Study Notes on Psychiatric Disorders from Principles of Pharmacology for Athletic Trainers

Chapter 13: Psychiatric Disorders

Overview

  • Authors: Houglum J, Harrelson G.

  • Source: Principles of Pharmacology for Athletic Trainers, Second Edition. © 2011 SLACK Incorporated.

Major Neurotransmitters in the Brain

  • Neurotransmitters play essential roles in signaling, with key types including:

    • Serotonin (5-HT)

    • Norepinephrine (NE)

    • Dopamine (DA)

    • γ-Aminobutyric acid (GABA)

  • They are housed in vesicles, transported by transporters, and act on receptors on the cell surface.

Major Depression

  • Definition: A mood disorder characterized by persistent feelings of sadness and loss of interest.

  • Causes:

    • Not fully understood but involves decreased levels of serotonin and norepinephrine.

    • Can onset due to medications or medical conditions.

    • Affects women twice as frequently as men and is not dependent on age.

Symptoms of Major Depression

  • Important symptoms include:

    • Depressed mood

    • Loss of interest or pleasure in activities

    • Change in appetite or sleep patterns

    • Loss of energy

    • Feelings of worthlessness or guilt

    • Diminished ability to concentrate

    • Suicidal thoughts

Antidepressants

  • Categories include:

    • Tricyclic Antidepressants (TCAs)

    • Selective Serotonin Reuptake Inhibitors (SSRIs)

    • Monoamine Oxidase Inhibitors (MAOIs)

    • Serotonin-Norepinephrine Reuptake Inhibitors (SNRIs)

Selective Serotonin Reuptake Inhibitors (SSRIs)

  • Definition: These are currently the most commonly used antidepressants.

  • Mechanism of Action (MOA): They inhibit the reuptake of serotonin in presynaptic neurons, enhancing serotonin levels in the synaptic cleft.

  • Examples:

    • Fluoxetine (Prozac, Sarafem)

    • Sertraline (Zoloft)

    • Paroxetine (Paxil, Paxil CR)

    • Fluvoxamine (Luvox)

    • Citalopram (Celexa)

    • Escitalopram (Lexapro)

Adverse Effects of SSRIs

  • Common side effects include:

    • Sexual dysfunction

    • Nausea and vomiting

    • Headache

    • CNS stimulation

    • Potential “Serotonin Syndrome”

Therapy Considerations for SSRIs

  • Time of Day Taken: Administration in the morning is often preferred.

  • Onset of Effect: Slow effect with maximum response in 4 to 6 weeks.

  • Discontinuation: Must gradually decrease the dose when discontinuing the medication.

Serotonin/Norepinephrine Reuptake Inhibitors (SNRIs)

  • Influence on serotonin and norepinephrine levels, having a better side effect profile than TCAs.

  • Examples:

    • Venlafaxine (Effexor)

    • Duloxetine (Cymbalta)

    • Desvenlafaxine (Pristiq)

Tricyclic Antidepressants (TCAs)

  • Mechanism of Action: Block the reuptake of serotonin and norepinephrine and also block cholinergic receptors.

  • Examples:

    • Imipramine (Tofranil)

    • Amitriptyline (Elavil)

    • Nortriptyline (Pamelor)

    • Desipramine (Norpramin)

    • Clomipramine (Anafranil)

    • Doxepin (Sinequan)

    • Protriptyline (Vivactil)

    • Trimipramine (Surmontil)

Adverse Effects of TCAs

  • Notable side effects include:

    • Orthostatic hypotension

    • Anticholinergic effects

    • Sedation

    • Cardiac toxicity

    • Seizures

    • Weight gain

    • Sexual dysfunction

    • Increased sweating

TCA Therapy Considerations

  • Onset of Action: Slow, requires about 3 to 4 weeks.

  • Noncompliance Rate:High due to adverse effects.

  • Narrow Therapeutic Index: Abrupt discontinuation leads to withdrawal symptoms.

Monoamine Oxidase Inhibitors (MAOIs)

  • Rarely Used:

    • They inhibit monoamine oxidase, thus decreasing the breakdown of norepinephrine and serotonin.

