Abnormal Psychology

520 CHAPTER 12

Nora, Iris, Myra, and Hester Genain were identical quadruplets. All four suffered from schizophrenia,

although this outcome is statistically unlikely. The symptoms and course of the disorder were different

for each sister, illustrating the range of ways it can affect people.

Miss Edna Morlok Courtesy of Genain family

What Are Schizophrenia and Other

Psychotic Disorders?

Schizophreniais a psychological disorder characterized by psychotic symptoms—

hallucinations and delusions—that signifi cantly affect emotions, behavior, and

most notably, mental processes and mental contents. The symptoms of schizo-

phrenia can interfere with a person’s abilities to comprehend and respond to

the world in a normal way. DSM-IV-TR lists schizophrenia as a single disorder

(see Chapter 3, and Table 12.1), but research suggests that schizophrenia is not

a unitary disorder (Blanchard, Horan, & Collins, 2005; Turetsky et al., 2002).

Instead, like depression (see Chapter 6), schizophrenia is a set of related disor-

ders. Research fi ndings suggest that each variant of schizophrenia has different

symptoms, causes, course of development, and, possibly, response to treatments.

Let’s examine in more detail the symptoms and types of schizophrenia and other

related psychotic disorders.

The Symptoms of Schizophrenia

The criteria for schizophrenia in DSM-IV-TR fall into two clusters:

• positive symptoms, consisting of delusions and hallucinations and disorganized
  speech and behavior;


• negative symptoms, consisting of the absence or reduction of normal mental
  processes, mental contents, feelings, or behaviors, including speech, emotional
  expressiveness, and/or movement.

Let’s examine in detail the DSM-IV-TR criteria (Table 12.1), criticisms of these cri-

teria, and an alternative way to diagnose schizophrenia.

Positive Symptoms

Positive symptoms are so named because they are marked by the presence of

abnormal or distorted mental processes, mental contents, or behaviors. Positive

symptoms of schizophrenia are

• hallucinations (distortions of perception),


• delusions (distortions of thought),


• disorganized speech, and


• disorganized behavior.

Schizophrenia
A psychological disorder characterized by
psychotic symptoms that signifi cantly affect
emotions, behavior, and mental processes
and mental contents.

Positive symptoms
Symptoms of schizophrenia that are marked
by the presence of abnormal or distorted
mental processes, mental contents, or
behaviors.