Premenstrual syndrome (PMS) and premenstrual dysphoric disorders (PMDD), as a severe form of premenstrual syndrome, have shown to be associated with several psychological conditions, such as reduced psychological wellbeing [1
], mood disorders, particularly depressive disorders [7
], and exacerbation of depression [15
]. There is limited research on the relationship between major depression and premenstrual symptoms from studies with large sample sizes or from population-based studies. Wittchen et al. [16
] have indicated a high comorbidity between PMDD and other mood disorders (22.9%) in a community-based study. Similar comorbidity rates were observed for PMS and major depression by Yonkers et al. [9
]. In a U.S. population-based study, it was shown that women with menstrual problems were significantly more likely to report depression [17
The temporal relationship between PMS and major depression has been investigated in several studies yielding conflicting results. Some studies have shown that women with PMS or PMDD have a higher percentage of past major depression than women without PMS or PMDD [10
], while Hurt et al. have reported contradictory results [19
]: Although the risk of late luteal phase dysphoric disorder (LLPDD) (the former term for PMDD in the DSM-III-R) was 14% higher in women with a past psychological disorder, it was not increased in women who reported to suffer from a major depression in the past [19
]. Breaux, Hartlage and Gehlert [20
] concluded in their review that based on existing research it has not been fully proven whether women with PMDD have a higher likelihood to report past major depression.
There is also some evidence that women with PMDD might be at a higher risk to develop major depression in the future than women without PMDD [20
Besides investigating the relationship between the two disorders, examination of whether and how the two disorders can be differentiated from each other is also of relevance. For PMDD, the criteria of the DSM-IV require the disturbance not to be merely an exacerbation of the symptoms of another disorder, such as major depression. Nevertheless, a clear distinction between PMDD and depression seems not always as clear as wished, and some symptoms, such as depressed mood, feelings of hopelessness, decreased interest in usual activities, concentration difficulties, lack of energy, change in appetite, hypersomnia or insomnia are included in measures for both disorders [22
]. Some authors described an overlap of symptoms such as irritability, or mood swings between severe premenstrual syndrome and depression [24
]. Others, however, emphasised that despite the intriguing similarities between PMDD and depression, they should be regarded as distinct diagnostic entities [25
]. Irritability has been described as a more prominent symptom in women with PMS or PMDD than depressed mood [12
]. Differences in the dysregulation in the stress axes in women with PMDD and in women with current or past depressive disorders also suggest the two disorders to be distinct [27
]. Results of studies about risk factors for depression or PMS suggested that the two disorders might have differing causes. In a longitudinal population-based twin study, it was suggested that genetic and environmental risk factors of premenstrual symptoms and major depression are not closely associated [28
]. Premenstrual symptoms seem to be only to a small degree or not at all influenced by familial-environmental factors [28
To our knowledge, little is known about the group of women who report both major depression and premenstrual symptoms. Comorbidity could be related to higher impairment which would make appropriate treatment for this group of women particularly relevant. Soares et al. [29
] have shown that women with PMDD and a history of depression were less educated and reported marital disruption less frequently than women with PMDD and no history of depression.
There is a paucity of data from population-based studies on the association between and the distinction of PMS and major depression, and especially knowledge about the group of women reporting to suffer from both is also limited. The first aim of this study was therefore to assess the prevalence of women reporting both major depression and premenstrual symptoms in a large population-based sample and to analyse how women with PMS and depression differ from each other. A second aim was to characterise women who report both major depression and premenstrual symptoms.