Chapter 2: Neurobiologic Theories and

Psychopharmacology

Great strides are being made in understanding the brain and mental illness, but much is still unknown; nurses need to keep abreast of developments to provide effective teaching

Neurobiologic TheoriesNeurobiologic Theories

Central Nervous SystemCentral Nervous System

Consists of:

• Brain

– Cerebrum

– Cerebellum

– Brain stem

– Limbic system

• Spinal cord

• Nerves that control voluntary acts

CerebrumCerebrumDivided into two hemispheres with four lobes

each: Frontal lobe (thought, body movement,

memories, emotions, moral behavior) Parietal lobe (taste, touch, spatial

orientation) Temporal lobe (smell, hearing, memory,

emotional expression)

Occipital lobe (language, visual interpretation)

CerebellumCerebellum

•Receives and integrates information from all body areas to coordinate movement and posture

Brain StemBrain Stem

•Midbrain

– Pons

– Medulla oblongata

– Locus ceruleus

– Cranial nerve nuclei 3 through 12

Limbic SystemLimbic System

•Above the brain stem and includes:

– Thalamus

– Hypothalamus

– Amygdala

NeurotransmittersNeurotransmitters

Chemical substances manufactured in the neuron to aid in transmission of information

• Either inhibitory or excitatory

Neurotransmitters include:Neurotransmitters include:

Dopamine (control of complex movements, motivation, cognition, regulation of emotional responses)

Norepinephrine (attention, learning, memory, sleep, wakefulness, mood regulation)

Epinephrine (flight-or-fight response)

Serotonin (food intake, sleep, wakefulness, temperature regulation, pain control, sexual behaviors, regulation of emotions)

Neurotransmitters include: (cont’d)Neurotransmitters include: (cont’d)

Histamine (alertness, control of gastric secretions, cardiac stimulation, peripheral allergic responses)

• Acetylcholine (sleep and wakefulness cycle, signals muscles to become alert)

Glutamate (an excitatory amino acid)

GABA (modulates other neurotransmitters)

Brain Imaging TechniquesBrain Imaging Techniques

Include:

• Computed tomography (CT)

• Magnetic resonance imaging (MRI)

• Positron emission tomography (PET)

• Single photon emission computed tomography (SPECT)

We cannot yet diagnose mental illness with these techniques alone.

Axial PET of Male Patient With Alzheimer’s

Causes of Mental IllnessCauses of Mental Illness

•Genetics and heredity: play a role but alone do not account for development of mental illness

•Psychoimmunology: a compromised immune system could contribute, especially in at-risk populations

•Infections, particularly viruses, may play a role

PsychopharmacologyPsychopharmacology

Psychopharmacology and medication management are important in the treatment of many mental illnesses.

Principles that guide the use of medications include:

Effect on target symptom

Adequate dosage for sufficient time

Lowest dose needed for maintenance

Lower doses for the elderly

Tapering rather than abrupt cessation to avoid rebound or withdrawal

Follow-up care

Simplify the regimen for increased compliance

Antipsychotic Drugsconventional; atypical; new generationconventional; atypical; new generationAntipsychotic Drugsconventional; atypical; new generationconventional; atypical; new generation

Uses:

Schizophrenia, acute mania, psychotic depression, drug-induced psychosis, other psychotic symptoms

Action:

Treat psychotic symptoms, such as delusions and hallucinations, by blocking dopamine receptors

Conventional Antipsychotic Drugsphenothiazines (Thorazine, Prolixin, Mellaril, Stelazine); phenothiazines (Thorazine, Prolixin, Mellaril, Stelazine); Navane, Haldol, Loxitane, MobanNavane, Haldol, Loxitane, Moban

Conventional Antipsychotic Drugsphenothiazines (Thorazine, Prolixin, Mellaril, Stelazine); phenothiazines (Thorazine, Prolixin, Mellaril, Stelazine); Navane, Haldol, Loxitane, MobanNavane, Haldol, Loxitane, Moban

Side Effects

• Extrapyramidal side effects (EPSs)

• Pseudoparkinsonism

• Dystonia

• Akathisia

• Anticholinergic side effects

• Tardive dyskinesia (TD)

