Week 3 Notes NUR 6970: Physiology of Psychosis PDF

# Study Outline: The Physiology of Posychosis ## **I.** Introduction - Focus: Biological basis of posychosis and the defining features of psychotic disorders, with an emphasis on schizophrenia. - Goal: To understand the physiological mechanisms underlying psychosis and differentiate among various p...

# Study Outline: The Physiology of Posychosis ## **I.** Introduction - Focus: Biological basis of posychosis and the defining features of psychotic disorders, with an emphasis on schizophrenia. - Goal: To understand the physiological mechanisms underlying psychosis and differentiate among various psychotic disorders. ## **II.** Dopamine and Psychosis - Dopamine Excess: A key factor in psychotic symptoms. - D2 Receptors: Excess dopamine binding at D2 receptors in the mesolimbic pathway is strongly associated with psychosis. - Psychosis as a symptom: This can be caused by various factors, not just schizophrenia. - Schizophrenia: The most common psychotic disorder, used as a foundation for discussion. It has diagnostic criteria. ## **III.** Dopamine Pathways in Schizophrenia - Four Pathways: - Mesolimbic: Implicit in psychoses for ANY reason - Mesocortical: More associated with schizo or affected by antipsychotics. - Nigrostriatal: More associated with schizo or affected by antipsychotics. - Tuberoinfundibular (Tuberohypophyseal): More associated with schizo or affected by antipsychotics. - The image shows four dopamine pathways in the brain. - Mesolimbic: Involved with positive symptoms of schizophrenia. - Mesocortical: Involved with negative and cognitive and affective symptoms of schizophrenia. - Nigrostriatal: Involved with extrapyramidal symptoms and tardive dyskinesia, which can be side effects of medication. - Tuberohypophyseal: Involved with hyperprolactinemia, which can be a side effect of medication. ## **IV.** Mesolimbic Pathway - The "psychotic pathway". - Connects the ventral tegmental area (VTA) to the nucleus accumbens (reward centre). - Implicit in motivation, pleasure, reward. - Excess dopamine leads to: - Increased pleasure, reward, and motivation. - Positive symptoms of schizophrenia (hallucinations, delusions). - Implicated in all forms of posychosis. ## **V.** Mesocortical Pathway - Connects the VTA to the prefrontal cortex (PFC). - Reduced dopamine leads to: - Negative symptoms of schizophrenia (flat affect, cognitive deficits, social withdrawal, executive function, appropriate expression of emotion/cognition, problem solving). - Negative symptoms are associated with poorer long-term outcomes: important diagnostic marker. - Antipsychotics can worsen negative symptoms by further reducing dopamine in this pathway. ## **VI.** Nigrostriatal Pathway - Connects the substantia nigra to the striatum (motor control). - Normally unaffected in schizophrenia. - Antipsychotics can disrupt this pathway, leading to: - Extrapyramidal symptoms (EPS): Involuntary movements (e.g., tremors, rigidity). - Deficiencies of dopamine implicit in movement disorders (Parkinson's) - "Thorazine shuffle": controls psychoses; causes abnormal movements. - Akathisia: Restlessness and inability to sit still. ## **VII.** Tuberoinfundibular Pathway - Connects the substantia nigra to the hypothalamus (prolactin production). - Normally unaffected in schizophrenia. - Antipsychotics can disrupt this pathway, leading to: - Hyperprolactinemia: Elevated prolactin levels. - Galactorrhea: Milk production outside of breastfeeding. - Menstrual irregularities, difficulty conceiving. ## **VIII.** Antipsychotic Medications - Aim to control dopamine activity in the mesolimbic pathway while minimizing effects on other pathways. - Newer antipsychotics are generally better at achieving this balance. ## **IX.** Differentiating Among Psychoses - Psychosis is a symptom, not a diagnosis. - Important to characterize the type of posychosis: - Diagnostic criteria for schizophrenia = at least one positive sx (hallucination, delusion, or dissociation) - Hallucinations: Sensory perceptions without external stimuli. - Auditory (most common in psychotic disorders) - Visual (can be associated with psychotic disorders or organic conditions) - Tactile, olfactory, gustatory (more likely to have organic causes) - Delusions: Fixed, false beliefs despite evidence to the contrary or rational argument. - Various types and themes (grandiosity, persecution, infidelity, religion, nihilistic - life has no meaning, somatic, guilt) - Common types: mood or atmosphere, perception, memory, ideas, awareness. - Characterize the psychosis: - Auditory hallucinations are most commonly associated with psychotic disorders. - Visual hallucinations: - Psychotic disorders - Tumors along the optic pathway - Gustatory hallucinations: - More likely to be an organic problem: order imaging. - Allergies, head injury. - Olfactory hallucinations (phantosmia): - Infection, dental disease, stroke, nasal polyps, migraines - Tactile hallucinations: - Stimulants, ETOH excess, neuro disease ## **X.** Psychotic Disorders - Deduce if it is a symptom: - **Schizophrenia:** Chronic psychotic disorder with positive symptoms (hallucinations, delusions), negative symptoms, and functional impairment. Requires symptoms for at least 6 months. - **Schizoaffective Disorder:** Meets criteria for both schizophrenia and a mood disorder (MDD, BPD I, BPD II). - **Schizophreniform Disorder:** Symptoms of schizophrenia but for less than 6 months. - **Brief Psychotic Disorder:** Psychotic symptoms lasting less than one month. - **Delusional Disorder:** Persistent delusions without other psychotic symptoms. - **Substance-Induced Psychosis:** Psychosis caused by substance use. - **Psychotic Disorder Due to a Medical Condition:** Psychosis caused by an underlying medical condition (i.e., head injury, metabolic imbalance, organic lesion). - **Paraphrenia:** Chronic psychotic disorder similar to schizophrenia but with better-preserved affect and functioning. ## **XI.