Biopsychology chapter 18: Psychiatric Disorders

Cause of psychiatric disorders

Disruptions in brain systems governing emotion, cognition, and behavior.

meaning of schizophrenia

Splitting of psychic functions; a breakdown in the integration of emotion, thought, and action.

Core Symptoms of Schizophrenia

Delusions, hallucinations, inappropriate affect, incoherent thought, odd behavior, alogia, and anhedonia.

positive symptoms of schizophrenia

Symptoms that are present that should not be, such as hallucinations and delusions.

negative symptoms of schizophrenia

Loss of normal functions, such as flat affect and social withdrawal.

genetic evidence for schizophrenia

Higher concordance rates in monozygotic twins and increased risk with genetic relatedness.

neurodevelopmental hypothesis of schizophrenia

The disorder arises from abnormal brain development, with early insults remaining silent until adolescence.

first antipsychotic drug

Chlorpromazine; it reduced agitation.

Dopamine Theory of Schizophrenia

Hyperactivity of dopaminergic transmission contributes to schizophrenia, particularly positive symptoms.

mesolimbic and mesocortical pathways

Mesolimbic DA overactivity is linked to positive symptoms, while mesocortical DA underactivity is linked to negative and cognitive symptoms.

limitation of the dopamine theory of schizophrenia

Clozapine, an atypical antipsychotic, has minimal D2 binding yet is highly effective.

conventional D2 blockers

Block positive symptoms of schizophrenia.

affective disorders

Disturbances in mood and emotional regulation.

Alogia

Reduced quantity or quality of speech.

Anhedonia

Loss of pleasure or interest.

Avolition

Lack of motivation.

Depression

A mental health disorder characterized by persistent depressed mood or loss of interest for ≥ 2 weeks, leading to significant impairment in daily functioning.

mania and depression

Mania is characterized by excessive excitement and symptoms such as overconfidence, impulsivity, distractibility, high energy, hypersexuality, and decreased need for sleep, while depression involves low mood and loss of interest.

Bipolar Affective Disorder

A mental health disorder affecting approximately 1% of the population, characterized by alternating episodes of depression and mania.

Unipolar Depression?

A type of depression affecting up to 10% of the population, more common in females, which can be reactive (triggered by stressors) or endogenous (no identifiable cause).

Diathesis-Stress Model

A model suggesting that genetic vulnerability combined with early stress leads to a hypersensitive stress response, resulting in depression.

Monoamine Oxidase Inhibitors (MAOIs)

A class of antidepressants that prevent the breakdown of monoamines, initially developed for tuberculosis.

'cheese effect' related to MAOIs

MAO inhibition leads to tyramine accumulation, which can cause dangerous hypertension and increase stroke risk.

Tricyclic Antidepressants

Antidepressants like Imipramine and Amitriptyline that block the reuptake of serotonin and norepinephrine, but also have side effects like irregular heart rate and sedation.

Selective Serotonin Reuptake Inhibitors (SSRIs)

A class of antidepressants, including Fluoxetine and Zoloft, that selectively block serotonin reuptake with fewer cardiovascular side effects.

Monoamine Theory of Depression

suggests that depression results from reduced synaptic availability of monoamines like serotonin, norepinephrine, and dopamine.

neuropathology of depression

Hippocampal volume reduction and prefrontal cortex dysfunction, which affect emotional regulation.

Neuroplasticity Hypothesis

It posits that depression reflects impaired synaptic plasticity, with antidepressants potentially restoring plasticity via brain-derived neurotrophic factor (BDNF).

Lithium

A mood stabilizer used to treat bipolar disorder, preventing transitions between mania and depression.

Anxiety Disorders

Dysregulation of fear circuits, leading to excessive, persistent anxiety that interferes with daily functioning.

anxiety and anxiety disorder

Anxiety is a normal response to threat, while anxiety disorder involves excessive anxiety disproportionate to triggers.

Generalized Anxiety Disorder (GAD)

A condition characterized by chronic, diffuse, 'free-floating' anxiety not linked to specific situations.

Panic Disorder

Panic attacks that include palpitations, shortness of breath, chest pain, dizziness, and fear of dying or losing control.

Obsessive-Compulsive Disorder (OCD)

A disorder characterized by intrusive, repetitive thoughts (obsessions) and repetitive behaviors (compulsions) that reduce anxiety.

Post-Traumatic Stress Disorder (PTSD)

A condition involving persistent distress after experiencing extreme stress, with biological factors such as genetic vulnerability.

Benzodiazepines

Medications like Librium and Xanax that act as anxiolytics, enhancing the inhibitory effects of GABA but are highly addictive.

Role of the amygdala in anxiety disorders

The amygdala is involved in threat detection and is hyperactive during fear exposure, contributing to anxiety disorders.

Tourette Syndrome

A disorder characterized by motor and vocal tics, including coprolalia (involuntary obscene speech) and echolalia (repetition of others' words).