482 TA B L E Chapter 12 Psychological Disorders 12.4 Type Frequency Prominent Features Paranoid schizophrenia 40 percent of people with schizophrenia; appears late in life (after age 25–30) Delusions of grandeur or persecution; anger; anxiety; argumentativeness; extreme jealousy; onset often sudden; signs of impairment may be subtle. Disorganized schizophrenia 5 percent of all people with schizophrenia; high prevalance in homeless population Delusions; hallucinations; incoherent speech; facial grimaces; inappropriate laughter/giggling; neglected personal hygiene; loss of bladder/bowel control. Catatonic schizophrenia 8 percent of all people with schizophrenia Disordered movement, alternating between total immobility (stupor) and wild excitement. In stupor, the person does not speak or attend to communication. Undifferentiated schizophrenia 40 percent of all people with schizophrenia Patterns of disordered behavior, thought, and emotion that do not fall easily into any other subtype. Residual schizophrenia Varies Applies to people who have had prior episodes of schizophrenia but are not currently displaying symptoms. Subtypes of Schizophrenia These traditional categories of schizophrenia convey some useful information, but subtype labels are not always accurate. Some symptoms of schizophrenia appear in more than one subtype, and people ﬁrst placed in one subtype might later display characteristics of another. These concerns, plus the fact that DSM-IV subtypes may not be linked to different causal factors, have led researchers to develop additional ways of categorizing schizophrenia, such as whether positive or negative symptoms are most prominent in a given case (Villalta-Gil et al., 2006). Categorizing Schizophrenia DSM-IV lists ﬁve major subtypes of schizophrenia: paranoid, disorganized, catatonic, undifferentiated, and residual. These subtypes are summarized in Table 12.4. Researchers have also made other useful distinctions among various forms of schizophrenia. One of these distinctions involves the positive-negative symptom dimension. Disorganized thoughts, delusions, and hallucinations are sometimes called positive symptoms of schizophrenia, because they appear as undesirable additions to a person’s mental life (Andreasen et al., 1995; Racenstein et al., 2002). In contrast, the absence of pleasure and motivation, lack of emotion, social withdrawal, reduced speech, and other deﬁcits seen in schizophrenia are sometimes called negative symptoms, because they appear to subtract elements from normal mental life (Nicholson & Neufeld, 1993). Many patients exhibit both positive and negative symptoms, but when the negative symptoms are stronger, schizophrenia generally has a more severe course, including long-term disability and relative lack of response to treatment (e.g., Milev et al., 2005; Racenstein et al., 2002). Yet another way of categorizing schizophrenic symptoms focuses on whether they are psychotic (e.g., hallucinations, delusions), disorganized (e.g., incoherent speech, chaotic behavior, inappropriate affect), or negative (e.g., lack of speech or motivation). Some researchers believe that each symptom cluster or dimension may ultimately be traceable to different causes. For this reason, schizophrenia is often referred to as the schizophrenia spectrum (Tsuang, Stone, & Faraone, 2000).