Gender differences in depression: symptom patterns, risk factors, and etiology

Table of contents

Abstract

Introduction

Methods

Symptom patterns and measurement: children and adolescents

Symptom patterns and measurement: adults

Risk factors and course of disease: children and adolescents

Risk factors and course of disease: adults

Discussion and conclusions

Literature

Appendix

Abstract

Marked gender differences with respect to the prevalence and symptoms of depression have been observed for years. The aim of this selective review is to give a rather broad and comprehensive overview of the topic by looking at gender differences in depression from various angles, including symptom patterns and measurement, risk factors, course of disease, and etiology in both children and adults. Important findings of the last two years are described and discussed, including recommendations for further research and health care practice.

Introduction

Depression is one of the most frequent psychic disorders throughout the world, if not the most frequent one. Its typical natural course is characterised by recurrent episodes of disease highly endangering social functioning and well-being of the patients. Chronification is common. In line with these well-established facts, the World Health Organization expects depression to be the leading cause of loss of disability-free life years by the year 2020 (Murray & Lopez, 1996). Marked gender differences with respect to the prevalence of depression have been observed for decades, with women having a risk that is almost twice as high than the risk of men (for Germany see Jacobi, Klose & Wittchen, 2004). Up to present, however, it is still not clear what are the reasons for these obvious gender differences. Are they due to different symptom patterns among men and women, differences in self-disclosure and help-seeking behaviour? Or is a greater genetic vulnerability of women, to develop depressive moods, responsible? Are the sexes exposed differently to specific risk factors, or do mainly differences in basic socio-demographic variables explain the gender differences in depression? Another possible explanation consists in the use of generally gender-biased diagnostic instruments.

The aim of this paper is to describe the current state of knowledge about gender differences in depression by giving a selective overview of relevant international literature of the last 2 years.

Methods

A literature research was carried out in February 2009 by entering the search terms “gender differences” AND “depression”, “male depression”, or “female depression” separately into the Pubmed search engine. The search was restricted to current literature from the years 2007-2009 in either English, German or Spanish language. The named search terms had to appear either in the title or the abstract of the article. Articles dealing with very specific subgroups like female prisoners or subgroups suffering from specific comorbid psychic or somatic disorders were excluded from the search. Only articles that were available right away via the institutional access of Mainz University were considered for the review. In the end, 28 relevant articles were collected. Table 1 gives a short overview of key features of these articles. First author, publication year, study design, study sample, instrument(s) used for the measurement of depression, main topic, and country in which the study was carried out, are displayed. The two articles by Möller Leimkühler, Heller and Paulus (2007) refer to the same study and report the same results. All the other articles refer to different studies or study samples.

Table 1: Key features of the included articles (n = 28)

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***For an explanative list of abbreviations used in table 1 see appendix ***

As indicated in table 1, this literature review does not focus on any specific hypothesis or research question, but tries to give a rather broad and comprehensive overview of the topic instead. Thus, it looks at gender differences in depression from various angles, including symptom patterns and measurement, risk factors and course of disease in both children and adults.

Symptom patterns and measurement: children and adolescents

During childhood, both the average extent of depression and prevalence rates seem to be similar among boys and girls. In a sample of middle-class students aged 10-12 years, Bailey, Zausniewski, Heinzer & Hemstrom-Krainess (2007) found that there were no significant differences with respect to the sum scores of the instrument administered. T]epper, Liu, Guo, Zhai, Liu & Li (2008) found similar results for two community samples of Chinese children and adolescents. There were no significant differences regarding sum scores or prevalence rates of depression between the genders in self-ratings. Instead, depressive symptoms (both sum score and prevalence rate) increased with age. Fu-I & Wang (2008) analysed a clinic sample in Brazil and also found that adolescents had higher levels of depression than children with respect to certain symptoms, i.e. depressed mood, lower self-esteem, and difficulties concentrating. There are hints, however, that not only the overall extent of depression increases with age, but that there are differential effects according to gender. When students were assessed by their teachers in the study by Tepper et al. (2008), a significant gender x age interaction showed. Before age 12, Chinese boys were rated to have higher depression scores, but after age 12, Chinese girls were assessed as being more depressed. This finding is consistent with a review by Afifi (2007). He comes to the conclusion that adolescent girls have been found to experience low and moderate levels of depression more often than boys. In short, prevalence rates and extent of depression seem to be similar in childhood and begin to diverge, when adolescence is reached.