** Key Takeaways: - Excess dopamine in the mesolimbic pathway is a key factor in psychosis. - Different dopamine pathways are involved in various aspects of schizophrenia and its treatment. - Antipsychotics aim to control posychosis while minimizing side effects. - It’s important to differentiate between various types of psychotic disorders to ensure appropriate treatment. ## **I.** Introduction to Dissociation - Definition of dissociation: Disconnection between a person’s thoughts, memories, feelings, or self of self. - Everyone dissociates sometimes. It is not in itself a disorder unless it disrupts social or occupational function. - Normal vs. abnormal dissociation: - Everyday examples (daydreaming, highway hypnosis). - Therapeutic uses (hypnosis). - Dissociation as a coping mechanism: - Examples of situations where dissociation might occur (trauma, accidents, crime victim). ## **II.** Characteristics of Dissociative Disorder - Abrupt onset and offset. - Positive and negative disruptions: - Positive: Experiences that shouldn’t be there (e.g., feeling detached from your body). - Negative: Lack of experiences that should be there (e.g., memory loss). - Triggered by psychological conflict or trauma. - Impaired functioning or distress. ## **III.** Types of Dissociative Disorders - Depersonalization/Derealization Disorder: - Depersonalization: Detachment from oneself (physical, cognitive, or emotional self). - Derealization: Feeling that surroundings are unreal, common = people around them are not real people. - Often triggered by stress. - Reality testing remains intact. - Begins in early childhood - almost always before age 16. - Dissociative Amnesia: 2 requirements for dx: - Forgotten something important (usually distressing or traumatic information). - Other causes ruled out. - Inability to recall important personal information, usually related to trauma. - Begins suddenly and often precipitated by severe stress. - Physical injury - Severe guilt or internal conflict - May list minutes or years: usually ends abruptly with complete return of memory - Types - Localized: No recall for events within a particular time frame. - Selective: Certain portions of time are lost. - Generalized: All experiences of the lifetime are forgotten. - Continuous: Loss of all memory from a certain time to the present. - Systematized: Loss of certain classes if information (i.e., everything about work) - The longer the event of continuous and generalized amnesia, the poorer the prognosis. - Dissociative Fugue: - Sudden, unexpected travel away from home with amnesia for identity. - May assume a new identity. - Severe stressor -> sx commonly lasts a few hours or days. - Recovery is sudden. - Dissociative Identity Disorder (DID): - Formerly known as multiple personality disorder. - Presence of two or more distinct personalities with unique attributes: - Mood - Perception - Recall - Control of thought and behavior - Often associated with severe childhood trauma: **Seeing a Therapist is Important**. - Each identity has unique characteristics (names, age, gender). - Significant gaps in memory and personal information. - Identity switching triggered by stress. ## **IV.** Somatic Symptom and Related Disorders: - Somatic Symptom Disorder: - Distressing physical symptoms with no identifiable medical cause. - Common symptoms: pain, shortness of breath, palpitations, abdominal problems. - They genuinely feel the sx, but it is a psychiatric condition. - Often leads to extensive medical evaluations. - Sx DO NOT respond to tx that are usually effective. - No control of sx UNTIL pt has to acknowledge that it is a mental health etiology and wants to seek tx for it. - ABD and head pain are common. - Conversion Disorder: - Altered voluntary motor or sensory function with no neurological explanation. - Examples: Blindness, paralysis, seizures, deafness, diplopia, hallucinations, paralysis, dysphagia. - Performing a GOOD PHYSICAL EXAM can differentiate a cause. - Symptoms do not conform to anatomical patterns - Sx produces distress or disability. - Illness Anxiety Disorder: - "Hypochondriac". - Healthy people with a serious fear of a life-threatening illness. - Needs repeated reassurance. - Common in young adulthood (30 to 40 y/o). - >6 months duration. - Preoccupation with having or acquiring a serious illness. - High anxiety about health, even with minimal or no symptoms. - Psychological Factors Affecting Other Medical Conditions: - Mental health conditions (e.g., depression, anxiety) impacting physical health. - Examples: Depression worsening chronic pain, hallucinations interfering with treatment adherence (rejects tx). ## **V.** Factitious Disorder: - Factitious Disorder Imposed on Self (Munchausen’s Syndrome): - Deceptive falsification of physical or psychological symptoms for the purpose of assuming the sick role. - Dramatic s/s that are atypical. - They tend to complain and argue when hospitalized. - Often have coincident personality disorders. - May undergo unnecessary medical procedures. - More common in males. - Factitious Disorder Imposed on Another (Munchausen’s Syndrome by Proxy): - Falsification of symptoms in another person, typically a child, for the purpose of gaining attention or sympathy. - "Model mother" - Mother may be excited about bad news. - Not too concerned when given bad news. - Sx do not make sense. - Typical tx do not work. - Death rate = 10%. - They will go to different hospitals and facilities. - Permanent disfigurement or disability = 70%. ## **VI.** Malingering: - **Not a somatic disorder because they do not have the sx**. - Intentional fabrication or exaggeration of symptoms for external gain (e.g., financial compensation, avoiding work, drugs). - VERY difficult to detect.