DSM-IV

Because of limitations in the classical subtyping of Schizophrenia, a three-factor dimensional model (psychotic, disorganized, and negative) has been suggested to describe current and lifetime symptomatology. The psychotic factor includes delusions and hallucinations. The disorganized factor includes disorganized speech, disorganized behavior, and inappropriate affect. The negative factor includes the various negative symptoms. Studies suggest that the severity of symptoms within each of these three factors tends to vary together, both cross-sectionally and over time, whereas this is less true for symptoms across factors. For example, as delusions because more severe, hallucinations tend to become more severe as well. In contrast, the severity of negative or disorganized symptoms is less related to the severity of hallucinations or delusions. One model for understanding the clinical heterogeneity of Schizophrenia suggests that each of these three dimensions may have different underlying pathophysiological processes and treatment responses. Various combinations of severity on the three dimensions are encountered in clinical practice, and it is relatively uncommon for one dimension to be present in the complete absence of both of the others. The following is a system for applying these dimensions in research and clinical studies.

Specify: absent, mild, moderate, severe for each dimension. The prominence of these dimensions may be specified for either (or both) the current episode (i.e., previous 6 months) or the lifetime course of the disorder.

  • psychotic (hallucinations/delusions) dimension: describes the degree to which hallucinations and delusions have been present
  • disorganized dimension: describes the degree to which disorganized speech, disorganized behavior, or inappropriate affect have been present
  • negative (deficit) dimension: describes the degree to which negative symptoms (i.e., affective flattening, alogia, avolition) have been present. Note: Do not include symptoms that appear to be secondary to depression, medication side effects, or hallucinations or delusions.

Two examples that include the DSM-IV subtype, course specifiers, and the proposed dimensional approach are

Example 1: Schizophrenia, Paranoid Type, Continuous

  • Current:
    • With severe psychotic dimension
    • With absent disorganized dimension
    • With moderate negative dimension
  • Lifetime:
    • With mild psychotic dimension
    • With absent disorganized dimension
    • With mild negative dimension

Example 2: Schizophrenia, Residual Type, Episodic With Residual Symptoms

  • Current:
    • With mild psychotic dimension
    • With mild disorganized dimension
    • With mild negative dimension
  • Lifetime:
    • With moderate psychotic dimension
    • With mild disorganized dimension
    • With mild negative dimension

DSM-5

See Schizophrenia

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