Patients with treatment-resistant schizophrenia (TRS) may have more minor physical anomalies (MPAs) and certain craniofacial features comparing to patients with non-TRS, according to a new study by researchers at National Taiwan University (NTU). This study has been published online on December 18, 2014 in Psychological Medicine.
Known as a serious mental illness, schizophrenia is estimated to have a lifetime morbid risk of 0.7 percent worldwide. Some individuals with schizophrenia show a poor response to pharmacological treatment, for example, no clinical improvement to at least two trials of antipsychotics, each lasting for six weeks. The prevalence of this kind of TRS has been estimated to be approximately 20–30 percent.
Conducted by Dr. An-Sheng Lin, a former master student at NTU and an attending psychiatrist at Bali Psychiatric Center in the northern Taiwan, and her advisor, Professor Wei J. Chen in the College of Public Health, the study investigated whether more MPAs or specific craniofacial features in patient with schizophrenia were associated with operationally defined treatment resistance. A comprehensive scale, consisting of both qualitatively measured MPAs and quantitative measurements of the head and face, was applied in 108 TRS patients and 104 non-TRS patients.
After controlling for multiple comparisons, the researchers found that patients with TRS had higher MPA scores in the mouth region among the six regional dimensions (global head, eyes, ears, mouth, hands, and feet) than non-TRS patients. Among the 27 items of craniofacial features, the TRS patients had narrowed facial width (bizygomatic distance), longer length of both lower facial height (from subnasale to gnathion) and facial height (from nasion to gnathion), and longer length of the philtrum than the non-TRS group. Among these dysmorphological measurements, three MPA items (mouth MPA score, facial width, and lower facial height) and earlier disease onset were further demonstrated to have good discriminant validity in distinguishing TRS from non-TRS patients in a multivariable logistic regression analysis, with an area under curve of 0.84 and a generalized R2 of 0.32.
“Our findings suggest that TRS is characterized by a higher MPAs score over the mouth region, a decreased facial width, an increased lower facial height, and early onset,” the authors write. “Our results add support to the neurodevelopmental underpinnings of the occurrence of treatment resistance. Future research can investigate the validation and the potential clinical use of our TRS-predicting model.”