When I first began to suffer from severe depression, a little over two decades ago - there were two primary types of medication being used to treat depression. Either stimulants, or sedatives.
The first medication that was ever prescribed for my depression was Valium. This was a disastrous medication route to take, for someone who was suffering from the negative and depressive or "down" impact of depression, already.
Ten to fifteen years later, anti depressants are in competely different categories than they once were.
Their are many options, and only the person from suffering from mental illness, and their psychiatrist can make the correct decisions about which medications will be the most helpful in any given situation.
One thing I have learned is that the prescription process is sort of hit or miss. In general, psychiatrists can't be sure if a specific type of medication is going to help, until the patient has been on it for six to eight weeks. Prior to that, efficacy can't be determined.
On HealthyPlace.com, I found a good description of the different types of anti depressants, and the theories about how or why they work:
How Antidepressants Work
Most antidepressants are believed to work by slowing the removal of certain chemicals from the brain. These chemicals are called neurotransmitters (such as serotonin and norepinephrine). Neurotransmitters are needed for normal brain function and are involved in the control of mood and in other responses and functions, such as eating, sleep, pain, and thinking.
Antidepressants help people with depression by making these natural chemicals more available to the brain. By restoring the brain's chemical balance, antidepressants help relieve the symptoms of depression.
Specifically, antidepressant drugs help reduce the extreme sadness, hopelessness, and lack of interest in life that are typical in people with depression. These drugs also may be used to treat other conditions, such as obsessive compulsive disorder, premenstrual syndrome, chronic pain, and eating disorders.
Typically, antidepressants are taken for 4 to 6 months. In some cases, however, patients and their doctors may decide that antidepressants are needed for a longer time.
There are many different kinds of antidepressants, including:
Like most medicines, antidepressant drugs can cause side effects. Not all people get these side effects. Any side effects you have will depend on the medicine your doctor has chosen for you. Your doctor should talk to you about your medicine.
SSRIs are a group of antidepressants that includes drugs such as escitalopram (brand name: Lexapro) citalopram (brand name: Celexa), fluoxetine (brand name: Prozac), paroxetine (brand name: Paxil) and sertraline (brand name: Zoloft). 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. Some of the side effects that can be caused by SSRIs include dry mouth, nausea, nervousness, insomnia, headache and sexual problems. People taking fluoxetine might also have a feeling of being unable to sit still. People taking paroxetine might feel tired. People taking sertraline might have runny stools and diarrhea.
The tricyclics have been used to treat depression for a long time. They act on both serotonin and another neurotransmitter, norepinephrine, and may also interact with other chemicals throughout the body. They include amitriptyline (brand name: Elavil), desipramine (brand name: Norpramin), imipramine (brand name: Tofranil) and nortriptyline (brand names: Aventyl, Pamelor). Common side effects caused by these medicines include dry mouth, blurred vision, constipation, difficulty urinating, worsening of glaucoma, impaired thinking and tiredness. These antidepressants can also affect a person's blood pressure and heart rate.
Other antidepressants exist that have different ways of working than the SSRIs and tricylics. Commonly used ones are venlafaxine, nefazadone, bupropion, mirtazapine and trazodone. Less commonly used are the monoamine oxidase inhibitors (MAOIs).
Some of the most common side effects in people taking venlafaxine (brand name: Effexor) include nausea and loss of appetite, anxiety and nervousness, headache, insomnia and tiredness. Dry mouth, constipation, weight loss, sexual problems, increased blood pressure, increased heart rate and increased cholesterol levels can also occur.
Nefazodone (brand name: Serzone) can give people headaches, blurred vision, dizziness, nausea, constipation, dry mouth and tiredness.
Bupropion (brand name: Wellbutrin) can cause agitation, insomnia, headache and nausea. Mirtazapine (brand name: Remeron) can cause sedation, increased appetite, weight gain, dizziness, dry mouth and constipation. Some of the most common side effects of trazodone (brand name: Desyrel) are sedation, dry mouth and nausea. MAOI antidepressants like phenelzine (brand name: Nardil) and tranylcypromine (brand name: Parnate) commonly cause weakness, dizziness, headaches and tremor.
The U.S. Food and Drug Administration (FDA) ordered makers of all antidepressant medications to include a "black box warning" (the most serious warning) on their products' labeling to include warnings about increased risks of suicidal thinking and behavior, known as suicidality, in children, adolescents and young adults (ages 18 to 24) during initial treatment (generally the first one to two months).
IMPORTANT SAFETY INFORMATION – Depression and certain other psychiatric disorders are themselves associated with increases in the risk of suicide. Antidepressants increased the risk of suicidality (suicidal thinking and behavior) in children, adolescents, and young adults in short-term studies of major depressive disorder (MDD) and other psychiatric disorders. Anyone considering the use of antidepressants in children, adolescents or young adults must balance the risk to clinical need. Patients of all ages started on antidepressant therapy should be closely monitored and observed for clinical worsening, suicidality or unusual changes in behavior, especially at the beginning of therapy or at the time of dose changes. This risk may persist until significant remission occurs. Families and caregivers should be advised of the need for close observation and communication with the prescriber. Lexapro is not approved for use in pediatric patients.
I hope this information is helpful to anyone who is reading this, especially if they are considering anti-depressants for the first time.