Anti-depressants are a very commonly prescribed drug these days, perhaps too commonly prescribed. With the stress of everyday life, more and more people are going to their doctors for pharmaceutical help in coping. Not to say that there aren't times when medication is needed, for when there is a chemical imbalance in the brain medication is helpful and necessary to restore balance. The problem is that many doctors prescribe antidepressants for any patient who says they are feeling a little down or stressed out.
Most antidepressants are believed to work by slowing the removal of certain chemicals from the brain.
These chemicals are called neurotransmitters. Neurotransmitters are needed for normal brain function. Antidepressants help people with depression by making these natural chemicals more available to the brain. There are six groups of antidepressants and each work on different neurotransmitters. Most are reuptake inhibitors.
Reuptake, or uptake, is a chemical process that occurs in the brain. It is defined as the reabsorption of a neurotransmitter after it has performed its function of transmitting a neural impulse. In effect, what happens is that the neurotransmitter, once reabsorbed, is no longer available in the active synapses of the brain. Reuptake inhibitors, by slowing down the reabsorption of these chemicals allow the brain to function more normally.See also anti anxiety medication
1. Selective serotonin reuptake inhibitors (SSRIs)
Deficiencies in serotonin availability have been linked to depression, anxiety, irregular appetite, aggression and pain sensation.
The SSRI's are:
These medicines tend to have fewer side effects than other antidepressants. Some of the side effects that can be caused by SSRIs include dry mouth, nausea, nervousness, insomnia, sexual problems and headache.
From the 1960s through the 1980s, tricyclic antidepressants (named for their chemical structure) were the first line of treatment for major depression. Most of these medications affected two chemical neurotransmitters, norepinephrine and serotonin. Though the tricyclics are as effective in treating depression as the newer antidepressants, their side effects are usually more unpleasant; thus, today tricyclics are used as a second- or third-line treatment.
The tricyclics are:
amitriptyline (brand name: Elavil)
desipramine (brand name: Norpramin)
imipramine (brand name: Tofranil)
nortriptyline (brand name: Aventyl, Pamelor)
3. Serotonin and norepinephrine reuptake inhibitors (SNRIs)
Norepinephrine is a neurotransmitter that is similar to adrenaline. High levels of norepinephrine can cause hostile behavior. Norepinephrine along with dopamine and phenylethalimine create feelings of infatuation. If children undergo excessive amounts of stress, they can acquire a permanent deficiency in serotonin and high levels of norepinephrine, which can lead to long-term, aggressive behavior.
The nervous system responds to short-term stress with norepinephrine and epinephrine (adrenaline), which increase the heart rate and blood pressure. They also cause other actions within the body that prepare a person for a stressful situation. All of these chemical actions in the brain are responsible for launching a person into their natural defense mode. (Fight or Flight)
venlafaxine (brand name: Effexor)
4. Norepinephrine and dopamine reuptake inhibitors (NDRIs)
Dopamine is a type of neurotransmitter. It is a chemical messenger that is similar to adrenaline and affects the brain processes that control movement, emotional response and the capacity to feel pleasure and pain. Dopamine is vital for performing balanced and controlled movements. A shortage of dopamine can cause a lack of controlled movements such as those experienced in Parkinson disease.
Dopamine moves into the frontal lobe and regulates the flow of information coming in from other areas of the brain. A shortage or problem with the flow of dopamine can cause a person to lose the ability to think rationally, demonstrated in schizophrenia. Also, an excess of dopamine in the limbic system and not enough in the cortex may produce a suspicious personality and possible paranoia. A shortage of Dopamine in the frontal lobe can reduce one's memory. An increase of dopamine into the frontal lobe relieves pain and boosts feelings of pleasure.
The NDRI's are:
Some of the common side effects in people taking NDRIs include agitation, nausea, headache, loss of appetite and insomnia. It can also cause increase blood pressure in some people.
5. Combined reuptake inhibitors and receptor blockers
These combine reuptake inhibitors with receptor blockers. Receptors are areas of the brain that chemicals affect. Each receptor is specific to a certain type of chemical. They work with a lock and key action. That is, once a chemical has entered the receptor it locks out any other chemicals. Therefore, when a blocker drug enters the receptor, it blocks out any other chemicals from entering.
The combination drugs are:
trazodone (brand name: Desyrel)
nefazodone (brand name: Serzone)
mirtazpine (brand name: Remeron)
Common side effects of these medicines are drowsiness, dry mouth, nausea and dizziness.
6. Monamine oxidase inhibitors (MAOIs)
Once the brain's three neurotransmitters, known as monoamines (serotonin, norepinephrine, and dopamine), have played their part in sending messages in the brain, they get burned up by a protein in the brain called monoamine oxidase, a liver and brain enzyme. If too many monoamines are absorbed, it leads to a chemical imbalance in the brain.
Monoamine oxidase inhibitors, or MAOI's work by blocking this cleanup activity. When the excess neurotransmitters don't get destroyed, they start piling up in the brain. And since depression is associated with low levels of these monoamines, increasing the monoamines ease depressive symptoms.
The MAOI's are:
isocarboxazid (brand name: Marplan)
phenelzine (brand name: Nardil)
tranlcypromine (brand name: Parnate)