Psychiatric Disorders

Psychiatric Disorders
Chapter 15 PSY2301: Biological Foundations of Behavior

What Happens When the Brain Misbehaves?
Research on Brain and Behavioral Disorders Classifying and Treating Brain and Behavioral Disorders Understanding and Treating Neurological Disorders Understanding and Treating Psychiatric Disorders PSY2301: Biological Foundations of Behavior

PSY2301: Biological Foundations of Behavior
Mental Disorders Diagnostic and Statistical Manual of Mental Disorders-IV-TR Classes of mental Disorders Anxiety Disorders Mood Disorders Schizophrenia Dissociative and Somatoform Disorders Personality Disorders Eating Disorders Sexual Disorders Gender-identity disorders Childhood Disorders Substance-Related Disorders PSY2301: Biological Foundations of Behavior

Schizophrenia 7 in 1000 people will develop schizophrenia Symptoms: Positive: Delusions, Hallucinations, Disorganized thought and speech, Disorganized catatonic behavior Negative: affective flattening, alogia, avolition Diagnostic Criteria: Schizophrenia: At least 1 month of acute symptoms 2 or more: delusions, hallucinations, disorganized thought and speech, disorganized behavior, and negative symptoms, and at least 6 months of some symptoms Schizophreniform Disorder: lasting over 1 month, but less than 6 months. some symptoms PSY2301: Biological Foundations of Behavior

Schizophrenia Type I Schizophrenia Characterized predominately by positive symptoms likely due to a dopaminergic dysfunction and associated with acute onset, good prognosis, and a favorable response to neuroleptics Type II Schizophrenia Characterized by negative symptoms associated with chronic affliction, poor prognosis, poor response to neuroleptics, cognitive impairments, enlarged ventricles, and cortical atrophy, particularly in the frontal cortex Know these for exam. Type I is more typical and linked to dopaminergic dysfunction Type II, Large ventricle = some loss of neurons in the brain PSY2301: Biological Foundations of Behavior

Schizophrenia Delusions: Persecutory delusions Grandiose delusions Delusions of thought control Hallucinations: Auditory hallucinations Visual hallucinations Tactile hallucinations Somatic hallucinations Catatonia A group of disorganized behaviors that reflect the extreme lack of responsiveness to the outside world Most typical hallucinations are auditory PSY2301: Biological Foundations of Behavior

Schizophrenia Genes: No single genetic abnormality accounts for this complex disorder Increased risk for family members 48% concordance rate for identical twins, 17% for dizygotic twins Smoking marijuana could increase an individual to develop schizophrenia if they have the genetic predisposition PSY2301: Biological Foundations of Behavior

Schizophrenia Neuroanatomical Correlates Enlarged ventricles Reduction in white matter in the frontal lobes Reduced Brain Volume and Neuron density: Frontal, temporal, basal ganglia, limbic area (hippocampus and amygdala) Abnormalities in the auditory regions of the temporal lobes Abnormalities in Wernicke’s area Abnormal blood flow in the dorsolateral prefrontal cortex Abnormalities in the auditory regions of the temporal lobes may account for auditory hallucinations Abnormalities in Wernicke’s area may account for thought disorder Abnormal blood flow in the dorsolateral prefrontal cortex may account for deficits in executive functioning (Type II) PSY2301: Biological Foundations of Behavior

Schizophrenia Neurotransmitter Dysregulation Dopamine Theory Supporting Evidence Neuroleptics Dopamine agonists Evidence against Dopamine Theory: Neuroleptic response rate Dopamine Theory Supporting Evidence One of the first neurotransmitters to be implicated in schizophrenia Neuroleptics are dopamine antagonists Dopamine agonists can produce psychotic symptoms Higher number of D receptors Side Effects: motor symptoms Evidence against Dopamine Theory: Not everybody responds to drugs Even if Dopamine levels decrease after hours-days, symptoms take longer to subside PSY2301: Biological Foundations of Behavior

Schizophrenia Mesolimbic System: Emotion control High Dopamine levels D3 and D4 receptors Positive symptoms Serotonin Regulates dopamine neurons in the mesolimbic system Frontal Cortex Low dopamine levels (or structural abnormalities) Negative symptoms Mesolimbic connects to limbic and then hippocampus and is thought to affect emotion control and cause positive symptoms Frontal linked to type 2 and cause more negative symptoms PSY2301: Biological Foundations of Behavior

Mood Disorders Depression Mania Disordered mental state characterized by excessive euphoria, but mixed with agitation and irritation Bipolar disorder Mood disorder characterized by alternating periods of depression and mania PSY2301: Biological Foundations of Behavior

