Brain Anatomy and Function

• The brain consists of the cerebrum, cerebellum, brain stem, and limbic system.

Cerebrum

• The cerebrum is divided into left and right hemispheres.

Left Hemisphere

• Controls the right side of the body.
• Center for logical reasoning and analytic functions like reading, writing, and mathematical tasks.

Right Hemisphere

• Controls the left side of the body.
• Center for creative thinking, intuition, and artistic abilities.
• Cerebral hemispheres are divided into four lobes.

Frontal Lobe

• Controls organization of thought, body movement, memories, emotions, and moral behavior.

Parietal Lobe

• Interprets taste and touch sensations.
• Assists in spatial orientation.

Temporal Lobe

• Centers for smell and hearing senses.
• Centers for memory and emotional expression.

Occipital Lobe

• Assists in coordinating language generation and visual interpretation.

Neurotransmitters

• 100 billion brain cells from neuron groups arrange in networks.
• Neurons communicate information by sending electrochemical messages through neurotransmission.
• Neurotransmitters are chemical substances aiding information transmission throughout the body.
• Neurotransmitters play a role in psychiatric illnesses, actions, and side effects of psychotropic drugs.

Dopamine

• Involved in complex movement control, motivation, cognition, and emotional response regulation.
• Gives feelings of pleasure and satisfaction.
• Decreased levels can cause disorders:
• ADHD disrupting emotional response handling
• Parkinson's disease
• Restlessness
• Leg Syndrome

Norepinephrine and Epinephrine

• Norepinephrine helps in attention, learning, and memory.
• Regulates sleep and wakefulness, and mood.
• Epinephrine controls the fight or flight response in the peripheral nervous system.
• Excess norepinephrine may cause several anxiety disorders.
• Deficits may contribute to memory loss, social withdrawal, and depression.

Serotonin

• Controls food intake, sleep and wakefulness, temperature regulation, pain control, sexual behavior, and emotion regulation.
• Plays a role in anxiety, mood disorders, and schizophrenia.

Histamine

• Connected to melatonin, they work together to control the sleep-wake cycle.
• Involved in peripheral allergic responses, gastric secretion control, cardiac stimulation, and alertness.
• Diphenhydramine can cause drowsiness
• Off-label use is as a sedative effect

Acetylcholine

• Involved in learning, intellectual function, memory, and involuntary muscle movements.
• Affects the sleep-wake cycle and signals muscles to become active.
• Decreased levels may cause Alzheimer’s disease
• Decreased levels may cause difficulty organizing things
• Decreased levels in acetylcholine receptors may cause myasthenia gravis.

Glutamate

• Excitatory neurotransmitter.
• Involved in learning, memory, and mood regulation.
• Increased levels may cause major neurotoxic effects, potentially neuron death.

Gamma-Aminobutyric Acid (GABA)

• Inhibitory neurotransmitter.
• Calming, slows down brain; blocks specific signals from firing up.
• Modulates other neurotransmitter systems rather than providing a direct stimulus.

Brain Imaging Techniques

Computed Tomography (CT)

• Also called computed axial tomography.
• Precise X-ray beam takes cross-sectional images (slices) layer by layer.
• A computer reconstructs images on a monitor and stores them on magnetic tape or film.
• Can visualize brain's soft tissues.
• Used to diagnose primary tumors, metastases, and effusions.
• Determines ventricle size in the brain.

Magnetic Resonance Imaging (MRI)

• Energy field created with a huge magnet and radio waves, converted to an image.
• Produces more tissue detail and contrast than CT.
• Shows blood flow patterns and tissue changes like edema.

Positron Emission Tomography (PET) & Single-Photon Emission Computed Tomography (SPECT)

• Used to examine brain function.
• Radioactive substances are injected into the blood.
• The flow of substances is monitored as the client performs cognitive activities.
• PET uses two photons simultaneously with SPECT using a single photon.

