Chapter 2:
Neurobiologic Theories and
Psychopharmacology
Central Nervous System
 Brain (see Figs. 2.1 and 2.2)
o Cerebrum
o Cerebellum
o Brain stem
o Limbic system
 Nerves that control voluntary acts (neurotransmitters)
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Cerebrum
 Two hemispheres
 Four lobes:
o Frontal lobe (thought, body movement, memories,
emotions, moral behavior)
o Parietal lobe (taste, touch, spatial orientation)
o Temporal lobe (smell, hearing, memory, emotional
expression)
o Occipital lobe (language, visual interpretation such as
depth perception)
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Cerebellum
 Below cerebrum
 Center for coordination of movements and postural
adjustments
 Reception, integration of information from all body areas
to coordinate movement and posture
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Brain Stem
 Midbrain: reticular activating system (motor activity,
sleep, consciousness, awareness) and extrapyramidal
system
 Pons: primary motor pathway
 Medulla oblongata: vital centers for cardiac, respiratory
function
 Nuclei for cranial nerves III through XII
 Locus coeruleus: norepinephrine-producing neurons
(stress, anxiety, impulsive behavior)
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Limbic System
 Above brain stem
o Thalamus (activity, sensation, emotion)
o Hypothalamus (temperature regulation, appetite
control, endocrine function, sexual drive, impulsive
behavior)
o Hippocampus and amygdala (emotional arousal,
memory)
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Neurotransmitters #1
 Chemical substances to facilitate neurotransmission (see
Fig. 2.3)
 Important in right proportions to relay messages; studies
showing differences in brains of people with some mental
disorders (see Fig. 2.4)
 Play role in psychiatric illness and psychotropic
medications, including their actions and side effects
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1. Neurotransmitters #2
 Excitatory or inhibitory (see Table 2.1)
o Excitatory
 Dopamine: complex movements, motivation,
cognition, regulation of emotional response
 Norepinephrine: attention, learning, memory,
sleep, wakefulness, mood regulation
 Epinephrine: fight-or-flight response
 Glutamate: neurotoxic effects at high levels
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2. Neurotransmitters #3
 Excitatory or inhibitory (see Table 2.1) (cont.)
o Inhibitory
 Serotonin: food intake, sleep, wakefulness,
temperature regulation, pain control, sexual
behaviors, regulation of emotions
 GABA: major inhibitory neurotransmitter;
modulation of other neurotransmitters
o Excitatory or inhibitory
 Acetylcholine: sleep-and-wakefulness cycle;
signals muscles to become alert
 Histamine: neuromodulator
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1. Question #1
Is the following statement true or false?
 The cerebellum consists of four lobes.
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1. Answer to Question #1
False
 Rationale: The cerebrum consists of four lobes. The
cerebellum is located below the cerebrum.
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Brain Imaging Techniques
 Computed tomography (CT)
 Magnetic resonance imaging (MRI)
 Positron emission tomography (PET)
 Single-photon emission computed tomography (SPECT)
 Limitations
o Use of radioactive substances; expense of
equipment; client’s inability to tolerate technique
o Changes in disorders nondetectable with current
techniques
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Neurobiologic Causes
 Genetics and heredity: play role but not solely genetic
o Twin, adoption, and family studies are used.
 Psychoimmunology: compromised immune system
possibly contributing, especially in genetically at-risk
populations
 Infections: theories include viruses that alter human
genes, viruses during fetal development
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Nurse’s Role in Research and Education
 Ensure all clients and families are well informed
 Help distinguish between facts and hypotheses
 Explain if or how new research may affect client’s
treatment or prognosis
 Provide information and answer questions
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2. Question #2
Is the following statement true or false?
 Single-photon emission computed tomography (SPECT)
is considered the best type of brain imaging technique to
diagnose disease.
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2. Answer to Question #2
False
 Rationale: Single-photon emission computed tomography
(SPECT) is not considered the best type of brain imaging
used to diagnose disease. In fact, many of the changes
in the brain are not currently detectable with any of the
current techniques.
