NR 507 Patho CH. 19 Neurobiology of Schizophrenia, Mood Disorders, Anxiety Disorders, Posttraumatic Stress Disorder, and Obsessive-Compulsive Disorder questions and answers

Schizophrenia

Schizophrenia is characterized by thought disorders that reflect discontinuity between emotion, thought, behavior, and cognition.

Categories of symptoms in schizophrenia

Symptoms are classified into positive, negative, and cognitive categories.

Positive symptoms of schizophrenia

Positive symptoms include hallucinations, delusions, formal thought disorder, and bizarre behavior.

Negative symptoms of schizophrenia

Negative symptoms include flattened affect, alogia (poverty of speech), anhedonia (lack of pleasure), attention deficits, and apathy.

Cognitive symptoms of schizophrenia

Cognitive symptoms include the inability to perform daily tasks requiring attention and planning.

Factors contributing to schizophrenia

Schizophrenia has a strong genetic predisposition, but environmental factors (e.g., viral infection, nutritional deficiencies, prenatal birth complications, urban upbringing) can alter brain structure and function.

Structural brain abnormalities in schizophrenia

Brain imaging studies show enlargement of the cerebral ventricles, widening of fissures and sulci in the frontal cortex, and a reduction in the volumes of the thalamus and temporal lobe.

Frontal lobe changes in schizophrenia

The frontal lobe shows progressive loss in volume and worsening negative symptoms, even with antipsychotic medication. Blood flow and metabolism are reduced in the dorsolateral prefrontal cortex.

Neurochemical abnormalities in schizophrenia

Neurochemical abnormalities in dopamine and glutamate systems are found in schizophrenia.

First-generation antipsychotics

First-generation antipsychotics block the dopamine D2 receptor.

Second-generation antipsychotics

Second-generation (atypical) antipsychotics block not only D2 receptors but also dopamine, serotonin, and other neurotransmitter receptors.

Effectiveness of antipsychotic medications

Antipsychotic medications are not always effective in treating the negative symptoms of schizophrenia.

Role of talk therapies in schizophrenia treatment

Talk therapies are used to improve medication adherence and encourage coping strategies.

Common mood disorders

Major depression and bipolar disorder.

Characteristics of major depression

Major depression is characterized by an intense and sustained unpleasant state of sadness and hopelessness.

Characteristics of bipolar disorder

Bipolar disorder is characterized by recurrent patterns of depression and mania, with mania marked by extreme levels of energy and euphoria.

Environmental factors contributing to depression

Environmental triggers such as psychosocial stress appear to facilitate the onset of depression in individuals with a genetic vulnerability.

Brain neurotransmission linked to depression and mania

A reduction in brain monoamine neurotransmission is linked to depression, while elevated monoamine levels are associated with mania.

Effect of uncontrollable stress on depression

Stress elevates cortisol secretion, which increases proinflammatory cytokines and the risk of developing depression. Abnormalities in thyroid hormones are also found in depression.

Stress-induced depression and BDNF

Stress-induced depression is accompanied by deficits in BDNF and neurogenesis in the hippocampus. In animal models, antidepressant treatment can reverse these deficits.

Frontal lobe and limbic system in mood disorders

The frontal lobe and limbic system volumes are reduced, with altered blood flow in prefrontal and limbic brain regions, including the amygdala, which is implicated in emotional behavior.

Medications for depression

Medications include monoamine oxidase inhibitors (MAOIs), tricyclic antidepressants (TCAs), selective serotonin reuptake inhibitors (SSRIs), and atypical antipsychotics.

Pharmacological treatment of bipolar disorder

Manic and bipolar individuals are treated with lithium, mood stabilizers, and atypical antipsychotic medications.

Treatments for severely depressed or manic individuals

Severely depressed and manic individuals may be administered electroconvulsive therapy (ECT), and deep brain stimulation is a promising treatment for intractable depression.

Anxiety Disorder Development

An individual may develop an anxiety disorder when normal fear and anxiety persist and become uncontrollable.

