RESUMO
Sleep patterns, frequently altered in depression, have been hypothesized to be under genetic control. The circadian locomotor output cycles kaput (CLOCK) T3111C variant has been studied in association with sleep disturbances in depressed patients. The aim of this study was to investigate possible effects of T3111C CLOCK on insomnia, daytime sleepiness, sleep quality, and depression severity in a sample of 100 major depressive disorder patients. Inclusion criteria were: major depressive disorder, drug-free for any antidepressant and/or benzodiazepines for at least four weeks previously to the study, and a minimum score of >17 on the Hamilton Rating Scale for Depression. The Morningness-Eveningness Questionnaire, Epworth Sleepiness Scale, Athens Insomnia Scale, and Pittsburgh Sleep Quality Index were applied. No significant difference was found concerning genotype or allele groups and Hamilton Rating Scale for Depression items or clusters. No difference was found between genotypes and comorbidity, chronotype distribution, Epworth Sleepiness Scale, Athens Insomnia Scale, or Pittsburgh Sleep Quality Index total scores. Overall, the present findings did not support the hypothesis of an effect of the T3111C CLOCK variant on sleep disturbances in major depressive disorder. Further analysis of clock machinery will clarify the contribution of clock genes to the maintenance of mental health.
Assuntos
Relógios Biológicos/genética , Proteínas CLOCK/genética , Ritmo Circadiano/genética , Transtorno Depressivo Maior , Polimorfismo Genético , Transtornos do Sono-Vigília , Adolescente , Adulto , Transtorno Depressivo Maior/genética , Transtorno Depressivo Maior/fisiopatologia , Feminino , Humanos , Masculino , México , Pessoa de Meia-Idade , Transtornos do Sono-Vigília/genética , Transtornos do Sono-Vigília/fisiopatologia , Inquéritos e Questionários , Adulto JovemRESUMO
BACKGROUND: Rhythm disturbances are a frequent clinical manifestation of depression. In recent years a possible relationship between depression and chronotypes has emerged. Specifically eveningness has been proposed as vulnerability factor. The aim of this study was to describe sleep features of depressed patients according to chronotypes and to explore possible associations with the clinical features of depressive episodes. METHODS: 100 patients diagnosed with Major Depressive Disorder according to the Mini International Neuropsychiatric Interview (MINI) were included (age: 34+/-11.74, range: 18-60 years; female/male:79/21). At admission the Hamilton Rating Scale for Depression (HRSD) was administered. Patients were also administered the Morningness-Eveningness Questionnaire (MEQ), the Epworth Sleepiness Scale, the Athens Insomnia Scale and the Pittsburgh Sleep Quality Index. RESULTS: According to MEQ scores patients were classified in three groups: a) eveningness (n=18), b) neither (n=61) and c) morningness type (n=21). The age was different among chronotypes, being morningness-type patients older. The eveningness-type group showed higher scores in suicidal thoughts, more impaired work and activities, higher paranoid symptoms, higher scores on the anxiety cluster (HRSD), while the morningness-type group showed lower proportion of melancholic symptoms (MINI). We did not find association between sleep parameters and specific chronotypes. LIMITATIONS: The relatively small sample size and the concurrent assessment of chronotypes and depression may have biased our findings. CONCLUSIONS: Our data suggest the idea that chronotypes have an impact on depressive episodes features, with higher severity for the eveningness-type.