External Validation by Machine Learning and Reduction of the Input Dimensions of the D-PSY Scale for Dimensional Psychopathology

There have been debates about whether psychiatric disorders should be classified according to categories (categorical model) or according to a continuum between normal and pathological functioning (dimensional model). While the former is the main one used to facilitate reliability, it has several limitations. We will use machine learning to develop a predictive model, bridging the gap between the dimensional and categorical approaches. Psychometric measures obtained from a questionnaire will be collected. Then, a supervised descriptor selection approach will be applied to predict categorical outcomes from dimensional inputs. The resulting prediction will be based on nonlinear modeling based on universal approximators. We developed this input questionnaire with four main objectives: 1) to briefly scan most of the categories generally described in the international nosography; 2) to use a continuous scale following a dimensional approach; 3) to use positively oriented sentences to decrease social desirability bias; 4) to be less confronting for the patient.The questionnaire is built on dimensions, whereas psychiatric diagnoses are built on categories. We will model the transition from one to the other. This approach will allow us to verify the hypotheses of diagnostic categories construction in psychopathology, integrated in the RDoC approach; and later on to standardize the psychometric measures used in cognitive-behavioral therapy treatments.200 adults will undergo a standard clinical interview (SCID-5, First et al., 2017), and the psychological screening self-report questionnaire (D-Psy) and additional questionnaires measuring social desirability dissociation, phobia and autism.

Inclusion Criteria:Adults over 18 years old and less than 65 years old who are fluent in French (oral and written), with suspicions of psychopathology.Protected adults and pregnant women cannot participate.Exclusion Criteria:Participant with neurological or organic mental disorder (not induced by substances) including dementia, organic amnesic syndrome, delirium;other mental, personality or behavioural disorders due to brain damage, dysfunction or to physical disease.