    • Known for many drug and food interactions.

  • Examples: Nardil and Parnate.

Bupropion

  • Indicated for major depression and smoking cessation.

  • Mechanism: Mild norepinephrine/dopamine reuptake inhibitor.

  • Considerations: Well tolerated; can cause seizures at higher doses.

Tetracyclics

  • Affect multiple receptors and increase serotonin and norepinephrine.

  • Example: Mirtazapine.

  • Adverse Effects: Include somnolence, dizziness, weight gain, increased cholesterol, and mild anticholinergic effects.

Trazodone (Desyrel)

  • Less effective compared to other antidepressants.

  • Primarily causes significant sedation and is used for insomnia.

  • Other Adverse Effects: Dizziness and orthostatic hypotension.

Bipolar Disorder

  • Serious mental disorder characterized by mood swings ranging from manic episodes to depressive states.

Symptom Domains of Bipolar Disorder

  • Manic mood and behavior:

    • Euphoria

    • Grandiosity

    • Pressured speech

    • Impulsivity

    • Excessive libido

  • Dysphoric or Negative Mood:

    • Depression, anxiety, irritability, hostility, violence, recklessness, diminished need for sleep, social intrusiveness, and psychotic symptoms (delusions and hallucinations).

  • Cognitive Symptoms:

    • Racing thoughts, distractibility, disorganization, inattentiveness.

Treatment of Bipolar Disorder

  • Antidepressants: Used to treat acute depressive episodes but with lower doses and shorter durations than for major depression.

  • Lithium (Li+):

    • Uses: Treats acute manic episodes and prevents reoccurrence of mania and depression.

    • MOA: Unclear.

    • Adverse Effects: Nausea, diarrhea, confusion, muscle weakness, headache, polydipsia, polyuria, fine hand tremors. Long-term effects may include renal toxicity, goiter, and hypothyroidism.

    • Therapy Considerations: Requires multiple daily doses due to a low therapeutic index and toxicity risk. Advise patients to stay hydrated (2-3 liters of water daily).

Valproic Acid (VPA)

  • A mood stabilizer with an unknown mechanism, effective for acute manic episodes and maintenance therapy.

  • Adverse Effects: Might include nausea, diarrhea, sedation, weight gain, prolonged bleeding time, alopecia, hepatitis, thrombocytopenia.

Carbamazepine

  • Another mood stabilizer for acute mania and maintenance therapy, with an unclear mechanism.

  • Adverse Effects: Nausea, vomiting, diarrhea, drowsiness, confusion, headache, dizziness, vertigo, blurred vision.

    • Drug Interactions: Induces P450 enzymes, increasing metabolism of other drugs and its own metabolism, while inhibitors increase its concentration.

Antipsychotics in Bipolar Disorder

  • Used alone or with mood stabilizers for treating acute manic episodes and maintenance therapy.

  • Atypical Antipsychotics: Generally preferred.

Anxiety Disorders

  • Characterized by excessive fear or anxiety in a way that disrupts daily function.

  • Key neurotransmitters involved include norepinephrine, serotonin, dopamine, and GABA.

Generalized Anxiety Disorder (GAD)

  • Defined as excessive, uncontrollable worry lasting over six months, often co-existing with other psychiatric disorders.

Panic Disorder

  • Involves recurrent panic attacks coupled with persistent concerns and behavior changes regarding the attacks.

Social Anxiety Disorder (SAD)

  • The most common anxiety disorder characterized by intense fear of negative evaluation in social situations, leading to avoidance behavior.

Obsessive-Compulsive Disorder (OCD)

  • Characterized by obsessions (recurring intrusive thoughts) and compulsions (ritualistic behavior).

Post-Traumatic Stress Disorder (PTSD)

  • Develops following a traumatic event, involving symptoms such as flashbacks and recurring thoughts of the event.

Drug Therapy for Anxiety Disorders

  • SSRIs and SNRIs are the preferred treatments, alongside benzodiazepines and buspirone (BuSpar), especially for generalized anxiety disorders.

