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Psychopharmacology

Psychopharmacology Made Basic

The medication mechanisms affecting our minds.

A clear understanding of today’s psychiatric drugs is essential. Emotional issues may call for a medical drug prescription. How the brain functions when medications are used is complex. An important consideration includes psychopharmacology. Intended drug effects have clear-cut aims. Unwanted side effects also occur.

This article addresses an understanding of “psych meds.” Psychopharmacology results in concrete changes in emotions, thinking, and the body’s functioning. Drugs improving attention and depression illustrate this. Examples that follow show how these actions appear in people’s lives.

F.J. Ninivaggi MD
Psychopharmacology: Basics
Source: F.J. Ninivaggi MD

Essential Psychopharmacology: Major Classes of Drugs

Psychotropic drugs include prescribed medications that treat psychiatric disorders. “Disorders” includes diagnoses, signs, symptoms, and other disturbances in mental functioning that are impairing.

Basic classes of drugs are defined by their principal actions on mental experience and neurochemistry. Here are some examples, with a generic drug name and then a trade name that begins with a capital letter.

· Antidepressants (e.g., escitalopram/Lexapro) target depression, low energy, and insomnia.

· Antipsychotics (e.g., atypical neuroleptics like aripiprazole/Abilify and quetiapine/Seroquel) target significant thinking disorders like psychosis and delusions and also help to stabilize mood.

· Mood stabilizers (e.g., valproic acid/Depakote and lithium) stabilize volatile, uneven mood and mood swings.

· Anxiolytics (e.g., lorazepam/Ativan) reduce anxiety.

· Hypnotics (e.g., zolpidem/Ambien) promote sleep.

· Psychostimulants (e.g., methylphenidate/Ritalin) treat attentional problems.

· Other classes (e.g., αlpha-2 adrenergic receptor agonists like guanfacine/Intuniv) can improve attention and concentration.

Although a class typically has a specific target, drugs have multiple applications. A drug can be used for universally shared symptoms across many conditions. An atypical neuroleptic such as aripiprazole used with a mood stabilizer such as lithium often improves the efficacy of mood stabilization in bipolar disorders. Thus, medications often share therapeutic actions. They can augment one another.

How Do Drugs Pharmacologically Improve Subjective Experience?

The pharmacological actions of drugs work by several mechanisms. Three major categories include:

1. Pharmacodynamics is what the drug does to the body via neurotransmitter receptors at a cellular level.

2. Pharmacokinetics is what the body itself does to a drug via absorption, distribution, metabolism, and excretion.

3. Pharmacogenetics is how an individual’s genetics affects a drug’s action via the liver’s metabolic handling of the drug, i.e., fast or slow metabolism of the medication.

Pharmacodynamics regulates the therapeutic effect of medications. The core event is drug action at the brain’s neuroreceptor sites with multiple locations where drugs attach or bind. How a drug works at a target site has additive or antagonistic effects, increasing, decreasing, or modulating actions.

Drugs act in relatively selective (not entirely specific) ways when they bind to their receptor sites, also known as "ligand binding." The characteristics of the dynamic attachment influence the kinetic onset and offset of a drug’s action. Dynamics and kinetics influence how long a drug’s effects will last.

Drugs characteristically upregulate/induce or downregulate/inhibit receptors. These changes modulate feeling and thinking: emotions, mood, and cognition. Agonist drugs bind to receptors, increasing receptor action. The agonist guanfacine increases norepinephrine in the brain regions, augmenting attention and focus. Antagonist drugs block receptor actions, deactivating undesirable effects. Aripiprazole blocks the D2 receptor and diminishes disorganized thinking.

Thus, a drug’s onset, duration, and offset correlate to changes in subjective experience. For example, pharmacokinetically, an agonist drug that binds quickly may increase its desirable effects and extend for hours. An example is guanfacine ER (extended release) for attentional problems such as ADHD (1). Absorption from the gastrointestinal tract is fast, peak plasma blood levels occur in one to three hours, and the “half-life elimination” from the body ranges from 10 to 30 hours. The elimination half-life of a drug is a pharmacokinetic event: the time it takes for the concentration of the drug in the plasma or the total amount in the body to reduce by 50%. Sympathetic nervous system tone improves, increasing focus and attention in the prefrontal cortex. Also, overactive and hyperkinetic behaviors lessen.

Drug Actions Affecting Emotions: Antidepressants

An often-prescribed drug class includes the antidepressants (2):

· fluoxetine (Prozac)

· sertraline (Zoloft)

· escitalopram (Lexapro)

· venlafaxine (Effexor)

· citalopram (Celexa)

· mirtazapine (Remeron)

Pharmacological Actions in a Person’s Life: Before and After Treatment

The clinical presentation of depression shows signs and symptoms affecting emotions, thinking, energy level, sleep, and appetite:

· Sadness

· Loss of the ability to feel interest or pleasure in everyday events

· Low self-esteem and worthlessness

· Social withdrawal

· Irritability

· Excessive guilt

· Indecisiveness

· Disturbances in energy, appetite, and sleep patterns

· About two-thirds contemplate suicide; 10 to 15% die of suicide

When these non-benign issues significantly impair a person’s life for two weeks or more, clinical depression is likely. A formal psychiatric evaluation confirms the diagnosis. A treatment plan may include psychotherapy, antidepressant medication, or both.

Effective psychopharmacology is patient-specific, dose-sensitive, and time-dependent.

Choice of drug rests on specific symptoms, the drug’s side effect profile (e.g., weight gain, sedation, etc.), and the collaborative informed decisions of provider and patient.

The treatment has three phases:

1.) acute for up to 12 weeks

2.) continuation from about four to nine months, and

3.) maintenance for one year or longer

Positive response to an antidepressant means about a 50% or greater reduction or remission of signs and symptoms. With treatment, recovery may begin in about three months. Psychiatric guidelines aim for full remission at four months. Full recovery may occur at one year. The course is variable. Remission of depression is recovery from impairing signs and symptoms for about one year or longer. Up to 65% of people achieve remission. Relapse occurs when recovery declines, and the symptomatic condition has a downward course.

The most common antidepressant drugs increase the brain neurotransmitter serotonin over two to four weeks. The body’s pharmacokinetics affect how the body absorbs the drug, breaks it down, and eliminates it. The drug’s pharmacodynamics shape how the drug binds to the brain’s receptors and raises low serotonin. While serotonin correlates with the antidepressant process, neurotransmitters such as norepinephrine and dopamine also play a part in shifts toward subjective improvement.

Thus, the abstract concept of psychopharmacology and its drug actions on brain receptors have real effects. Treatment changes how people sense their lives: emotional distress resolves, and well-being increases. Feeling well is being able to enjoy everyday events, relationships, and to work productively. This review is psychopharmacology made basic—understanding how medication mechanisms affect our minds and mental health.

References

1. Strange, B.C. (2008). Once-daily treatment of ADHD with guanfacine: patient implications. Neuropsychiatric Diseases and Treatment. 4(3): 499–506.

2.Insel, T. (2011). Antidepressants: A Complicated Picture. https://www.nimh.nih.gov/about/directors/thomas-insel/blog/2011/antidep… (NIMH, accessed May 20, 2019)

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