Depression symptoms common in schizophrenia patients
MedWire News: Clinically relevant symptoms of depression are common in schizophrenia patients who have not been diagnosed with the mood disorder, results from a Spanish study suggest.
"In a review of more than 36 studies, the depression rate in patients with schizophrenia varied between 6% and 65%, with a modal rate of approximately 25%," explain Jaime Galan (Universidad Autónoma de Barcelona) and team.
They add: "These differences in the rates of depression among the different studies may be attributed to the definitions used for schizophrenia and/or depression."
For the current study, the researchers used the Calgary Depression Scale for Schizophrenia (CDSS) to assess the prevalence of depression among 90 stable outpatients with schizophrenia, schizoaffective disorder, or schizophreniform disorder who were aged 18-50 years. None of the patients had previously been diagnosed with the mood disorder.
The participants were also evaluated using the Positive and Negative Syndrome Scale (PANSS), the Scale for the Assessment of Negative Symptoms (SANS), the Scale to Assess Unawareness of Mental Disorder (SUMD), and the Barnes Akathisia Rating Scale (BARS).
In total, 28 (31%) patients tested positive for depression, as defined by a score of 5 or higher on the CDSS.
Patients with depression had significantly higher total PANSS scores than nondepressed patients, at 59.5 versus 47.6, as well as higher PANSS subscores for general psychopathology (30.3 vs 23.2), and negative symptoms (18.5 vs 14.5). Depressed patients also had significantly higher SANS and BARS scores than nondepressed patients, at 41.7 versus 29.2, and 2.0 versus 0.4, respectively.
The team found that CDSS scores highly correlated with the depressive subscale of the PANSS, and moderately correlated with the general psychopathology PANSS subscale. There was also moderate correlation between CDSS scores and SANS scores, but low correlation with PANSS negative symptom scores.
There was no correlation between depressive symptoms and positive symptoms, insight, or extrapyramidal symptoms, other than akathisia. However, the correlation between CDSS and BARS scores was low, the researchers note.
Galan and team conclude: "Our results suggest that patients with schizophrenia in a stable phase frequently have clinically relevant symptoms of depression, although they have not been diagnosed with depression, and that these symptoms, with the possible exception of a contribution from negative symptoms, are not secondary to other symptoms of their disorder or to extrapyramidal adverse effects of medications."
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By Mark Cowen