Associations among Impulsivity, Aggression, and Subthreshold Depression in Chinese University Students

Article excerpt

Depression is a severe mental disorder, the onset of which has been related to environmental, genetic, and personality factors. In the general population depressive disorder has a lifetime prevalence rate of 16.2% and a 12-month prevalence rate of 6.6%, making it one of the most common mental disorders (Kessler et al., 2003). As a group, new university students are undergoing a critical transitioning period. As a result, depression has been highlighted in university students and, in extreme cases, may lead to suicide.

Subthreshold depression is a prognostic variable for major depression that is very prevalent in China (Cuijpers, De Graaf, & van Dorsselaer, 2004) and decreases quality of life. People with subthreshold depression have an increased risk of developing major depression (Cuijpers et al., 2004).

In the current study we examined the relationship between impulsivity and subthreshold depression. There is less information pertaining to cases of depression, and subthreshold depression may manifest a weak relationship to impulsivity. It is relevant that in an epidemiological study it was found that impulsive suicide attempts were associated with high scores on the Beck Hopelessness Scale (Beck, Weissman, Lester, & Trexler, 1974), but with low depression scores (Simon et al., 2001). Impulsivity is complex and it is unclear whether or not increased impulsivity correlates with depression. Therefore, in this study we set out to explore more thoroughly the association between impulsivity and subthreshold depression.

Matsuura, Hashimoto, and Toichi (2009) found that about half of the inmates of a correctional facility were depressed, and the main effects of self-esteem and aggression were found to influence depression. However, in a previous study, Bjork, Dougherty, and Moeller (1997) analyzed behavioral data from their ongoing studies into aggression and found that more aggressive women tended to score higher on the Beck Depression Inventory (BDI), than did more aggressive men. Therefore, in the current study we sought to confirm whether or not there is any association between aggression and subthreshold depression, and if there is any gender-based difference therein.

Method

Study Population

The study was conducted with students at universities in Harbin, the capital of Heilongjiang Province and the tenth largest city in China. Harbin serves as a key political and economic center in northeastern China.

There are two main types of universities in China: national key universities, and general institutions. A national key university receives a high level of support from the central government of the People's Republic of China whereas general institutions are administered by the provinces. As the type on university an individual attends can decide their social position and worth, students in a national key university face more stress from academic performance requirements than do students at general institutions. There are 14 universities in Harbin; three of them are key national universities and 11 are general institutions.

Sample Size and Sampling Technique

Stratified random cluster sampling was employed in this study. To acquire a representative sample of university students in China, two key national universities and four general institutions in Harbin were randomly chosen. The distribution of samples from each university was then calculated according to the proportion of students who attend the two main types of universities. A stratified two-staged cluster selection of university students in full-time courses during the 2007-2008 academic year was used, with the sample being stratified into five grades (i.e., first, second, third, and fourth years, and postgraduate year); classes were randomly selected from these grades.

In this way, 6,000 students were selected from a total of 274,041 students in Harbin. In total, 2,844 students (1,493 female, 1,351 male) with BDI scores of 5 or higher were categorized as belonging to the depressive group; these individuals were invited to be tested on the Barratt Impulsiveness Scale (BIS), and the Buss-Perry Aggression Questionnaire (Buss & Perry, 1992). …