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Psychopharmacology #1
 Psychotropic drugs
 Efficacy (maximal therapeutic effect)
 Potency (amount of drug needed for maximum effect)
 Half-life
 Role of the FDA
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Psychopharmacology #2
 Off-label use (drug may be effective for treating a
disease different from one involved in original testing)
 Black box warning (serious or life-threatening side
effects)
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Principles of Psychopharmacology
 Effect on target symptoms
 Adequate dosage for sufficient time
 Lowest effective dose
 Lower doses for older adults
 Tapering rather than abrupt cessation to avoid rebound,
recurrence of symptoms, or withdrawal
 Follow-up care
 Simple regimen to increase compliance
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Antipsychotic Drugs #1
 Antipsychotic drugs (see Table 2.3)
o Conventional or first generation (e.g.,
chlorpromazine, fluphenazine, thioridazine,
haloperidol, loxapine)
o Atypical or second generation (e.g., clozapine,
risperidone, olanzapine)
o Third generation (dopamine system stabilizers; e.g.,
aripiprazole)
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Antipsychotic Drugs #2
 Use: treat symptoms of psychosis
 Mechanism of action: block dopamine receptors
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Antipsychotics: Side Effects #1
 Extrapyramidal symptoms (EPSs):
o Acute dystonia
 Torticollis, opisthotonus, oculogyric crisis
 Treatment: anticholinergic drugs or
diphenhydramine (see Table 2.4)
o Pseudoparkinsonism (stooped posture, masklike
facies, shuffling gait)
o Akathisia (restlessness, anxiety, agitation)
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1. Antipsychotics: Side Effects #2
 Neuroleptic malignant syndrome (NMS)
 Tardive dyskinesia (permanent involuntary movements)
 Anticholinergic side effects (e.g., dry mouth,
constipation, urinary hesitancy or retention)
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2. Antipsychotics: Side Effects #3
 Other side effects:
o Increased prolactin levels
o Weight gain (most likely with second-generation
agents, except ziprasidone)
o Metabolic syndrome
o Cardiovascular adverse effects
o Lengthening of QT interval (thioridazine, droperidol,
mesoridazine)
o Agranulocytosis (clozapine)
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Antipsychotics: Client Teaching
 Adherence to regimen
 Management of side effects
o Thirst/dry mouth (sugar-free candy, liquids)
o Constipation (dietary fiber, exercise)
o Sleepiness/drowsiness (safety measures)
 Actions for missed dose (dose if within 4 hours of usual
time)
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3. Question #3
 Which of the following drugs would be classified as a
conventional antipsychotic?
A. Clozapine
B. Risperidone
C. Fluphenazine
D. Aripiprazole
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3. Answer to Question #3
C. Fluphenazine
 Rationale: Fluphenazine is classified as a conventional
antipsychotic.
o Clozapine and risperidone are considered secondgeneration antipsychotics. Aripiprazole is considered
a third-generation antipsychotic.
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Antidepressants #1
 Use: major depressive illness, anxiety disorders,
depressed phase of bipolar disorder, psychotic
depression
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1. Antidepressants #2
 Four groups (see Table 2.5):
o Selective serotonin reuptake inhibitors (SSRIs)
o Cyclic compounds
o Other antidepressants
o Monoamine oxidase inhibitors
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2. Antidepressants #3
 Precise mechanism is not known.
 Major interaction is with monoamine neurotransmitter
systems, especially norepinephrine and serotonin.
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Antidepressants: Side Effects #1
 SSRIs
o Anxiety, agitation, akathisia, nausea, insomnia,
sexual dysfunction
o Weight gain
 Cyclic antidepressants
o Anticholinergic effects
o Orthostatic hypotension, sedation, weight gain,
tachycardia
o Sexual dysfunction
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1. Antidepressants: Side Effects #2
 MAOIs
o Daytime sedation, insomnia, weight gain, dry mouth,
orthostatic hypotension, sexual dysfunction
o Hypertensive crisis (with foods containing tyramine)
 Other antidepressants
o Sedation, headaches (nefazodone, trazodone)
o Loss of appetite, nausea, agitation, insomnia
(bupropion, venlafaxine)
o Priapism (trazodone)
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Antidepressants: Drug Interactions
 Serotonin syndrome
o MAOI + SSRI
o Agitation, sweating, fever, tachycardia, hypotension,
rigidity, hyperreflexia
o Coma, death (extreme reactions)
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Antidepressants: Client Teaching
 Time of dosage
o SSRI first thing in morning
o Cyclic compounds at night
 Actions for missed dose
o SSRI up to 8 hours after missed dose
o Cyclic within 3 hours of missed dose or omit the
day’s dose
 Safety measures
 Dietary restrictions with MAOIs (see Box 2.1)
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Mood-Stabilizing Drugs #1
 Lithium, some anticonvulsants (carbamazepine, valproic
acid; gabapentin, topiramate, oxcarbazepine, and
lamotrigine)
 Use: treatment of bipolar illness
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Mood-Stabilizing Drugs #2
 Mechanism of action
o Lithium normalizes reuptake of certain
neurotransmitters.
o Valproic acid and topiramate increase the levels of
GABA.
o Valproic acid and carbamazepine inhibit the kindling
process.