Mood Disorders: Major Depression
Symptoms: Emotional: sadness, depressed mood, anhedonia, irritability Physiological and behavioral: sleep disturbance, appetite disturbance, psychomotor retardation or agitation, catatonia, fatigue and loss of energy Cognitive: poor concentration and attention, indecisiveness, sense of worthlessness or guilt, poor self-esteem, hopelessness, suicidal thoughts, delusions and hallucinations with depressing themes Common: ~6% of adult population More common in women than in men Depression vs. dysthymia PSY2301: Biological Foundations of Behavior

Mood Disorders: Major Depression
Genetics: rates of bipolar and depressive disorders among first-degree relatives Twin studies Neurobiology Norepinephrine and Serotonin Genetics: 2-3 times higher rates of bipolar and depressive disorders among first-degree relatives Twin studies: 60% concordance rate among identical twins and 13% among dizygotic twins Neurobiology Antidepressant drugs act to increase levels of norepinephrine and serotonin There is little evidence, however, that low levels of these neurotransmitters cause depression Lowering levels of these neurotransmitters in normal people does not produce depression Antidepressant medications alter the levels of these neurotransmitters right away, but it takes a few weeks for the drugs to start relieving depression Receptor affinity changes and downregulation PSY2301: Biological Foundations of Behavior

Mood Disorders: Depression
Importance of reaction to stress HPA (Hypothalamic-pituitary-adrenal) Axis controls the production and release of hormones related to stress In depression, there is often an oversecretion of cortisol from the adrenal gland High levels of cortisol lead to the death of neurons in the hippocampus Estrogen and progesterone Menstrual cycles, postpartum period and menopause High levels of cortisol are bad for neurons, and chronically high levels lead to the death of neurons in the hippocampus PSY2301: Biological Foundations of Behavior

Mood Disorders: Depression
Neuroimaging Studies Depression is accompanied by increased blood flow and glucose metabolism in the: Orbital frontal cortex Anterior cingulate cortex Amygdala These elevations drop as the symptoms of depression remit following administration of antidepressant medication PSY2301: Biological Foundations of Behavior

Anxiety Disorders Six Different Types Generalized Anxiety Disorder Panic Disorder (Panic Attacks) Social Phobia Specific Phobias Post-Traumatic Stress Disorder Obsessive-Compulsive Disorder Even though there are different anxiety disorder, symptoms of anxiety are the saem PSY2301: Biological Foundations of Behavior

Anxiety Symptoms Somatic Goosebumps, Muscle tension, Heart rate increase, respiration accelerates, spleen contracts, peripheral blood vessels dilate, liver releases carbohydrates, bronchioles widen, perspiration increases Sympathetic autonomic system, adrenal-cortical system Behavioral Escape, avoidance, aggression, freezing, decreased appetitive responding, increased aversive responding Emotional Sense of dread, terror, restlessness, irritability Cognitive Anticipation of harm, exaggerating of danger, concentration problems, hypervigilance, worried thinking, fear of losing control, fear of dying, sense of unreality PSY2301: Biological Foundations of Behavior

Anxiety Disorders Panic Disorder Norepinephrine and serotonin Locus Coeruleus dysregulation causes panic attacks Limbic System: chronic anxiety Phobias Fear of something Agoraphobia: fear of public places Phobias about objects Social Phobia: fear of being judged or embarrased in front of other people Locus coeruleus regulates levels of norepinepherine PSY2301: Biological Foundations of Behavior

Anxiety Disorders : Generalized Anxiety Disorder
Excessive anxiety and worry, difficulty in controlling the worry, restlessness, easily fatigues, difficulty concentrating, irritability, muscle tension, sleep disturbance GABA Benzodiazepines effective for treatment Limbic system PSY2301: Biological Foundations of Behavior

Anxiety Disorders: PTSD
Symptoms: Reexperiencing the event Emotional numbing and detachment Hypervigilance and chronic arousal Trauma: Biological factors Physiological hyperactivity Increased blood flow in amygdala and anterior cingulate gyrus Hippocampus damage (but lower cortisol levels) Treatments: benzodiazepines and antidepressants Trauma: War Natural Disasters Abuse PSY2301: Biological Foundations of Behavior

Anxiety Disorders: Obsessive-Compulsive Disorder (OCD)
Obsessions: thoughts, images, ideas or impulses that are persistent and that intrude on a person’s consciousness Compulsions: behaviors or mental acts that an individual needs to perform Orbitofrontal cortex- caudate nucleus-thalamus Inability of patients to turn on these primitive impulses Serotonin-enhancing drugs improve symptoms PSY2301: Biological Foundations of Behavior

Anxiety Disorders Pharmacological Treatments SSRI benzodiazepines Cognitive-Behavior Therapy Pharmacological Treatments Benzodiazepines were once the primary treatment for anxiety disorders, but selective serotonin re-uptake inhibitors (antidepressants) are now commonly used treatments for anxiety Cognitive-Behavior Therapy Treatment for obsessive-compulsive disorder that challenges the reality of patients’ obsessions and the behavioral necessity for their compulsions PSY2301: Biological Foundations of Behavior

Psychiatric Disorders

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