Dementia and Severe Schizophrenia Share Similar Cognitive Patterns

People with behavioral variant frontotemporal dementia and schizophrenia have similar neurobiological patterns.

People with behavioral variant frontotemporal dementia (bvFTD) and schizophrenia have similar neurobiological patterns, according to a recent study published in JAMA Psychiatry.

Frontotemporolimbic alterations and cognitive deficits present early in schizophrenia, the researchers said. Temporal, prefrontal, and insular abnormalities are also linked to worse outcomes in people with psychotic disorders and depression. Shared neurobiology and genetic traits among people with certain psychiatric disorders and dementias have been of interest to researchers as of late.

… [W]e observed a gradient of increasing neuroanatomical heterogeneity ranging from bvFTD to schizophrenia and MD due to a stronger differentiation of disease signatures in patients with schizophrenia and MD.

To explore these complex associations, the authors used a machine learning tool to look for patterns in brain MRI images of patients with bvFTD, mild cognitive dementia, early-stage Alzheimer’s disease (AD), established AD, and major depression (MD). They also explored 2-year functioning in people with high-risk psychosis or depression, among other outcomes. The study included 1870 patients.

Researchers found severe cognitive impairment in patients with bvFTD and established AD which differed from the other groups. People with bvFTD experienced psychiatric symptoms such as “affective flattening” and irritability. Patients with bvFTD received antipsychotic drugs and antidepressants more often than people with AD.

“More generally, we observed a gradient of increasing neuroanatomical heterogeneity ranging from bvFTD to schizophrenia and MD due to a stronger differentiation of disease signatures in patients with schizophrenia and MD,” researchers stated. “Thus, these signatures could provide meaningful intermediate phenotypes of neurofunctional systems differentially affected by bvFTD and AD and facilitate the decomposition of neurobiological heterogeneity in psychiatric disorders.”

Researchers admitted the follow-up period (2 years) was short compared with other studies, which may have reduced their ability to make associations. The training sample size was also smaller than they would have liked, which could have affected analysis. “Further studies into molecular disease pathways are needed to clarify how different pathophysiological processes project on overlapping neural alterations in bvFTD and schizophrenia-spectrum disorders,” they concluded.

Disclosure: Some study authors declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of authors’ disclosures. 

References:

Koutsouleris N, Pantelis C, Velakoulis D, et al. Exploring links between psychosis and frontotemporal dementia using multimodal machine learning: dementia praecox revisitedJAMA Psychiatry. Published online August 3, 2022. doi:10.1001/jamapsychiatry.2022.2075