Chapter 18 Neurobiology of Schizophrenia, Mood Disorders, and Anxiety
Schizophrenia
It is characterized by “thought
disorders” which are defined as a
“break in reality or a splitting of
the cognitive from the emotional
side of one’s personality”.
Schizophrenia characteristics:
-affects 1% of the world’s population,
-behaviors include “incoherent speech, delusions, or hallucinations,
-psychotic episode may include positive symptoms: (hallucinations, delusions, positive
formal thought disorder or bizarre behavior),
-or negative symptoms (affective flattening, alogia, anhedonia-asociality, attention,
avolition-apathy),
-presents in the late teens or early 20’s,
-origin thought to be contributed to neurodevelopmental defects during fetal life.
Neuroanatomic and Functional Abnormalities:
-enlarged lateral and third ventricles and the widening of fissures and sulci in the frontal
cortex of the brain,
-the dorsolateral prefrontal cortex (DLPFC) is hypoactive, with decreased blood flow
and decreased glutamic acid decarboxylase (GABA),
-positive symptoms are contributed to the hypersecretion of mesolimbic dopamine,
-negative symptoms are contributed to an abnormal elevation in dopaminergic
transmission,
-antipsychotic drugs block dopamine and serotonin receptors; pyschosocial is also used
as an adjunctive therapy.
Mood Disorders
Mood disorders are defined as “a
sustained emotional state as opposed to
brief emotional feelings, which are
called affective states. When emotional
states such as euphoria (mania) and
depression are maintained and become
predominant, the individual may be
diagnosed with a mood disorder.”
Major depression (unipolar) characteristics:
-most common disorder,
-afflicted are unable to experience pleasure and have no outside interests,
-females have an x2 risk than males,
-25% of those with major depression will have an associated manic episode,
-recurrent patterns of manic/depression is called “bipolar disorder”,
-genetic basis exist for development of moos disorders,
-environmental factors play a role in depression,
-depression occurs with a deficit in brain monoamines: norepinephrine, and serotonin,
-mania results from elevated concentrations of monoamines,
-thyroid and growth hormone abnormalities are found in depression,
-structurally smaller frontal lobes and limbic systems,
-characterized by “unremitting feelings of sadness and despair, insomnia, loss of appetite
and body weight, and reduced interest in sex.”
-associated thoughts of suicide and risks thereof are increased.
Manic depression characteristics:
-elevated levels of euphoria and self-esteem,
-associated feelings of grandiosity,
-associated traits of restlessness and irritability,
-easily distracted,
-hallucinations and delusions may manifest.
Pharmacological treatments:
Unipolar depression: monoamine oxidase inhibitors, tricyclic antidepressants, and
selective serotonin reuptake inhibitors.
Manic and bipolar: lithium or mood stabilizers.
Electroconvulsive therapy may be used for those not responding to pharmacotherapy.
Panic disorder: “Characterized by
intense autonomic arousal that
involves a wide variety of
symptoms”
Symptoms: lightheadedness, racing heart, difficulty breathing, chest discomfort,
sweating, weakness, chills and hot flashes.
Treatments:
-behavioral therapy and antidepressant medication,
-breathing and biofeedback techniques are learned,
-benzodiazepines prescribed as adjunctive therapy.
Generalized Anxiety Disorder: characterized by “excessive and persistent worries…
about life, marital relationships, job performance, health, money, or social status.”
Treatment:
-serotonin/norepinephrine reuptake inhibitors,
-behavioral therapy,
-relaxation thechniques.
Posttraumitic stress disorders: produced by “ exposure to terrifying or life-threatening
events”
Characteristics:
-most susceptible are those with a history of mental illness, depression, or weak social
skills,
-traumatic event is re-experienced in thoughts and dreams,
-triggered by cues,
-individuals may avoid associated stimuli,
-results in difficulty sleeping, decreased concentration, and hypervigilance,
-brain regions involved prefrontal cortex, hippocampus, and amygdale.
Treatment:
-pschycotherapy,
-selective serotonin reuptake inhibitors,
-antidepressants.
Obsessive-compulsive disorder:
“Repetitive, intrusive thoughts and/or
compulsions…that are irrational, impair
normal functioning, and may cause
marked distress. Obsessions may involve
a preoccupation with contamination,
doubting, religious or sexual themes, or
a belief that a specific outcome will
occur if a specific act is not
performed.”
Characteristics:
-thoughts contributed to orbitofrontal and anterior cortical hyperactivity,
-serotonin agonists exacerbate symptoms.
Treatments:
-cognitive-behavioral therapy,
-selective serotonin reuptake inhibitors,
Reference:
McCance, K.L. & Huether, S. E. (2006) Pathophysiology: the biologic basis for disease
in adults and children. Mosby, St. Louis.
Organized Chaos website for celebrity information. Accessed at:
http://www.ocfoundation.org/organizedchaos/articles/Organized-Chaos-
V004/Organized-Chaos-V004_09.php