Chapter 16 Summary & Outline

The Toll of Psychiatric Disorders Is Huge

• Epidemiology reveals that psychiatric disorders are startlingly prevalent in modern society. Review Table 16.1

Study questions: 1 | 2

Schizophrenia Is the Major Neurobiological Challenge in Psychiatry

• There is strong evidence for a genetic factor in the origin of schizophrenia. Consistent evidence comes from studies of the incidence of schizophrenia in families, twins, and adoptees. Several genes that may contribute to schizophrenia have been identified. Review Table 16.2 and Figure 16.2
• Structural changes in the brains of patients with schizophrenia—including enlarged ventricles, limbic system abnormalities, loss of gray matter in the cortex, and abnormalities of other brain regions—may arise from early developmental problems. Functional-imaging studies indicate that, in schizophrenia, the frontal lobes are less active than normal. Review Figures 16.4–16.9
• Biochemical theories of schizophrenia especially emphasize the importance of the transmitters dopamine, glutamate, and serotonin. Typical neuroleptics block D₂ receptors, while atypical neuroleptics block 5HT_2A receptors. Despite pharmaceutical marketing, the two appear to be equally effective. Review Figures 16.10 and 16.11
• According to an integrative psychobiological model, the emergence of schizophrenia depends on the interaction of a vulnerable biological substrate and environmental stressors. Review Figure 16.12

Study questions: 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27

Mood Disorders Are a Major Psychiatric Category

• Biological studies of depression reveal a strong genetic factor and the importance of levels of various neurotransmitters, including serotonin.
• People suffering from depression show increased blood flow in the frontal cortex and the amygdala, and decreased blood flow in the parietal and posterior temporal cortex. Review Figure 16.13
• The most effective approach to treating depression may be a combination of cognitive behavioral therapy (CBT) and treatment with a selective serotonin reuptake inhibitor (SSRI).
• Dysregulation of the hypothalamic-pituitary-adrenal axis is often associated with depression. Review Figure 16.14
• In the general population, females are more likely than males to suffer from depression.
• Changes in REM sleep that accompany depression include shortened onset to REM sleep and larger percentages of REM sleep in overall amounts of sleep. Review Figure 16.15
• Bipolar disorder is characterized by extreme mood swings and subtle changes in the brain, and it has a complex genetic component. The disorder is commonly treated with lithium. Review Figure 16.16

Study questions: 28 | 29 | 30 | 31 | 32 | 33 | 34 | 35 | 36 | 37 | 38 | 39 | 40 | 41 | 42 | 43 | 44 | 45 | 46 | 47 | 48

There Are Several Types of Anxiety Disorders

• Anxiety states are characterized by functional changes in the temporal lobes that can be revealed by PET scans and functional MRI.
• Benzodiazepine antianxiety drugs (anxiolytics) affect receptors for the transmitter GABA, enhancing its inhibitory influence. Drugs that affect serotonergic transmission may also reduce anxiety. Review Figure 16.17
• Posttraumatic stress disorder (PTSD) is characterized by an inability to forget horrible experiences. Temporal lobe atrophy in this disorder is common and may be caused by exposure to glucocorticoids, but long-term PTSD sufferers have paradoxically low levels of glucocorticoids. Review Figure 16.18
• Obsessive-compulsive disorder (OCD) is characterized by changes in basal ganglia and frontal structures and strongly linked to serotonin activities. It bears many similarities to Tourette’s syndrome, in which people display motor and verbal tics and compulsions. Review Table 16.4 and Box 16.3

Study questions: 49 | 50 | 51 | 52 | 53 | 54 | 55 | 56 | 57 | 58 | 59 | 60 | 61 | 62 | 63 | 64

Neurosurgery Has Been Used to Treat Psychiatric Disorders

• Though once a common approach to psychiatric treatment, today neurosurgery is used to treat only the most severe and unresponsive cases.

Study questions: 65 | 66 | 67

Abnormal Prion Proteins Destroy the Brain

• Infectious proteins (prions) become concentrated in brain tissues, leading to damage and dementia in bovine spongiform encephalopathy (BSE) and, in humans, Creutzfeldt-Jakob disease. Review Figure 16.20

Study questions: 68

Review Web Activity 16.1 for a concept review.