A study recently published in Psychiatry Research has shown schizophrenia to have high diagnostic stability over time. However, the majority of the research has focused primarily on early psychotic episodes.
This systematic review included 39 studies performed between 1980 and 2017, which were largely sourced from the US National Library of Medicine National Institutes of Health database PubMed.gov. Eligibility criteria included the availability of information regarding diagnostic stability of schizophrenia, participant age of at least 15 years, specific International Classification of Diseases Ninth Edition and Diagnostic and Statistical Manual of Mental Disorders (III, IV, and V) diagnoses of schizophrenia and psychoses, a sample size larger than 10, and publications in peer-reviewed journals. Of the studies included, 23 focused on psychotic episodes, 11 on general psychiatric disorders, and 5 on schizophrenia, with 69.23% (n=27) of studies having a prospective design. The total number of participants was 39,965.
The mean consistency was 84.29%±11.21% among prospective studies and 67.15%±13.05% among retrospective studies, with a mean proportion of diagnostic change of 31.28% (n=12). In studies regarding schizophrenia, diagnostic stability was more common among participants who were men, older, in later stages of illness, and who had poorer functioning, mental illness in their family history, and a longer hospital length of stay. In studies related to psychosis and psychotic episodes, there was greater stability among women, those who were older, and those with a longer untreated psychosis duration. Most diagnostic changes led to a diagnosis of schizophrenia.
Limitations to this study include a systematic review study design, cultural differences between study populations, a lack of diagnostic measurement of change to or from schizophrenia, and a small number of studies focused on schizophrenia.
The study researchers concluded that “[s]chizophrenia was found to be one of the most stable [diagnoses] and stability tended to increase over time. On the other hand, factors related to longer and better assessment of patients (such as in-patient setting, longer duration of stay, number of hospitalizations, later stages of illness) led to a more accurate and stable diagnosis from early stages of the illness. Consequently, making an early precise diagnosis remains a goal yet to be achieved in the clinical practice. Diagnostic stability of schizophrenia was found to be very high, particularly when compared with other psychiatric disorders. However, consensus criteria for diagnostic stability and validated tools for its measurement are needed, which may lead to further research on this topic.”
Palomar-Ciria N, Cegla-Schvartzman F, Lopez-Morinigo JD, Bello HJ, Ovejero S, Baca-García E. Diagnostic stability of schizophrenia: A systematic review [published online May 2, 2019]. Psychiatry Res. doi: 10.1016/j.psychres.2019.04.020