The New DSM-5: Schizophrenia Spectrum and Other Psychotic Disorders
In this article, we discuss changes to the former DSM-IV category called Schizophrenia and Other Psychotic Disorders. The DSM-5 has added the word, “spectrum” to the title. The same basic diagnoses are still available in the DSM-5. Some symptom criteria were changed to make diagnosis more accurate and precise. Additionally, catatonia has been reconceptualized as a separate diagnostic feature that cuts across several broad categories of disorders. The distinction between bizarre and non-bizarre delusions is no longer diagnostically significant.
Schizophrenia subtypes have been eliminated:
Perhaps the most substantial change to this category of disorders is the elimination of subtypes (paranoid, disorganized, catatonic, undifferentiated, and residual). The rationale for doing away with these subtypes is they are not stable conditions, and have not afforded significant clinical utility nor scientific validity and reliability.
Catatonic specifiers and new Catatonic Disorders:
As mentioned above, the catatonic subtype has been eliminated. However, a catatonic specifier has been added and may be used with depressive, bipolar, and psychotic disorders. This change recognizes that catatonia occurs across several categories of disorders, without necessarily indicating psychosis. In addition, there are two new catatonic disorders: Catatonic Disorder due to Another Medical Condition and Other Specified Catatonic Disorder. Similar to the rationale for the catatonic specifier, the Catatonic Disorder due to Another Medical Condition recognizes that catatonia occurs in the context of several medical conditions. The Other Specified Catatonic Disorder may be used when the clinician is not yet certain of the underlying condition associated with catatonia. In other words, the clinician is uncertain whether the catatonia is related to depression, bipolar, psychotic, or medical conditions. DSM-5 requires 3 of 12 catatonic symptoms for all four conditions (depression, bipolar, psychotic, and medical). In DSM-IV, psychotic and mood disorders required 2 of 5 symptom sets, while medical conditions only required 1 of 5 symptom sets.
Symptom criteria changes:
Schizophrenia: Criterion A lists the five key symptoms of psychotic disorders: 1) delusions, 2) hallucinations, 3) disorganized speech, 4) disorganized or catatonic behavior, and 5) negative symptoms. In DSM-IV 2 of these 5 symptoms were required. However, only 1 of the 5 symptoms was required if delusions were bizarre or if hallucinations included a running commentary on a person's thoughts/behavior, and/or two or more voices conversing. This exception has been removed for lack of specificity and poor reliability. This change makes intuitive sense. The notion of what constitutes “bizarre” is rather vague, and its removal reduces cultural bias. In DSM-5, two of these five symptoms are required AND at least one symptom must be one of the first three (delusions, hallucinations, disorganized speech).
Schizoaffective: Schizoaffective disorder forms a link between psychosis and mood. Previously, DSM-IV required that the mood episode be present for a substantial duration of the illness. DSM-5 requires the mood episode be present for the majority of the illness. It probably seems like splitting hairs but the change was made to improve the reliability, validity, and stability of the disorder. After all, how long is “substantial” anyway?
Delusional Disorder: The requirement that delusions be non-bizarre has been removed. A ‘delusion bizarre type' specifier is available. Shared delusional disorder is no longer a distinct, separate disorder. It would simply be Delusional Disorder.
Differential diagnosis: Delusional Disorder and OCD delusional belief specifier:
A change that will be discussed in more detail in another article is the formation of a new category of disorders called Obsessive-Compulsive and Related Disorders. This new category of disorders includes Obsessive-Compulsive Disorder, Body Dysmorphic Disorder, and Hoarding Disorder (among others). These three disorders have a new specifier related to insight. The DSM-IV ‘with poor insight' specifier has been expanded to include good, fair, poor and absent/delusional insight. Therefore, Delusional Disorder has an exclusion criterion that specifies the symptoms cannot be better explained by OCD or similar disorder with absent/delusional insight. In other words, delusional beliefs no longer automatically suggest a psychotic disorder. They must be carefully evaluated to determine if another disorder can better account for the delusional beliefs.