Limitations of Brain Imaging Techniques

• PET and SPECT use substances limits the number of tests a person can undergo.
• There is the risk that the client will have an allergic reaction to the substances.
• Some clients may find receiving intravenous doses of radioactive material frightening or unacceptable.
• Imaging equipment is expensive to purchase and maintain, so availability can be limited.
• Some intolerant persons because of fear or claustrophobia.
• Researchers are finding that many of the changes in disorders such as schizophrenia are at the molecular and chemical levels and cannot be detected with current imaging techniques.

Neurobiologic Causes of Mental Illness

• Genetics and Heredity.
• Stress and the Immune System (Psychoimmunology).
• Infection as a Possible Cause.

Psychopharmacology

• Efficacy: The maximal therapeutic effect a drug can achieve.
• Potency: The amount of drug needed to achieve that maximum effect. Low potency drugs require high dosages to achieve efficacy, while high potency drugs achieve efficacy at lower dosages.
• Half-life: The time it takes for half of the drug to be removed from the bloodstream.
• Off-label use: A drug effective for a disease differing from the one in original testing and FDA approval.
• Package inserts must have a highlighted black box contains about the serious or life-threatening side effects.

Principles that guide pharmacologic treatment

• Medication selected based on effect on client's target symptoms, such as delusional thinking, panic attacks, or hallucinations.
• Many psychotropic drugs given in adequate dosages for full effects.
• Medication dosage adjusted to the lowest effective dosage.
• Older adults require lower dosages of medications than do younger clients.
• Psychotropic medications decreased gradually (tapering) rather than abruptly to avoid rebound, recurrence, or withdrawal.
• Follow-up care is essential.
• Compliance is enhanced when the regimen is as simple as possible.

Classification of Psychopharmacologic Drugs

• Antipsychotics
• Antidepressants
• Mood stabilizers
• Anti-anxiety Drugs (Anxiolytics)
• Stimulants
• Disulfiram (Antabuse)

Antipsychotic Drugs

• Used to treat psychosis.
• Manic phase of bipolar disorder.

Mechanism of Action

• Alters brain chemistry to reduce psychotic symptoms.

Conventional or First-Generation Antipsychotics

• Chlorpromazine (Thorazine)
• Perphenazine (Trilafon)
• Fluphenazine (Prolixin)
• Thioridazine (Mellaril)
• Mesoridazine (Serentil)
• Trifluoperazine (Stelazine)
• Thiothixene (Navane)
• Haloperidol (Haldol)

Atypical or Second-Generation Antipsychotics

• Clozapine (Clozaril)
• Fazaclo (clozapine)
• Risperidone (Risperdal)
• Olanzapine (Zyprexa)
• Quetiapine (Seroquel)
• Ziprasidone (Geodon)
• Paliperidone (Invega)
• Iloperidone (Fanapt)
• Asenapine (Saphris)
• Lurasidone (Latuda)

Third-Generation Antipsychotics

• Aripiprazole (Abilify)
• Cariprazine (Vraylar)
• Brexpiprazole (Rexulti)

Side Effects

Extrapyramidal Side Effects

• Serious neurologic symptoms. Include:

Dystonia

• Acute muscular rigidity and cramping.
• Most likely to occur in the 1st week of treatment.
• Can Cause:
• Torticollis (twisted head and neck)
• Opisthotonus (tightness)
• Oculogyric crisis (eyes rolled back in a locked position)

Pseudoparkinsonism

• Imitates the s/sx and appearance of Parkinson's.
• May Cause
  • Stiffness
  • Shuffling gait
  • Rigidity
  • Stooped posture
  • Decreased arm swing
  • Masklike facies

Akathisia

• Intense need to move.

Neuroleptic Malignant Syndrome

• A potentially fatal idiosyncratic reaction.

Tardive Dyskinesia

• Syndrome of permanent involuntary movements
• The long-term use of conventional antipsychotic drugs

Anticholinergic Side Effects

• Occurs with antipsychotics.
• Includes orthostatic hypotension, dry mouth, constipation, urinary hesitance/retention, blurred vision, dry eyes, photophobia, nasal congestion, and decreased memory.
• Side effects usually decrease within 3-4 weeks but do not remit entirely.

