Differences in Performance in the Trail Making Test Part B Between Adoptees With High and Low Genetic Risk for Schizophrenia Spectrum Disorders: The Finnish Adoptive Family Study of Schizophrenia.

The current study uses data from the Finnish Adoptive Family Study of Schizophrenia to investigate the association of genetic risk status and diagnosed psychiatric disorders with executive functioning, measured by Trail Making Test Part B (TMT-B), in adoptees with high and low genetic risk for schizophrenia spectrum disorders. The results showed no statistically significant differences in TMT-B completion times between adoptees with high and low genetic risk for schizophrenia spectrum disorders, although adoptees with high genetic risk for schizophrenia spectrum disorders as a group exhibited slightly slower performance. This contradicts previous studies reporting poorer TMT-B performance in unaffected first-degree relatives of individuals with schizophrenia. However, it aligns with studies that did not find differences in TMT-B performance between first-degree relatives of individuals with schizophrenia and controls. Significant differences in TMT-B completion times were observed among adoptees with psychiatric disorders, indicating that psychiatric morbidity associates with TMT-B performance, regardless of genetic risk. These findings indicate that various forms of psychopathology may hinder TMT-B performance, potentially due to reduced processing speeds or increased propensity towards a higher error rate. This highlights the link between psychopathology and cognitive impairment, underscoring this relationship as a critical focus for neuroscience research. Although TMT-B performance did not differ between adoptees with high and low genetic risk for schizophrenia spectrum disorders, our results do not rule out the existence of other cognitive deficits in adoptees with high genetic risk for schizophrenia spectrum disorders.