Question

Explain the ways in which the drugs prescribed to treat depression, schizophrenia, and anxiety work.

Answer 1

• Depression and schizophrenia are two of the many mental illnesses that a physician can treat with effective medications.
• Depression is often associated with various conditions including emotional upset (e.g., divorce, death in the family, major financial problems), co-existing medical conditions (e.g., stroke, heart attack, cancer), hormonal disorders (e.g., underactive thyroid, menopause) and problem substance use etc.
• Whatever the trigger, it is believed that the underlying biological basis of depression is a depletion in the levels of neurotransmitters such as serotonin, norepinephrine, and/or dopamine in the central nervous system.
• All antidepressants work in a similar way, though there are various types of antidepressants—often called “families”—that each work a bit differently. They all, however, increase the brain’s concentration of various neurotransmitters.
• One of the older antidepressant families, tricyclic antidepressants (TCAs), increase both norepinephrine and serotonin concentrations, generally speaking. However, some TCAs will increase serotonin concentrations more than they increase norepinephrine (e.g., clomipramine), and others increase norepinephrine concentrations more than serotonin concentrations (e.g., nortriptyline and desipramine).
• Monoamine oxidase inhibitor antidepressants (MAOIs) comprise another family. It includes medicines like phenelzine, isocarboxazid and moclobemide. MAOIs work by stopping the breakdown of monoamine neurotransmitters, which helps keep the brain’s concentration of neurotransmitters at levels that help improve mood.
• Newer antidepressants act in a similar way to treat depression, with the advantage of fewer side effects. The most commonly prescribed group of antidepressants is selective serotonin reuptake inhibitors (SSRIs), including fluoxetine, paroxetine, fluvoxamine, sertraline and citalopram. The main action of SSRIs is to increase the concentration of serotonin.
• Lastly, the anti­depressant mirtazapine enhances neurotransmission by increasing the concentrations of both serotonin and norepinephrine. Unlike the SSRIs, mirtazapine blocks specific serotonin receptors, reducing the potential to cause side effects such as sexual dysfunction and nausea.
• Antidepressents are also used to treat anxiety disorders.Anti-anxiety medications help reduce the symptoms of anxiety, such as panic attacks, or extreme fear and worry. The most common anti-anxiety medications are called benzodiazepines. Benzodiazepines can treat generalized anxiety disorder.
• Benzodiazepines (such as Lorazepam) and beta-blockers are used to treat the short-term symptoms of anxiety. Beta-blockers help manage physical symptoms of anxiety, such as trembling, rapid heartbeat, and sweating that people with phobias.
• Buspirone (which is unrelated to the benzodiazepines) is sometimes used for the long-term treatment of chronic anxiety.
• Schizophrenia is associated with an increase in dopamine activity in an area of the central nervous system called the meso­limbic pathway. The meso­limbic pathway is one of four major dopamine-related pathways in the brain that is associated with pleasurable feelings, with addiction—and with psychosis.
• Anti­psychotic medications work by blocking a specific subtype of the dopamine receptor, referred to as the D2 receptor. Older antipsychotics, known as conventional antipsychotics, block the D2 receptor and improve positive symptoms.
• A second generation of antipsychotics, commonly referred to as the atypical antipsychotics, block D2 receptors as well as a specific subtype of serotonin receptor.