Schizophrenia

1. Schizophrenia • A group of severe disorders characterized by disorganized and delusional thinking, disturbed perceptions, and inappropriate emotions and behaviours. • Those with paranoid tendencies are particularly prone to delusions of persecution. • Disorganized thinking may result from a breakdown in selective attention. (Reichenberg & Harvey, 2007) • Hallucinations are sensory experiences without sensory stimulation, most often auditory. • The expressed emotions of schizophrenia are often utterly inappropriate, split off from reality. (King & Caponigro, 2010). • Other emotional breaks: flat affect; difficulty in perceiving facial emotions and reading other's states of mind. (Green & Horan, 2010).

2. Subtypes of Schizophrenia • Memorize Table 50.1 (m659 c633 15.4)for the next exam. • Schizophrenia typically strikes young people maturing into adulthood (late teens and early twenties). Men tend to be struck earlier, more severely, and slightly more often. (Picchioni & Murray, 2007). • Schizophrenia (Gk. for 'shattered mind *not* split personality'), is a cluster of disorders. • Positive symptoms are hallucinations, disorganized speech, delusional thoughts, inappropriate emotional responses to social stimuli. • Negative symptoms are toneless voices, expressionless faces, mute or rigid bodies, which equals flat affect. • When schizophrenia is chronic, process, slow onset, recovery is doubtful.

3. Subtypes of Schizophrenia Cont'd • Those with chronic schizophrenia often exhibit the incapacitating symptoms of withdrawal. (Kirkpatrick et al., 2006) • Men, whose onset is 4 years earlier, more often exhibit negative symptoms and chronic schizophrenia. (Rasanen et al., 2000) • Rapid or acute schizophrenia following life stresses predicts a more rapid and likely recovery. They often have more positive symptoms that respond to drug therapy. (Fowles, 1992). • Might imbalances in brain chemistry underlie schizophrenia, as was the case of the 'mad hatter', British hatmakers moistened the brims of mercury-laden hats with their tongue and lips (Smith, 1983).

4. Brain Abnormalities • Schizophrenia is likely caused by a sixfold excess of the D4 dopamine receptor. (Seeman et al., 1993) • Hyper-responsive dopamine system may intensify brain signals, creating positive symptoms. (Grace, 2010). • Drugs that block dopamine receptors often lessen these symptoms, drugs that increase dopamine levels, such as amphetamines and cocaine, sometimes intensify them. (Seeman 2007). • Some schizophrenics have abnormally low activity in the frontal lobes (Morey et al., 2005) • One study took PET (positron emission tomograph) scans of brain activity while people were hallucinating. (Silbersweig et al., 1995). When they heard a voice or sight, their brains became vigorously active in the thalamus.

5. Brain Abnormalities Cont'd • Schizophrenics also display a noticeable decline in synchronized neural firing in the frontal lobes. (Symond et al., 2005) • Out-of-sync neural firing may disrupt the integrated functioning of neural networks. Combine this with increased activity in the amygdala, and paranoia is the sure result. (Epstein et al., 1998) • Sulci are enlarged, and fluid-filled, with a corresponding shrinkage of cerebral tissue. (Goldman et al., 2009) • Smaller-than-normal thalamus may explain why schizophrenics have difficulty filtering sensory input and focusing attention. (Ellison-Wright et al., 2008) • Risk factors include low birth weight, maternal diabetes, old paternal age, and oxygen deprivation during delivery. (King et al., 2010). Think triggers, not causes.

6. Maternal Virus During Midpregnancy • Could an intrauterine viral infection be the cause? • Pregnant during a flu epidemic? (Wright et al., 1995) • If the mother had the flu during pregnancy, will their child be more at risk? Yes, but only during the second trimester. (Brown et al., 2000) • Does blood drawn from pregnant women with a schizophrenic child show higher-than-normal levels of antibodies (suggesting a viral infection)? Yes. (Brown et al. 2004) • Another study found traces of a specific retrovirus (HERV) in nearly half of people with schizophrenia and virtually none in healthy people. (Perron et al., 2008) • Does the infection weaken glial cells, leading to reduced synaptic connections (Moises et al., 2002)

7. Twins and Schizophrenia • Identical twins share a prenatal environment; about 2/3 share a placenta. If one has schizophrenia, the co-twin's chances are 6 in 10 if they shared a placenta. • If they had separate placentas, the chances are 1 in 10. (Phelps et al., 1997) • Children adopted by someone who develops schizophrenia seldom develop the disorder, instead they have an elevated risk if their biological parent has it. (Gottesman, 1991). • Epigenetic factors influence gene expression: viral infections, nutritional deprivation, maternal stress. Identical twins' differing histories in the womb and beyond explain why only on of them may show differing gene expression. (Walker et al., 2010).