Genetic associations with psychosis and affective disturbance in Alzheimer's disease
Authors: Antonsdottir Inga Margret , Creese Byron , Klei Lambertus , DeMichele‐Sweet Mary Ann A. , Weamer Elise A. , Garcia‐Gonzalez Pablo , Marquie Marta , Boada Mercè , Alarcón‐Martín Emilio , Valero Sergi ,   NIA‐LOAD Family Based Study Consortium, Alzheimer's Disease Genetics Consortium (ADGC), AddNeuroMed Consortium, Liu Yushi , Hooli Basavaraj , Aarsland Dag , Selbaek Geir , Bergh Sverre , Rongve Arvid , Saltvedt Ingvild , Skjellegrind Håvard K. , Engdahl Bo , Andreassen Ole A. , Borroni Barbara , Mecocci Patrizia , Wedatilake Yehani , Mayeux Richard , Foroud Tatiana , Ruiz Agustín , Lopez Oscar L. , Kamboh M. Ilyas , Ballard Clive , Devlin Bernie , Lyketsos Constantine , Sweet Robert A. 
Published: May 2024

INTRODUCTION

Individuals with Alzheimer's disease (AD) commonly experience neuropsychiatric symptoms of psychosis (AD+P) and/or affective disturbance (depression, anxiety, and/or irritability, AD+A). This study's goal was to identify the genetic architecture of AD+P and AD+A, as well as their genetically correlated phenotypes.

METHODS

Genome‐wide association meta‐analysis of 9988 AD participants from six source studies with participants characterized for AD+P AD+A, and a joint phenotype (AD+A+P).

RESULTS

AD+P and AD+A were genetically correlated. However, AD+P and AD+A diverged in their genetic correlations with psychiatric phenotypes in individuals without AD. AD+P was negatively genetically correlated with bipolar disorder and positively with depressive symptoms. AD+A was positively correlated with anxiety disorder and more strongly correlated than AD+P with depressive symptoms. AD+P and AD+A+P had significant estimated heritability, whereas AD+A did not. Examination of the loci most strongly associated with the three phenotypes revealed overlapping and unique associations.

DISCUSSION

AD+P, AD+A, and AD+A+P have both shared and divergent genetic associations pointing to the importance of incorporating genetic insights into future treatment development.

Highlights

It has long been known that psychotic and affective symptoms are often comorbid in individuals diagnosed with Alzheimer's disease. Here we examined for the first time the genetic architecture underlying this clinical observation, determining that psychotic and affective phenotypes in Alzheimer's disease are genetically correlated.

Nevertheless, psychotic and affective phenotypes in Alzheimer's disease diverged in their genetic correlations with psychiatric phenotypes assessed in individuals without Alzheimer's disease. Psychosis in Alzheimer's disease was negatively genetically correlated with bipolar disorder and positively with depressive symptoms, whereas the affective phenotypes in Alzheimer's disease were positively correlated with anxiety disorder and more strongly correlated than psychosis with depressive symptoms.

Psychosis in Alzheimer's disease, and the joint psychotic and affective phenotype, had significant estimated heritability, whereas the affective in AD did not.

Examination of the loci most strongly associated with the psychotic, affective, or joint phenotypes revealed overlapping and unique associations.