Objective: A depressive state and feelings of unhappiness in daily life are regarded as indispensable factors for the diagnosis of major depression. These factors are also speculated to contribute to subsequent psychological wellbeing.
Methods and participants: A total of 3190 men, aged 33 to 59 years, from a workplace in Japan participated in this one-year prospective study conducted from 2007 to 2008; 3141 men completed both evaluations (98.5%). The prevalences of depressive states and feelings of unhappiness were evaluated using a questionnaire. After one year, psychological wellbeing was evaluated using the General Health Questionnaire (GHQ) 12-item version. Analysis of variance and a logistic regression analysis were used for the analysis.
Results: The prevalence of no depressive feelings and no feelings of unhappiness among the workers were 73.5% among men in their 30s, 76.9% among men in their 40s, and 83.2% among men in their 50s. The mean GHQ score among participants with or without of depressive feelings and feelings of unhappiness was significantly higher than that among participants who had no depressive feelings and no feelings of unhappiness (control group). In contrast, the mean GHQ score among the participants in their 50s who had only depressive feelings did not differ from that in the control group of participants in their 50s according to a multivariate analysis.
Conclusions: Compared with depressive feelings, feelings of unhappiness were a stronger contributing factor to psychological wellbeing as measured using the GHQ questionnaire, especially among subjects in their 50s, in a one-year follow-up study.