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Mood-Stabilizing Drugs: Side Effects #1
 Lithium
o Nausea, diarrhea, anorexia, fine hand tremor,
polydipsia, polyuria, metallic taste in the mouth,
fatigue, lethargy; weight gain, acne (later in therapy)
o Toxicity: severe diarrhea, vomiting, drowsiness,
muscle weakness, lack of coordination
 Carbamazepine and valproic acid: drowsiness, sedation,
dry mouth, blurred vision
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Mood-Stabilizing Drugs: Side Effects #2
 Carbamazepine: rash, orthostatic hypotension
 Valproic acid: weight gain, alopecia, hand tremor
 Topiramate: dizziness, sedation, weight loss
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Mood-Stabilizing Drugs: Client Teaching
 Periodic monitoring of blood levels
o 12 hours after last dose taken
 Taking medication with meals
 Safety measures
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4. Question #4
Is the following statement true or false?
 A client who takes an SSRI with an MAOI is at risk for a
hypertensive crisis.
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4. Answer to Question #4
False
 Rationale: A client who takes an SSRI with an MAOI is at
risk for serotonin syndrome.
o Hypertensive crisis can occur if the client is taking an
MAOI and ingests foods containing tyramine.
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Antianxiety Drugs
 Use: treatment of anxiety and anxiety disorders,
insomnia, OCD, depression, posttraumatic stress
disorder, alcohol withdrawal
 Benzodiazepines, buspirone (see Table 2.6)
 Mechanism of action
o Mediation of GABA (benzodiazepines)
o Partial agonist activity at serotonin receptors
(buspirone)
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Antianxiety Drugs: Side Effects
 Benzodiazepines
o Physical, psychological dependence
o CNS depression
o Hangover effect
o Tolerance
 Buspirone
o Dizziness, sedation, nausea, headache
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Antianxiety Drugs: Client Teaching
 Safety measures
 Avoidance of alcohol
 Avoidance of abrupt discontinuation
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Stimulants #1
 Amphetamines (methylphenidate, amphetamine,
dextroamphetamine)
 Use: treatment of ADHD in children and adolescents,
residual attention-deficit disorder in adults, narcolepsy
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Stimulants #2
 Mechanism of action
o Cause release of norepinephrine, dopamine,
serotonin presynaptically
o Block reuptake of neurotransmitters
 Dosage
o Divided doses; higher doses for narcolepsy in adults
o Doses for treating ADHD vary widely (see Table 2.7).
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Stimulants: Side Effects and Client Teaching
 Side effects
o Anorexia, weight loss, nausea, irritability
o Growth and weight suppression
 Client teaching
o Dose after meals
o Avoidance of caffeine, sugar, chocolate
o Proper storage out of reach of children
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Disulfiram #1
 Use: aversion therapy for alcoholism
 Mechanism of action: inhibition of enzyme involved with
alcohol metabolism
o Adverse reaction with alcohol ingestion
 Side effects: fatigue, drowsiness, halitosis, tremor,
impotence
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Disulfiram #2
 Drug interactions with phenytoin, isoniazid, warfarin,
barbiturates, long-acting benzodiazepines
 Client teaching: avoidance of alcohol, including common
products that may contain it
o Shaving cream, deodorant, OTC cough preparations
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5. Question #5
 Which of the following drugs would the nurse expect to
administer to a client with ADHD?
A. Disulfiram
B. Methylphenidate
C. Buspirone
D. Lithium
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5. Answer to Question #5
B. Methylphenidate
 Rationale: Methylphenidate is a stimulant used to treat
ADHD.
o Disulfiram is used to treat alcoholism. Buspirone is
used to treat depression. Lithium is used to treat
bipolar illness.
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Cultural Considerations #1
 More rapid response to antipsychotic medications and
tricyclic antidepressants for African Americans than white
people
o Higher risk of side effects
 Slower metabolism of antipsychotics and tricyclic
antidepressants for Asians than white people
o Lower doses to produce the same effects
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Cultural Considerations #2
 Increased frequency of herbal medicine use
o St. John’s Wort
o Kava
o Valerian
o Ginkgo biloba
 Increased risk for interactions with herbal medicine
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Self-Awareness Issues
 Clients and families need more than factual information;
they need simple and thorough explanations.
 View chronic mental illness as having remissions and
exacerbations, just as chronic physical illnesses do.
 Remain open to new ideas that may lead to future
breakthroughs.
 Understand that medication noncompliance is often part
of faulty thinking and reasoning related to the illness, not
willful misbehavior.
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