Examples of Anxiety Disorders

Panic disorder (PD), social anxiety disorder (SAD), and generalized anxiety disorder (GAD) are examples of anxiety disorders that require medical attention.

Panic Disorder Characteristics

Panic disorder consists of panic attacks with intense autonomic arousal, symptoms like lightheadedness, tachycardia, difficulty breathing, and heightened fear and anxiety that continue between attacks.

Panic-Prone Individuals and Amygdala

Panic-prone people are sensitive to pH alterations in the amygdala, which modulates fear, potentially exacerbating panic symptoms when activated.

Benzodiazepine Receptors in Panic Disorder

A reduction in benzodiazepine receptor binding in brain regions like the hippocampus, insula, and prefrontal cortex may contribute to panic disorder.

Panic Disorder Treatment

Panic disorder is treated with cognitive-behavioral therapy (CBT) and antidepressants like TCAs and SSRIs. Benzodiazepines (BZs) may be used as adjunct therapy for nonresponsive patients.

Social Anxiety Disorder (SAD)

Social anxiety disorder is characterized by fear and avoidance of social situations, often emerging in adolescence, with a fear of being evaluated, embarrassed, or rejected by others.

Brain Connection Abnormalities in SAD

Neuroimaging studies reveal abnormal connections between the prefrontal cortex and the amygdala in individuals with social anxiety disorder.

Oxytocin's Role in SAD

Oxytocin promotes social behavior, empathy, and trust. In SAD, OXT secretion is reduced, and alterations in the OXT receptor gene are found, suggesting OXT plays a role in the disorder.

Treatments for Social Anxiety Disorder

Treatment for SAD may involve SSRIs, serotonin-norepinephrine reuptake inhibitors (SNRIs), or cognitive therapies.

Generalized Anxiety Disorder (GAD) Characteristics

GAD is characterized by excessive and persistent worry about life events, with symptoms such as motor disturbances, irritability, and fatigue, often linked to psychosocial stress and sometimes depression.

Brain Areas Implicated in GAD

Changes in the cingulate cortex and amygdala may contribute to anticipatory anxiety and attentional bias to threats in people with GAD.

GAD Treatment

Treatment for GAD usually involves a combination of behavioral therapy and medications, particularly 5-HT/norepinephrine reuptake inhibitors.

Post-traumatic Stress Disorder (PTSD)

PTSD develops after exposure to a life-threatening or traumatic experience, leading to recurring thoughts, flashbacks, and nightmares of the event.

Brain areas altered in PTSD

Structural and/or functional alterations in the amygdala, prefrontal cortex, and hippocampus contribute to dysfunction in the emotional fear memory system in PTSD.

Chronic PTSD treatment

Chronic PTSD treatment may involve psychotherapy and SSRI pharmacotherapy. Esketamine, a recently FDA-approved drug for treatment-resistant PTSD, is also promising in rapidly alleviating symptoms.

Obsessive-Compulsive Disorder (OCD)

OCD is a chronic illness characterized by irrational obsessions and ritualized acts that impair normal functioning and cause severe distress.

Impact of OCD on daily life

OCD is time-consuming and significantly impairs social relationships, job performance, and academic success due to the compulsive nature of the disorder.

Common examples of obsessions in OCD

Common obsessions in OCD include preoccupation with doubting, religious or sexual themes, or the belief that a negative outcome will occur if specific acts are not performed.

Brain circuit involved in OCD

The pathophysiologic brain circuit involved in OCD includes the anterior thalamus, orbitofrontal cortex, dorsal anterior cingulate cortex, and basal ganglia subregions (caudate and putamen).

Treatment for OCD

OCD requires long-term treatment, including psychotherapy and pharmacotherapy. In treatment-resistant cases, electroconvulsive therapy (ECT) or transcranial magnetic stimulation (TMS) may be used. Severe OCD may require neurosurgery or deep brain stimulation (DBS).