Abnormal Psychology

Schizophrenia and Other Psychotic Disorders 529

or substance-related disorder, and the psychotic symptoms only arise during a mood

episode or with substance use or withdrawal. For instance, people with mania may

become psychotic, developing grandiose delusions about their abilities. Psychotic

mania is distinguished from schizophrenia by the presence of other symptoms of

mania—such as pressured speech or little need for sleep. Psychotically depressed

people may have delusions or hallucinations; the delusions usually involve themes

of the depressed person’s worthlessness or the “badness” of certain body parts (e.g.,

“My intestines are rotting”).

Substance-related disorders can lead to delusions (see Chapter 9), such as the

paranoid delusions that arise from chronic use of stimulants. Substances (and with-

drawal from them) can also induce hallucinations, such as the tactile hallucinations

that can arise with cocaine use (e.g., the feeling that bugs are crawling over a per-

son’s arms).

Some negative symptoms of schizophrenia can be diffi cult to distinguish from

symptoms of other disorders, notably depression: People with schizophrenia or de-

pression may show little interest in activities, hardly speak at all, give minimal replies

to questions, and avoid social situations (American Psychiatric Association, 2000).

As noted in Table 12.2, although both of these disorders may involve similar out-

ward behaviors, the behaviors arise from different causes. With schizophrenia, these

behavioral symptoms stem from the cognitive defi cits associated with the disorder. In

general, people with schizophrenia but not depression do not have other symptoms of

depression, such as changes in weight or sleep or feelings of worthlessness and guilt

(American Psychiatric Association, 2000). Of course, people with schizophrenia may

develop comorbid disorders, such as depression or substance abuse. The presence of

any comorbid disorder can make it more diffi cult to determine the correct diagnoses.

Behavioral Symptoms Causes in Depression Causes in Schizophrenia

Little or no interest in

activities, staring into

space for long periods

of time

Lack of pleasure in activities

(anhedonia), diffi culty

making decisions

Diffi culty initiating behavior

(avolition)

Short or “empty” replies

to questions

Lack of energy Diffi culty organizing thoughts to

speak

Social isolation Lack of energy, anhedonia,

feeling undeserving of

companionship

Feeling overwhelmed by social

situations, lack of social skills

Table 12.2 • Behavioral Symptoms Common to Depression and Schizophrenia

Psychotic Disorders

Although mood disorders and substance-related disorders may involve psychotic

symptoms, the diagnostic criteria for these two categories of disorders do not spe-

cifi cally require the presence of psychotic symptoms. In contrast, the criteria for

the disorders collectively referred to as psychotic disorders specifi cally require the

presence of psychotic symptoms. Psychotic disorders are considered to lie on a

spectrum, related to each other in their symptoms and risk factors but differing

in their specifi c constellations of symptoms, duration, and severity. In addition to

schizophrenia, these disorders include schizophreniform disorder, brief psychotic

disorder, schizoaffective disorder, delusional disorder, and shared psychotic disor-

der. Although it is not classifi ed as a psychotic disorder, the personality disorder

schizotypal personality disorder (discussed in Chapter 13) is thought to be part of

the spectrum of schizophrenia-related disorders (Kendler, Neale, & Walsh, 1995).

Let’s examine each of these disorders in turn.