Understanding Psychology (10th Ed)

FIGURE 9 
The closer the genetic links between two people, the greater the likelihood that if 
one experiences schizophrenia, so will the other sometime during his or her lifetime. However, 
genetics is not the full story; if it were, the risk of identical twins having schizophrenia would 
be 100% and not the 48% shown in this fi gure. 
(Source: Gottesman, 1991.)
Risk of Developing Schizophrenia, Based on 
Genetic Relatedness to a Person with Schizophrenia
 
Genetic 
Risk of Developing
Relationship 
Relatedness, % 
Schizophrenia, %
Identical twin 
100 
48
Child of two schizophrenic parents 
100 
46
Fraternal twin 
50 
17
Off spring of one schizophrenic parent
50 
17
Sibling 50 
9
Nephew or niece 
25 
4
Spouse 0 
2
Unrelated person 
0 
1
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528 Chapter 
15 
Psychological Disorders
 ENVIRONMENTAL PERSPECTIVES ON SCHIZOPHRENIA 
Although biological factors provide important pieces of the puzzle of schizophrenia, 
we still need to consider past and current experiences in the environments of people 
who develop the disturbance. For instance, psychoanalytic approaches suggest that 
schizophrenia is a form of regression to earlier experiences and stages of life. Freud 
believed that people with schizophrenia lack egos that are strong enough to cope 
with their unacceptable impulses. They regress to the oral stage—a time when the 
id and ego are not yet separated. Therefore, individuals with schizophrenia essen-
tially lack an ego and act out impulses without concern for reality. 
Although this reasoning is theoretically plausible, little evidence supports psy-
choanalytic explanations. Somewhat more convincing theories look toward the emo-
tional and communication patterns of the families of people with schizophrenia. For 
instance, some researchers suggest that schizophrenia results from high levels of 
expressed emotion. Expressed emotion is an interaction style characterized by family 
members’ criticism, hostility, and emotional intrusiveness. Other researchers suggest 
that faulty communication patterns lie at the heart of schizophrenia (Miklowitz & 
Thompson, 2003; Lobban, Barrowclough, & Jones, 2006). 
Psychologists who take a cognitive perspective on schizophrenia suggest that the 
problems in thinking that people with the disorder experience point to a cognitive 
cause. Some suggest that schizophrenia results from overattention to stimuli in the 
environment. Rather than being able to screen out unimportant or inconsequential 
stimuli and focus on the most important things in the environment, people with 
schizophrenia may be excessively receptive to virtually everything in their environ-
ment. As a consequence, their information-processing capabilities become overloaded 
and eventually break down. Other cognitive experts argue that schizophrenia results 
from underattention to certain stimuli. According to this explanation, people with 
schizophrenia fail to focus suffi ciently on important stimuli and pay attention to 
other, less important information in their surroundings (Cadenhead & Braff, 1995). 
Although it is plausible that overattention and underattention are related to dif-
ferent forms of schizophrenia, these phenomena do not explain the origins of such 
information-processing disorders. Consequently, cognitive approaches—like other 
environmental explanations—do not provide a full explanation of the disorder.