How to prescribe and interpret genetic testing in psychiatry?

The last decade has witnessed major advances in psychiatric genetics and have established that the genetic architecture of major psychiatric disorders (i.e. schizophrenia, bipolar disorders…) includes both rare variants conferring high risk and common variants with low impact (polymorphisms). Rare variants refer to Single Nucleotide Variants (SNV) and Copy Number Variants (CNV, chromosomal microdeletions and microduplications). Polymorphisms can be aggregated into polygenic risk scores.

While polygenic risk scores are considered research analyses and are not recommended for clinical use, some results on rare genetic variants can already be translated into psychiatric practice. For instance, patients with neurodevelopmental disorders (i.e. autism, intellectual disability…) could benefit from chromosomal microarray analysis for CNV detection, fragile X molecular testing and whole-exome (WES) or whole genome sequencing (WGS). Geneticists and psychiatrists can already order genetic testing for psychotic disorders.

Identification of genetic variants may help psychiatric patients to better understand and accept their diagnoses and could improve the psychiatric genetic counselling for familial recurrence risk. The genetic approach could also be efficient for alleviating emotional distress and guilt and in improving self-efficacy and empowerment of patients and their family. Additionally, the detection of some rare variants can improve the care by allowing the detection of other comorbidities and by giving clues to adapt the psychotropic treatments. Integrating the genetic psychiatry into clinical practice requires a substantial training effort and awareness about legal, ethical and practical challenges.

This course will present the current knowledge on the genetic architecture of major psychiatric disorders, will describe the state-of-the art of the genetic testing and counseling in Europe, will advertise some clinical vignettes showing the benefit and the pitfalls of genetics in psychiatry. The course will contain interactive presentations, role plays and a debate about the interest and the challenges of implementing genetic testing in clinical practice.

Course Director: Boris Chaumette, France