• Neuroleptic malignant syndrome (NMS)

Patient Teaching

• Adhering to medication regimen

• Managing side effects

– Thirst

– Constipation

– Sedation

Atypical Antipsychotic DrugsClozaril, Risperdal, Zyprexa, Seroquel, GeodonClozaril, Risperdal, Zyprexa, Seroquel, GeodonAtypical Antipsychotic DrugsClozaril, Risperdal, Zyprexa, Seroquel, GeodonClozaril, Risperdal, Zyprexa, Seroquel, Geodon

Side Effects

• Fewer EPSs

• Weight gain

• Agranulocytosis (Clozaril)

Patient Teaching

• Adhering to medication regimen

• Reducing sugar and caloric intake

• Clozaril

– Weekly WBC monitoring

– Discontinue medication and seek care at first sign of infection

New-Generation Antipsychotic Drugsaripiprazole (Abilify)aripiprazole (Abilify)New-Generation Antipsychotic Drugsaripiprazole (Abilify)aripiprazole (Abilify)

Side Effects

• Headache

• Anxiety

• Nausea

Patient Teaching

• Adhering to medication regimen

Antidepressant DrugsSSRIs; TCAs; MAOIsSSRIs; TCAs; MAOIsAntidepressant DrugsSSRIs; TCAs; MAOIsSSRIs; TCAs; MAOIs

Uses:

Major depression, panic disorder and other anxiety disorders, bipolar depression, psychotic depression

Action:

Interact with the monoamine neurotransmitter systems in the brain, particularly the neurotransmitters norepinephrine and serotonin

SSRI Antidepressant Drugsfluoxetine (Prozac), paroxetine (Paxil), sertraline (Zoloft), fluoxetine (Prozac), paroxetine (Paxil), sertraline (Zoloft), citalopram (Celexa), escitalopram (Lexapro)citalopram (Celexa), escitalopram (Lexapro)

SSRI Antidepressant Drugsfluoxetine (Prozac), paroxetine (Paxil), sertraline (Zoloft), fluoxetine (Prozac), paroxetine (Paxil), sertraline (Zoloft), citalopram (Celexa), escitalopram (Lexapro)citalopram (Celexa), escitalopram (Lexapro)

Side Effects

• Anxiety

• Agitation

• Akathisia

• Nausea

• Insomnia

• Sexual dysfunction (anorgasmia/impotence)

Patient Teaching

• Take in the morning

• Take with food

• Propanolol given for akathisia

TCA Antidepressant Drugsimipramine (Tofranil), desipramine (Norpramin), imipramine (Tofranil), desipramine (Norpramin), amitriptyline (Elavil), doxepin (Sinequan), clomipramine amitriptyline (Elavil), doxepin (Sinequan), clomipramine (Anafranil)(Anafranil)

TCA Antidepressant Drugsimipramine (Tofranil), desipramine (Norpramin), imipramine (Tofranil), desipramine (Norpramin), amitriptyline (Elavil), doxepin (Sinequan), clomipramine amitriptyline (Elavil), doxepin (Sinequan), clomipramine (Anafranil)(Anafranil)

Side Effects

• Anticholinergic (blurred vision, urinary retention, dry mouth, constipation)

• Orthostatic hypotension

• Sedation

• Weight gain

• Tachycardia

• Sexual dysfunction

Patient Teaching

• Taking in the evening

• Using caution when driving

MAOI Antidepressant Drugsphenelzine (Nardil), tranylcypromine (Parnate), phenelzine (Nardil), tranylcypromine (Parnate), isocarboxazid (Marplan)isocarboxazid (Marplan)

MAOI Antidepressant Drugsphenelzine (Nardil), tranylcypromine (Parnate), phenelzine (Nardil), tranylcypromine (Parnate), isocarboxazid (Marplan)isocarboxazid (Marplan)

Side Effects

• Sedation

• Insomnia

• Weight gain

• Dry mouth

• Orthostatic hypotension

• Sexual dysfunction

• Hypertensive crisis with excessive tyramine or sympathomimetic drugs

Patient Teaching

• Following tyramine-free diet (avoid aged cheeses, aged meats, beer and wine, sauerkraut, soy)

