Schizophrenia Notes

Schizophrenia

During severe periods, individuals with schizophrenia live in a private inner world, preoccupied with strange ideas and images. The term "schizophrenia" means "split mind," referring to a mind split from reality, characterized by disturbed perceptions, beliefs, disorganized speech, and diminished or inappropriate emotions and actions. Schizophrenia is a primary example of a psychotic disorder, profoundly disrupting relationships and work.

• With support and medication, over 40% of individuals with schizophrenia experience periods of normal life for a year or more.
• Only about one in seven experience a full and enduring recovery.

Symptoms of Schizophrenia

Schizophrenia presents in varied forms with symptoms categorized as:

• Positive Symptoms: Inappropriate behaviors are present.
• Negative Symptoms: Appropriate behaviors are absent.

Positive Symptoms:

• Disturbed perceptions, disorganized and deluded thinking, and inappropriate emotional expressions (laughter, tears, or rage).

Negative Symptoms:

• Absence of emotion in voice, expressionless faces, or mute and rigid bodies.

Disturbances in Perception and Beliefs:

• Hallucinations: False perceptions where individuals see, hear, feel, taste, or smell things that exist only in their minds (most often auditory hallucinations).
• Hallucinations can involve voices making insulting remarks or giving orders.
• Delusions: Disorganized, fragmented thinking distorted by false beliefs.
  • Paranoid Delusions: Belief that one is being threatened or pursued.
• Breakdown in selective attention may cause disorganized thinking.

Selective Attention Deficit:

• Difficulty filtering out unrelated stimuli, leading to easy distraction.
• This is one of many cognitive differences associated with schizophrenia.

Disorganized Speech:

• Thoughts spill out in no logical order.
• Jumbled ideas may make no sense even within sentences, forming "word salad."

Diminished and Inappropriate Emotions:

• Emotional expressions are often inappropriate and split off from reality.
• Examples include laughing after recalling a death or crying when others laugh.
• Flat Affect: Emotionless state of no apparent feeling.
• Impaired theory of mind, making it difficult to read other people's expressions and states of mind.
• Struggle to feel sympathy and compassion.
• Emotional deficiencies can occur early in the illness and have a genetic basis.
• Motor behavior may also be inappropriate and disruptive, including: Catatonia which is characterized by motor behaviors ranging from a physical stupor, remaining motionless for hours, to senseless, compulsive actions, such as continually rocking or rubbing an arm, to severe and dangerous agitation.

Onset and Development of Schizophrenia

• Estimated twenty million people worldwide (about one in 270) have schizophrenia.
• Typically strikes as young people mature into adulthood.
• Men tend to be diagnosed more often and earlier, with more severity.

Chronic Schizophrenia:

• Slow developing process with doubtful recovery.
• Social withdrawal (a negative symptom) is common.
• Men more often exhibit negative symptoms and chronic schizophrenia.

Acute Schizophrenia:

• Develops rapidly following life stresses.
• Recovery is more likely, with positive symptoms that respond to drug therapy.

Understanding Schizophrenia

• Heavily researched, linked with abnormal brain tissue and genetic predispositions.
• Considered a disease of the brain manifested in symptoms of the mind.

Brain Abnormalities

Biochemical Imbalances:

• Searching for blood proteins that might predict schizophrenia onset.
• Tracking mechanisms by which chemicals produce hallucinations and other symptoms.

Dopamine Overactivity:

• Excess number of dopamine receptors found post-mortem, including a six-fold excess for the dopamine receptor D4.
• Hyper-responsive dopamine system may intensify brain signals, creating positive symptoms like hallucinations and paranoia.
• Drugs that block dopamine receptors often lessen these symptoms.
• Drugs that increase dopamine levels (nicotine, amphetamines, cocaine) sometimes intensify symptoms.

Abnormal Brain Activity and Anatomy:

• Abnormally low brain activity in the frontal lobes (reasoning, planning, problem-solving).
• Decline in brain waves reflecting synchronized neural firing in the frontal lobes.
• Increased activity in the amygdala (fear processing center) in people with paranoia.
• Enlarged ventricles (fluid-filled brain cavities) and corresponding shrinkage/thinning of cerebral tissue.
• Often inherit brain differences, with a high likelihood of abnormalities in both affected identical twins.
• Greater brain shrinkage correlates with more severe thought disorder.
• Smaller than normal areas may include the cortex, hippocampus, and corpus callosum.
• Often, the thalamus is also smaller than normal, which may explain why filtering sensory input and focusing attention can be difficult for people with schizophrenia.
• Schizophrenia also tends to involve a loss of neural connections across the brain network.
• Involves problems with several brain regions and their interconnections.

Prenatal Environment and Risk

• Associated with prenatal development or delivery issues.
• Risk factors include low birth weight, maternal diabetes, older paternal age, and oxygen deprivation during delivery.
• Famine may also increase risks.
• Extreme maternal stress may be a contributing factor.
• Maternal infections (e.g., viral infections) during mid-pregnancy may impair fetal brain development.
• Increased risk if the country experienced a flu epidemic during fetal development.
• Increased risk in densely populated areas where viral diseases spread more readily.
• Increased risk for those born during winter and spring months (in utero during flu season).
• Mothers reporting influenza during pregnancy are more likely to bear children who develop schizophrenia (risk increased from 1% to 2% when infections occurred during the second trimester).
• Blood drawn from pregnant women whose offspring develop schizophrenia shows higher than normal levels of antibodies that suggest a viral infection.
• These converging lines of evidence suggest that fetal virus infections contribute to the development of schizophrenia.

Genetic Influences

• Genetic vulnerability to schizophrenia.
• The roughly one in 270 lifetime odds of any one person being diagnosed with schizophrenia become about one in ten among those who have a sibling or parent with the disorder.
• If the affected sibling is an identical twin, the odds increase to nearly one in two.
• These odds are unchanged even when the twins are reared apart.
  • Shares placentas which matters.
  • If the co-twin of an identical twin with schizophrenia shared the placenta, the chances of developing the disorder are six in ten.
  • If the identical twins had separate placentas, the co-twins' chances of developing schizophrenia drop to one in ten. Twins who share a placenta are more likely to share the same prenatal viruses, so perhaps shared germs as well as shared genes produce identical twin similarities.

Brain Abnormalities in Twins:

• In identical twins where only one has schizophrenia, typically only the affected twin's brain has enlarged fluid-filled cranial cavities.
• This difference implies a non-genetic factor (e.g., virus) is also at work.

Adoption Studies:

• Adopted children have a higher risk if a biological parent has schizophrenia.

Genes Matter:

• Analysis found 176 genome locations linked with this disorder, some affecting dopamine and other neurotransmitters.
• Another study of more than 100,000 people identified 413 schizophrenia-associated genes.
• Influenced by many genes, each with small effects.

Nature and Nurture Interact:

• Epigenetic factors influence whether genes will be expressed.
• Environmental factors (viral infections, nutritional deprivation, and maternal stress) can turn on genes that increase risk.
• Identical twins differing histories may explain why they show differing gene expressions.
• Our heredity and our life experiences work together.