  • Benzodiazepines:

    • MOA: Potentiate GABA effects, causing CNS depression. They have potential for abuse and withdrawal symptoms.

    • Examples: Alprazolam, Lorazepam, Diazepam, Clonazepam.

Buspirone

  • Duration: Takes 4 to 6 weeks for maximum effect with no abuse potential.

  • Considerations: Good long-term therapy option for anxiety without sedation.

Treatment Strategies

  • Performance Anxiety: β-blockers are commonly used to alleviate autonomic symptoms. Administered prior to events for management of stage fright.

Obsessive-Compulsive Disorder Treatment

  • SSRIs are the primary treatment, with the average dose higher than that used for other anxiety disorders.

Schizophrenia

  • A chronic mental disorder with a complex etiology likely involving a genetic component and neurotransmitter disturbances, primarily dopamine and serotonin.

Symptoms of Schizophrenia

  • Divided into positive, negative, and cognitive symptoms:

    • Positive Symptoms: Hallucinations, delusions, paranoia.

    • Negative Symptoms: Diminished motivation, emotional expression, and social withdrawal.

    • Cognitive Symptoms: Disordered thoughts, attention deficits, and memory difficulties.

Antipsychotic Treatments

  • Typical Antipsychotics: Such as Haloperidol and Chlorpromazine, with notable side effects like extrapyramidal symptoms.

  • Atypical Antipsychotics: Considered the drugs of choice due to a lower risk of extrapyramidal side effects and broader efficacy.

    • Examples: Clozapine, Olanzapine, Risperidone, Quetiapine, Ziprasidone, Paliperidone, Aripiprazole.

  • Clozapine: Noted for its effectiveness but has a risk of agranulocytosis requiring regular blood monitoring.

Treatment Goals for Schizophrenia

  • Address acute episodes, prevent recurrences, optimize functioning, minimize side effects, and improve adherence. Atypical agents are first-line except for Clozapine.

Attention Deficit/Hyperactivity Disorder (ADHD)

  • Characterized by inattention, hyperactivity, and impulsivity, with genetic links suggested.

Treatment Goals

  • Aim to improve focus, reduce impulsivity, and minimize adverse effects of therapy.

Drug Therapy for ADHD

  • Central Nervous System (CNS) stimulants are frequently used:

    • Examples:

    • Methylphenidate (Ritalin)

    • Dexmethylphenidate (Focalin)

    • Amphetamines (Adderall, Vyvanse).

  • Adverse Effects of CNS Stimulants: Decreased appetite, insomnia, anxiety, irritability, and rapid speech.

Non-Stimulant Treatment Options

  • Atomoxetine (Strattera): Selective norepinephrine reuptake inhibitor, with considerations around increased suicide risk.

Sleep Disorders

  • Disorders characterized by disrupted sleep patterns.

Types of Sleep Disorders

  • Insomnia: Difficulty falling or staying asleep.

  • Narcolepsy: Excessive daytime sleepiness treated with CNS stimulants such as Modafinil.

  • Sleep Apnea: Treated with devices like CPAP.

Drug Therapy for Sleep Disorders

  • Benzodiazepines and Benzodiazepine-like Drugs: Common options for insomnia, with drug therapy recommendations aimed at employing the lowest effective doses for the shortest time.

  • Antidepressants: Certain antidepressants used off-label for sleep issues, such as amitriptyline and trazodone.

OTC Sleep Aids

  • Common options include first-generation antihistamines like diphenhydramine, melatonin supplements, and valerian root, each considered for their effects on promoting sleep onset.

Eating Disorders

  • Major types include:

    • Anorexia Nervosa: Characterized by self-imposed starvation and excessive thinness.

    • Bulimia Nervosa: Characterized by binge eating followed by purging.

Treatment Approaches

  • Primarily involve psychotherapy and nutritional counseling.

  • Anorexia nervosa currently lacks FDA-approved medications, while bulimia nervosa sees use of SSRIs, particularly Fluoxetine which is FDA approved.