Adult psychiatric outpatients; neuropsychiatric, neuropsychological and neurodevelopmental aspects

Abstract

ABSTRACT Background: Neurodevelopmental disorders - including autism and attention- deficit/hyperactivity (ADHD) - are relatively common in the general population with a total prevalence rate of at least 10%. Most research focuses on children or adolescents with neurodevelopmental disorder (NDD), and research on NDDs in adulthood often include study groups with no indicated comorbidity or with well-known comorbid conditions. It is unclear how common these disorders are among adult psychiatric patients, whether or not they have been missed in childhood, or if biomarkers and/or neuropsychological test batteries are helpful in diagnosis. Aims: The objectives were to estimate the prevalence rates of NDDs in an adult psychiatric outpatient clinic (AOP) clientele and to try to find new ways to delineate NDDs that would contribute towards more effective/appropriate assessments in clinical practice. Methods: Study I examined the neurodevelopmental diagnostics in newly referred psychiatric outpatients (N = 172) at an AOP in Liljeholmen, Stockholm, Sweden during 2016 through 2019. All new patients aged 18-25 years were offered an in-depth neuropsychiatric and general psychiatric assessment regardless of referral cause. The study also included iv neuropsychological assessment, testing of eye movements/gaze direction, galvanic skin response (GSR) testing, and examination of pupillary responses, the results of which were included in studies II-IV. In study II (n = 111) eye movements were analyzed. Neuropsychological aspects were analyzed in study III (n = 141). In study IV (n = 124) skin conductance and pupillary response were analyzed. Results: NDDs were diagnosed in 63 % of the patients attending the AOP regardless of reason for referral. NDDs had often been missed in childhood, especially among female patients. There was significant comorbidity across NDD diagnoses- especially between ADHD and autism - and between NDD and “traditional” psychiatric diagnoses, including anxiety disorder and depression. Using a data-driven eye-tracker analysis, we found that patients with high scores for autism traits and depressive symptoms respectively were less prone to look in the eyes of the individuals on the pictures presented. Also, the well-established left sided gaze direction bias seen in "control populations" was diminished. Patients with ADHD did not show these characteristics. There were no differences between patients with and without ADHD in any of the executive function tests that were administered as part of the neuropsychological assessment. There were no differences in the neuropsychological test results that were clinically relevant in the diagnostic process. Conclusions: The results suggest that NDDs need to be diagnostically considered in AOPs, and that NDDs unrecognized in childhood, perhaps particularly in females, might lead to secondary psychiatric problems. Indirectly the results suggest that a broad focus on girls regarding NDDs is needed in services for children and adolescents. The results of the studies further suggest that it may be helpful to use eye tracking and GSR in the assessment of ASD. The results of the studies did not support the notion that neuropsychological test batteries focusing on executive function in AOP patients might help discriminate those with NDDs from those without.