What did we learn from research on comorbidity in psychiatry? Advantages and limitations in the forthcoming DSM-V era

Despite the large amount of research conducted in this area over the last two decades, comorbidity of psychiatric disorders remains a topic of major practical and theoretical significance. Official diagnostic and therapeutic guidelines of psychiatric disorders still do not provide clinicians and researchers with any treatment-specific indications for those cases presenting with psychiatric comorbidity. We will discuss the diagnostic improvement brought about, in clinical practice, by the punctual and refined recognition of threshold and subthreshold comorbidity. From such a perspective, diagnostic procedures and forthcoming systems of classification of mental disorders should attempt to combine descriptive, categorical and dimensional approaches, addressing more attention to the cross-sectional and longitudinal analysis of nuclear, subclinical, and atypical symptoms that may represent a pattern of either full-blown or partially expressed psychiatric comorbidity. This should certainly be regarded as a positive development. Parallel, continuous critical challenge seems to be vital in this area, in order to prevent dangerous trivializations and misunderstandings. © Dell'Osso and Pini; Licensee Bentham Open.