Mental Health Medications