[15.4] Schizophrenia

Question 1

Schizophrenia

Answer 1

• schizophrenia: a brain disease that causes the person to experience significant breaks from reality, a lack of integration of thoughts and emotions, and problems with attention and memory
• there are three distinct phases: prodromal, active, and residual; these tend to occur in sequence, although individuals may cycle through all three many times
• prodromal phase: people may become easily confused and have difficulty organizing their thoughts, they may lose interest and begin to withdraw from friends and family, and they may lose their normal motivations, withdraw from life, and spend increasing amounts of time alone, often deeply engrossed in their own thoughts
• active phase: people typically experience delusional thoughts, hallucinations, or disorganized patterns of thoughts, emotions, and behaviour
• residual phase: in which people’s predominant symptoms have disappeared or lessened considerably, and they may simply be withdrawn, have trouble concentrating, and generally lack motivation
• most significant and characteristic symptoms of schizophrenia:
• the tendency to experience hallucinations, delusions
• and disorganized patterns of thinking, feeling, and behaving
• hallucinations: alterations in perception, such that a person hears, sees, smells, feels, or tastes something that does not actually exist, except in that person’s own mind
• delusions: beliefs that are not based on reality (at least from the perspective of the person’s general culture)
• disorganized behaviour: describes the considerable difficulty people with schizophrenia may have completing the tasks of everyday life
• paranoid schizophrenia: symptoms include delusional beliefs that one is being followed, watched, or persecuted, and may also include delusions of grandeur or the belief that one has some secret or insight or power or some other characteristic that makes one particularly special
• disorganized schizophrenia: symptoms include thoughts, speech, behaviour, and emotion that are poorly integrated and incoherent; may also show inappropriate, unpredictable mannerisms
• catatonic schizophrenia: symptoms include episodes in which a person remains mute and immobile—sometimes in bizarre positions—for extended periods; may also exhibit repetitive, purposeless movements.
• undifferentiated schizophrenia: includes individuals who show a combination of symptoms from more than one type of schizophrenia
• residual schizophrenia: reflects individuals who show some symptoms of schizophrenia but are either in transition to a full-blown episode or in remission
• positive symptoms: the presence of maladaptive behaviours, such as confused and paranoid thinking, and inappropriate emotional reactions
• negative symptoms: involve the absence of adaptive behaviour, such as absent or flat emotional reactions, lack of interacting with others in a social setting, and lack of motivation

Question 2

Genetic Explanations for Schizophrenia

Answer 2

• as genetic relatedness increases, the chance that a relative of a person with schizophrenia will also develop the disorder increases
  
  • e.g. if one identical twin has schizophrenia, the other twin has a 25% to 50% chance of developing it; significantly higher than the 10% to 17% rate found in dizygotic (fraternal) twin pairs
• scientists have discovered a distinct pattern of genetic irregularities that is found in 15% of individuals with schizophrenia, compared with only 5% of healthy controls
  
  • but there still leaves the other 85% of individuals it wasn’t found in
• schizophrenia cannot be diagnosed by testing for a single gene, and the search for the complex genetic combinations that may underlie schizophrenia has barely begun

Question 3

Schizophrenia and the Nervous System

Answer 3

• people with schizophrenia have ventricular spaces that are 20% to 30% larger than people without schizophrenia
• the reason for these larger ventricular spaces is a loss of brain matter, which amounts to a reduction of total brain volume
• also have a lower level of activity in their frontal lobes
• have overactive dopamine receptors; excess dopamine can produce the types of positive symptoms associated with schizophrenia, such as hallucinations and delusions
  
  • but dopamine levels can’t account for the negative symptoms such as flattened emotion and lack of speech
• glutamate appears to be underactive in the hippocampus and frontal cortex
  
  • glutamate is a primary excitatory neurotransmitter, so a reduction of glutamate in those areas would correspond to a reduction of their functioning

Question 4

Environmental and Prenatal Factors

Answer 4

• people with schizophrenia are more likely to have been born during winter months
  
  • one hypothesis is that winter births carry a higher risk of eventual schizophrenia because the fetus’s brain is developing a great deal during the second trimester, which coincides with the onset of flu season
• more generally, environmental factors that cause stress for the mother while pregnant (e.g. losing her spouse or experiencing trauma) can impact fetal development
• head injuries occurring prior to age 10 put people who are genetically vulnerable to schizophrenia at greater risk for developing the disorder
• being raised in an environment where psychosocial stressors (e.g. interpersonal conflict, social isolation, poverty) are more abundant, puts individuals at greater risk, because schizophrenic episodes are often triggered by acutely stressful circumstances

Question 5

Social Factors

Answer 5

• the progression of the disease seems to be highly related to how emotionally supportive or critical members in the family are toward the person with schizophrenia
• families high in “emotional expressiveness” (EE) tend to be overly critical and controlling, whereas families low in EE tend to be more supportive, accepting, and non-judging
• Iin high-EE families, people with schizophrenia are three to four times more likely to experience a relapse of their symptoms within a nine-month period
• however, it’s not clear what the relationship between EE and schizophrenia may be
• people with more severe cases of schizophrenia are more difficult to manage, put more stress on the family, and therefore end up causing greater emotional expression in their families
• the full relationship between schizophrenia and emotional expressiveness may involve a two-way causal process

Question 6

Cultural Factors

Answer 6

• ethnicity influences the types of experiences that individuals report having
  
  • Anglo-Americans tend to focus on the mental experiences of the disorder, such as disorganized thinking and emotions
  • Mexican Americans focus more on how schizophrenia affects the body, such as by producing tension or tiredness
• beliefs about mental illness are linked to varying cultural views
  
  • many people throughout the world, such as the Swahili of Tanzania, believe that what we call schizophrenia is really a sign that spirits have invaded the body
  • in many cultures, the self is not perceived to be as separate and self-contained as in Western culture, but rather it is understood that the self is “permeable” to other entities or beings

Question 7

The Neurodevelopmental Hypothesis

Answer 7

• neurodevelopmental hypothesis: the adult manifestation of what we call “schizophrenia” is the outgrowth of disrupted neurological development early in the person’s life
• the sensitivity to environmental conditions exhibited by schizophrenia may indicate that the development of schizophrenia in adulthood can be traced back to the disruption of brain development early in life, even during prenatal development
• when psychologists viewed home movies of infants and children who subsequently developed schizophrenia, they noted that these children showed some unusual motor patterns, primarily on the left side of the body, such as jerky, repeated, and unnecessary arm movements
• in adolescence, psychologists can detect the schizophrenia prodrome, a collection of characteristics that resemble mild forms of schizophrenia symptoms
  
  • e.g. a teen might say, “I seem to keep hearing my mother calling my name before I fall asleep, even when I know she isn’t home.
• the precursors to schizophrenia are not unique to that disorder, but in fact are precursors to a variety of neurodevelopmental disorders