Transdiagnostic approach needed to combat limits of disorder-specific mental health research, treatment

Avshalom Caspi

Life histories of most mental disorders involved various successive disorders, according to results of a cohort study published in JAMA Network Open.

“Progress in conceptualizing mental disorders has been delayed by the field’s limiting focus on cross-sectional information,” Avshalom Caspi, PhD, the Edward M. Arnett professor of psychology and neuroscience at Duke University, and professor of personality development at the Institute of Psychiatry, Psychology & Neuroscience at King’s College London, told Healio Psychiatry. “Mental health professionals typically encounter a patient at one point in his or her life. This cross-sectional view fosters a focus on the current presenting disorder and on the assumption that diagnosis informs etiology and prognosis; however, we know very little about how mental disorders unfold over the life span.”

Caspi and colleagues noted that new evidence from neuroimaging, genetic and risk-prediction studies suggests that major etiological findings are transdiagnostic.

The researchers sought to describe mental disorder life histories across the first half of the life course. They included mental health data of 1,013 participants who were born in New Zealand from 1972 to 1973 and were enrolled in the population-representative Dunedin Study — the first cohort to measure disorders in children using standardized diagnostic interviews. Researchers observed participants from birth to age 45 years, with an end date of April 2019. Diagnosed impairing disorders assessed nine times from ages 11 to 45 years, as well as brain function assessed through neurocognitive examinations conducted at age 3 years, neuropsychological testing during childhood and adulthood, and midlife neuroimaging-based brain age, served as main outcomes and measures.

Results showed the proportions of participants who met the criteria for a mental disorder were as follows:

• 35% at ages 11 to 15 years;

• 50% at age 18 years;

• 51% at age 21 years;

• 48% at age 26 years;

• 46% at age 32 years;

• 45% at age 38 years; and

• 44% at age 45 years.

Disorder onset occurred by adolescence among 59% (n = 600) of participants and eventually affected 86% (n = 869) of the cohort by midlife. By age 45 years, 85% (n = 737) of those with a disorder had accumulated comorbid diagnoses, according to the researchers. Further, those with adolescent-onset disorders subsequently met the criteria for more diverse disorders and presented with disorders at more past-year assessments. The researchers observed a general factor of psychopathology, revealed through confirmatory factor analysis summarizing mental life histories across 4 decades. Longitudinal analyses revealed that high p-factor scores, which indicated extensive mental disorder life histories, were linked to the following:

• poor neurocognitive functioning at age 3 years;

• childhood-to-adulthood cognitive decline; and

• older brain age at midlife.

“Studying disorders one at a time does not accurately represent most patients’ lived experience of shifting across disorder families,” Caspi told Healio Psychiatry. “Studying one disorder may mislead about specificity and hide transdiagnostic discoveries from view. There is a need for measurement instruments that capture shared liability of shifting disorders across the life course in order to make discoveries more efficiently. There is also a need to develop transdiagnostic treatments that can prevent many different conditions.” – by Joe Gramigna

Disclosures: The authors report no relevant financial disclosures.