As to the symptom patterns, there seem to be some differences between the genders. In the Brazilian sample (Fu-I & Wang, 2008), female adolescents between 10 and 17 years had significantly lower self-esteem than all other groups, whereas adolescent boys between 10 and 17 years had significantly greater difficulties concentrating. There were no such gender differences with regard to the children (aged 5-9 years) in the sample. Bailey et al (2007) could demonstrate similar gender differences in symptom patterns for children aged 10-12 years. Girls had more negative self-esteem and more negative mood. They seemed to internalise more than boys, who in turn externalised more than girls and thus suffered more from school problems or interpersonal problems. Hence, there seem to be gender differences with respect to the symptoms of depression from quite an early age on.

Symptom patterns and measurement: adults

Afifi (2007) states that, among adults, gender differences with respect to prevalence rates do exist, but differ according to countries. He also emphasises that there are numerous similarities that hold for both genders. According to his review, there are for example no gender differences with regard to the age at first onset of disease, the use of and response to anti-depressive medication, and the severity of depressive episodes in hospital settings.

Smith, Kyle, Forty, Cooper, Walters, Russell, Caesar, Farmer, McGuffin, Jones, Jones & Craddock (2008), on the other hand, reported a significantly earlier onset of disease in women in a sample of subjects with recurrent major depressive disorder (MDD). In line with the longer duration of disease, women in this study had on average more depressive episodes, and apart from that, reported significantly more depressive symptoms during their worst episode of depression than men. Smith et al. (2008) also found a higher proportion of atypical depression among women. With respect to the symptom pattern, women suffered from diminished libido, excessive sleep, diurnal variation of mood and excessive self-reproach more frequently than men, whereas the latter reported initial insomnia more often. The presence of increased self-reproaches in women was interpreted by the authors as a cognitive style that could be responsible for the generally increased depression rates in women. Romans, Tyas, Cohen & Silverstone (2007) add to the evidence of gender-dependent symptom patterns with findings from their population-based study: Depressed women suffered more often from increased appetite, tearfulness, a loss of interest and thoughts of death than depressed men, even after adjustment for a whole bunch of socio-demographic variables. Moreover, women in this study reported a higher mean number of symptoms than men. MDD was more frequent among women with a female to male ratio of 1.64, which is consistent with previous findings (Jacobi et al., 2004). The differences in tearfulness and increase in appetite between depressed men and women lead the authors to raising the question, if these characteristics of depressed women are rather due to being female than to being depressed. Since these items were not asked in a healthy population, it is not known, if women in the general population also tend to report tearfulness and increase in appetite more often than men. If this was the case, then the named items should not be used in depression measurement. Leach, Christensen & Mackinnon (2008) followed a similar line of thought. In their community-based study, they tried to find out, if gender-biased items in diagnostic instruments are a possible explanation for the gender differences in depression. Using multiple groups analyses, they came to the conclusion that for different age groups (see table 1) the same model of depression held for both genders. So, at least for the Goldberg Scales of Anxiety and Depression (Goldberg, Bridges, Duncan- Jones & Grayson, 1988), which was used by the authors, gender differences in the endorsement of items do not seem to be due to gender-biased items, but to real differences.

Möller Leimkühler et al. (2008) also focussed on the topic of gender-specific measurement of depression. In their survey of male adolescents, they used an instrument specifically designed for the detection of male depression (Gotland Scale of Male Depression, cf. Rutz, 1999). This instrument both comprises standard depressive items as well as distress items which are supposed to measure specific symptoms displayed by depressed males, e.g. aggressive behaviour, abusive behaviour, or irritability. There was no evidence that the regular depressive symptoms are generally masked by distress symptoms in males, as had been suggested. Males at risk of depression, however, reported significantly more distress symptoms than depressive symptoms, whereas non-depressive males reported more depressive symptoms than distress symptoms. Moreover, the authors could identify two general symptom clusters in the sample, both in the risk-group and in the non-risk group. One was characterised by relatively higher values in the distress symptoms, the other one was characterised by relatively higher values in the depressive symptoms. The authors come to the conclusion that male distress symptoms should be considered as additional diagnostic criteria in depression assessment. In males at high risk of depression, they could have the function of maintaining a “healthy” male faqade. Since depressive symptoms seem to be a general phenomenon among male adolescents, depression is not likely to develop directly via an aggravation of depressive symptoms, but rather via an aggravation of male distress symptoms, which are not covered by regular diagnostic instruments.

Halbreich & Kahn (2007) focussed more on special characteristics of female depression. In their review, they support the hypothesis that gender differences concerning depression rates are mainly due to specific depressive phenotypes that are more common among women. They refer to anxious depression, atypical, and somatic depression, which are accompanied by more anxious and more somatic symptoms. This approach seems to match the findings published by Smith et al. (2008) and Romans et al. (2007), where women reported more anxious and somatic symptoms than men. Moreover, Andersen & Teicher (2008) describe in their review quite similarly that females more often experience a subtype of depression associated with anxiety, fatigue, and sleep or appetite disorders.

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