Abstract
In recent decades, the rate of very preterm birth (<32 weeks of gestation) has increased, and it is now estimated as occurring in approximately 1 in 9 live births. Multiple lines of research suggest that very preterm birth is associated with a range of psychiatric and neurodevelopmental problems throughout childhood and adolescence. However, little is known about adult outcomes. This PhD sought to delineate the cognitive and psychiatric profile of adults born very preterm. It included four related studies. Firstly, IQ trajectories were examined in order to understand whether IQ improves or remains stable from the age of 8 to the age 30 years. The results indicated that individuals who were born very preterm and especially those born at the lower end of the gestational age spectrum, continue to be at higher risk of cognitive impairment in adult life, affecting Performance IQ in particular. Secondly, cognitive outcomes were compared between very preterm born adults and age-‐matched controls, with an emphasis on executive function. The influence of cognitive outcomes on social functioning and achievement was also examined. Individuals born very preterm performed worse than controls on measures of IQ and executive function. They also demonstrated significantly lower achievement levels in terms of years spent in education, employment status, and on a measure of functioning in work and social domains. Persisting executive function impairments in very preterm survivors were associated with achievement in several real-‐life domains. Thirdly, considering that very preterm birth is associated with an increased rate of psychiatric disorders, a dimensional approach was utilized to examine psychiatric symptomatology in adults who were born very preterm and controls. Moreover, the specificity of this risk was examined in order to better understand their adult clinical profile. Very preterm individuals demonstrated elevated psychiatric symptomatology compared to full-‐term controls. Psychiatric risk was characterized by a non-‐specific clinical profile and was associated with lower IQ. Lastly, salience attribution, thought to underlie psychiatric symptomology, was examined. Adults born very preterm displayed reduced capacity to process adaptive salience, indicating they may have difficulties in distinguishing between high and low probability stimuli features. Salience processing was associated with negative and positive psychotic-‐like symptoms, lending support to the hypothesis that very preterm individuals may be a distinct subgroup of high-‐risk individuals, characterized by increased ‘cognitive’ psychotic-‐like experiences. This study aimed to understand the neuropsychiatric and cognitive profile of adults born very preterm. It demonstrated that in adulthood they experience similar difficulties to those that are evident earlier in life. These findings emphasize the need for cognitive remediation programmes to be delivered to vulnerable groups, which thus far have targeted specific executive function components (e.g. working memory, cognitive control), and may one day show generalizable benefits for a successful overall life adjustment.| Date of Award | 2018 |
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| Original language | English |
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| Supervisor | Serena Counsell (Supervisor) & Chiara Nosarti (Supervisor) |