ABCD Study Already Producing Results

Though the ABCD study has not yet finished enrolling participants, this ambitious project is already paying dividends. A study published June 6 in JAMA Psychiatry, for example, found that data collected at ABCD enrollment using a brief self-report questionnaire can reliably measure psychotic-like symptoms in children aged 9 and 10.

The Prodromal Questionnaire–Brief version (PQ-B) is a validated, 21-item questionnaire that assesses the presence of psychotic-like experiences in adults and adolescents. These experiences, which include mild delusional thoughts or perceptual abnormalities, can occur in children as well. If the PQ-B could be adapted for children, the researchers theorized, it would enable earlier screening and prevention interventions for psychosis.

As part of the ABCD baseline measurements, most children took a modified PQ-B child version (PQ-BC). Of the 3,984 participants (average age 10) in the study, the children who scored higher on the PQ-BC had several other traits that have been linked to psychosis risk in adolescents and adults. Higher PQ-BC scores were associated with a family history of psychotic disorders (but not family history of depression or mania), higher rates of internalizing symptoms, and lower scores on neuropsychological tests.

The researchers, led by Nicole Karcher, Ph.D., of the University of Washington in St. Louis, noted that the PQ-BC had strong measurement invariance, which meant it performed well across different ethnicities and genders—an important finding if the PQ-BC is to be used in clinical settings.

“[F]ollow-up studies, including longitudinal follow-up of these [ABCD] children, should explore how the combination of factors examined in the present study may be useful in predicting outcomes in at-risk children,” the researchers wrote.

“Assessment of the Prodromal Questionnaire–Brief Child Version for Measurement of Self-Reported Psychoticlike Experiences in Childhood” can be accessed here.