• Avoiding sympathomimetic drugs

• Using caution when driving

Mood Stabilizing Drugslithium; anticonvulsant medications (carbamazepine lithium; anticonvulsant medications (carbamazepine (Tegretol), valproic acid (Depakote), lamotrigine (Tegretol), valproic acid (Depakote), lamotrigine (Lamictal), gabapentin (Neurontin)(Lamictal), gabapentin (Neurontin)

Mood Stabilizing Drugslithium; anticonvulsant medications (carbamazepine lithium; anticonvulsant medications (carbamazepine (Tegretol), valproic acid (Depakote), lamotrigine (Tegretol), valproic acid (Depakote), lamotrigine (Lamictal), gabapentin (Neurontin)(Lamictal), gabapentin (Neurontin)

Uses:

Bipolar disorder

Action:

Act on the neurotransmitters of the brain

Mood-Stabilizing DrugsMood-Stabilizing Drugs

Side Effects (Lithium)

• Nausea

• Diarrhea

• Anorexia

• Fine hand tremor

• Polydipsia

• Polyuria

• Fatigue

• Weight gain

• Acne

Patient Teaching (Lithium)

• Taking with food

• Having monthly blood levels drawn 12 hours after last dose (maintain therapeutic levels between 0.5–1.5 mEq/L)

Antianxiety Drugsbbenzodiazepines; buspirone (BuSpar)enzodiazepines; buspirone (BuSpar)Antianxiety Drugsbbenzodiazepines; buspirone (BuSpar)enzodiazepines; buspirone (BuSpar)

Uses:

Anxiety disorders, insomnia, OCD, depression, PTSD, alcohol withdrawal

Action:

Moderate the actions of GABA

Antianxiety DrugsAntianxiety Drugs

Side Effects

• Tolerance and dependence

• Drowsiness

• Sedation

• Poor concentration

• Impaired memory

• Clouded sensorium

Patient Teaching

• Using caution during driving due to slower reflexes and response time

• Never discontinuingabruptly aswithdrawalcan be fatal

• Avoiding alcohol

Stimulant Drugsmethylphenidate (Ritalin), pemoline (Cylert), methylphenidate (Ritalin), pemoline (Cylert), dextroamphetaminedextroamphetamine

Stimulant Drugsmethylphenidate (Ritalin), pemoline (Cylert), methylphenidate (Ritalin), pemoline (Cylert), dextroamphetaminedextroamphetamine

Uses:

ADHD, residual ADD in adults, and narcolepsy

Action:

Cause release of neurotransmitters

Stimulant DrugsStimulant Drugs

Side Effects

• Anorexia

• Weight loss

• Nausea

• Irritability

Patient Teaching

• Avoiding caffeine, sugar, and chocolate

• Taking after meals

• Long-term use can cause dependency

DisulfiramAntabuseAntabuseDisulfiramAntabuseAntabuse

Uses:

Aversion therapy for treatment of alcoholism

Action:

Causes an adverse reaction when alcohol is ingested

DisulfiramDisulfiram

Side Effects

• Fatigue

• Drowsiness

• Halitosis

• Tremor

• Impotence

Patient Teaching

• Avoiding alcohol (including products such as shaving cream, aftershave, cologne, many OTC medications)

• Family should never administer without the person's knowledge

Cultural ConsiderationsCultural Considerations

Ethnic backgrounds influence responses to some psychotropic medications:

• African Americans respond more rapidly to antipsychotic and tricyclic antidepressant medications than do whites and have a greater risk of side effects

• Asians metabolize antipsychotic and tricyclic antidepressants more slowly, requiring lower doses to produce the same effects

• Hispanics require lower doses of antidepressants than whites to achieve desired effects

• Asians and African Americans require lower doses of lithium than whites to produce desired effects

Self-Awareness IssuesSelf-Awareness Issues

Viewing chronic mental illness as having remissions and exacerbations, just as chronic physical illnesses do

 Remaining open to new ideas that may lead to future breakthroughs

 Understanding that medication noncompliance is often part of the illness, not willful misbehavior