ABSTRACT
Identifying data-driven subtypes of major depressive disorder (MDD) is an important topic of psychiatric research. Currently, MDD subtypes are based on clinically defined depression symptom patterns. Although a few data-driven attempts have been made to identify more homogenous subgroups within MDD, other studies have not focused on using human genetic data for MDD subtyping. Here we used a computational strategy to identify MDD subtypes based on single-nucleotide polymorphism genotyping data from MDD cases and controls using Hamming distance and cluster analysis. We examined a cohort of Mexican-American participants from Los Angeles, including MDD patients (n=203) and healthy controls (n=196). The results in cluster trees indicate that a significant latent subtype exists in the Mexican-American MDD group. The individuals in this hidden subtype have increased common genetic substrates related to major depression and they also have more anxiety and less middle insomnia, depersonalization and derealisation, and paranoid symptoms. Advances in this line of research to validate this strategy in other patient groups of different ethnicities will have the potential to eventually be translated to clinical practice, with the tantalising possibility that in the future it may be possible to refine MDD diagnosis based on genetic data.
Subject(s)
Depressive Disorder, Major/diagnosis , Depressive Disorder, Major/genetics , Exome/genetics , Mexican Americans/genetics , Adult , Aged , Anxiety Disorders/diagnosis , Anxiety Disorders/ethnology , Anxiety Disorders/genetics , Cluster Analysis , Depersonalization/diagnosis , Depersonalization/ethnology , Depersonalization/genetics , Depressive Disorder, Major/classification , Female , Genotype , Humans , Los Angeles/ethnology , Male , Middle Aged , Paranoid Behavior/diagnosis , Paranoid Behavior/ethnology , Paranoid Behavior/genetics , Polymorphism, Single Nucleotide/genetics , Sleep Initiation and Maintenance Disorders/diagnosis , Sleep Initiation and Maintenance Disorders/ethnology , Sleep Initiation and Maintenance Disorders/genetics , Young AdultABSTRACT
BACKGROUND: Depersonalization occurs in healthy individuals and across a broad range of psychiatric patients. Data on depersonalization in persons linked to patients through genetics, environment or education are scarce. Due to their higher risk of developing psychosis, first-degree healthy relatives might show differences with the general population. This study examines depersonalization in patients with schizophrenia or schizophrenia spectrum disorders, their first-degree healthy relatives and normal controls. METHODS: The Cambridge Depersonalization Scale was used to measure depersonalization in a sample of 147 clinically stable patients with schizophrenia or schizophrenia spectrum disorders, 73 first-degree relatives with no psychiatric history and 172 healthy controls. Mixed effect models were used to account for both the familial structure of the data and the effect of sociodemographic characteristics. RESULTS: Patients obtained higher scores than relatives and controls for frequency and duration of depersonalization experiences, number of items responded positively and total depersonalization, while first-degree relatives obtained lower scores than patients and controls for all these characteristics. CONCLUSIONS: First-degree relatives of patients reported fewer episodes of depersonalization, which were less intense and of shorter duration, than healthy controls. This finding might be related to a protection mechanism that keeps first-degree relatives away from near-psychotic experiences. The nature of such a mechanism remains to be discovered.
Subject(s)
Depersonalization/complications , Psychotic Disorders/complications , Schizophrenia/complications , Adult , Depersonalization/genetics , Family , Female , Genetic Predisposition to Disease , Health Surveys , Humans , Male , Psychiatric Status Rating Scales , Psychotic Disorders/genetics , Schizophrenia/genetics , Schizophrenic Psychology , Surveys and QuestionnairesABSTRACT
85 students and 72 medical and surgical patients, aged between 16 and 24, and 48 mature-aged clerical and executive workers, aged between 29 and 60, were administered a written version of a scale measuring transient thought disorder, the Eysenck personality questionnaire and the EMBU questionnaire on parental rearing methods. It was found that there were differences between samples on frequency of depersonalisation, and that a majority of the young adult sample had had two or more depersonalisation experiences. Those who had experienced the greater degree of transient thought disorder had had fathers who were more intolerant, unaffectionate and unstimulating, and mothers who were more intolerant, unstimulating and rejecting. Transient thought disorder was related significantly to both psychoticism and particularly to neuroticism on the EPQ in the young, but not the mature adult, sample. It is suggested that it arises as a function of remote and uninvolved parents and is related to uncertainty about identity.