Antidepressant Drugs

• Preferred drugs for clients at high risk for suicide.
• Suicide is always top consideration when treating depression.

Mechanism of Action

• The precise mechanism is unknown, but much is known about action on the CNS.
• The major interaction is with the monoamine neurotransmitter systems in the brain
• Groups:
• Selective serotonin Reuptake Inhibitors (SSRIs)
• Cyclic Antidepressants
• Monoamine Oxidase Inhibitors (MAOIs)

Selective Serotonin Reuptake Inhibitors

• Fluoxetine (Prozac)
• Fluvoxamine (Luvox)
• Paroxetine (Paxil)
• Sertraline (Zoloft)
• Citalopram (Celexa)
• Escitalopram (Lexapro)

Cyclic Compounds

• Imipramine (Tofranil)
• Desipramine (Norpramin)
• Amitriptyline (Elavil)
• Nortriptyline (Pamelor)
• Doxepin (Sinequan)
• Trimipramine (Surmontil)
• Protriptyline (Vivactil)

Other Compounds

• Bupropion (Wellbutrin)
• Venlafaxine (Effexor)
• Desvenlafaxine (Pristiq)
• Trazodone (Desyrel)
• Nefazodone (Serzone)
• Duloxetine (Cymbalta)
• Vilazodone (Viibryd)

Monoamine Oxidase Inhibitors

• Phenelzine (Nardil)
• Tranylcypromine (Parnate)
• Isocarboxazid (Marplan)

Side Effects of SSRIs

• Anxiety, agitation, akathisia, nausea, insomnia, and sexual dysfunction.

Side Effects of Cyclic Antidepressants

• Dry mouth, constipation, urinary hesitancy/retention, dry nasal passages, and blurred vision, orthostatic hypotension, sedation, weight gain, and tachycardia.

Side Effects of MAOIs

• Daytime sedation, insomnia, weight gain, dry mouth, orthostatic hypotension, and sexual dysfunction.
• When taking, avoid foods with TYRAMINE, since it tightens the blood vessels leading to increase in BP.

Mood-Stabilizing Drugs

• Used in bipolar disorder treatment
• Prevent/minimize highs and lows while treating acute mania episodes.
• Lithium is the most established mood stabilizer.
• Anticonvulsant drugs are effective mood stabilizers.
• Other anticonvulsants also used for mood stabilization.

Side Effects

• Common side effects of lithium: mild nausea or diarrhea, anorexia, fine hand tremor, polydipsia, polyuria, metallic taste, fatigue/lethargy.
• Toxic effects: severe diarrhea, vomiting, drowsiness, muscle weakness, and lack of coordination.
• Carbamazepine and valproic acid side effects: drowsiness, sedation, dry mouth, and blurred vision.

Antianxiety Drugs (Anxiolytics)

• Treat anxiety and anxiety disorders, insomnia, obsessive-compulsive disorder (OCD), depression, post-traumatic stress disorder, and alcohol withdrawal.
• Benzodiazepines are the most effective.
• Benzodiazepines prescribed for their anticonvulsant and muscle relaxant effects.

Side Effects

• those associated with CNS depression: drowsiness, sedation, poor coordination, and impaired memory or clouded sensorium.

Stimulants

• Stimulant drugs, specifically amphetamines, were first used for their pronounced effects on CNS stimulation.
• Today, the primary stimulant use is for:
  • ADHD in children and adolescents
  • Residual attention-deficit disorder in adults
  • Narcolepsy

Drugs Used to Treat Attention-Deficit/Hyperactivity Disorder

• Methylphenidate (Ritalin)
• Dextroamphetamine (Dexedrine)
• Amphetamine (Adderall)
• Pemoline (Cylert)
• Atomoxetine (Strattera)

Side Effects

• Common side effects: anorexia, weight loss, nausea, and irritability.

Disulfiram (Antabuse)

• Sensitizing agent that causes an adverse reaction when mixed with alcohol in the body.
• Deterrent to drinking alcohol in treated persons for alcoholism.
• Useful for motivated persons to abstain from drinking and who are not impulsive.