Premenstrual syndrome (PMS) affects millions of women during their reproductive years. The disorder presents with emotional, cognitive, behavioural, and somatic symptoms during the final premenstrual phase and subsiding a few days after menses begins. About 75% of women of reproductive age experience a mild form of PMS (Campbell, Peterkin, O'Grady, \& Sanson-Fisher, 1997). The more severe form of PMS, premenstrual dysphoric disorder (PMDD; American Psychiatric Association (APA), 1994) is considered to affect up to 8% of women of reproductive age. This severe form is associated with severe disruptions in normal functioning in work, family, or social relationships (Halbreich, Borenstein, Pearlstein, \& Kahn, 2003). The defining characteristics of both-PMS and PMDD- are the cyclic pattern of symptoms, which must be confirmed by prospective daily self ratings of symptoms (PMS-Diary) over two consecutive menstrual cycles (American College of Obstetricians and Gynecologists (ACOG), 2000). PMS and PMDD differ according to the number, severity, duration, and quality of symptoms.
As a first-line intervention, the ACOG suggests pharmacotherapy, in particular selective serotonin reuptake inhibitors (SSRIs; ACOG, 2000). However, the side effects of SSRIs are intolerable to many women, leading to high rates of withdrawal from treatment (Busse et al., 2009; Dimmock, Wyatt, Jones, \& O'Brien, 2000). Thus, cognitive behavioural treatments (CBT) have been suggested as an additional treatment approach (Busse et al., 2009). First studies showed promising results for CBT interventions for PMS (Busse et al., 2009; Hunter et al., 2002). However, too few randomized controlled trials have carefully investigated the efficacy of CBT for PMS.
The aim of the current study is thus to develop a CBT-oriented self-help treatment programme for women suffering from PMS or PMDD. The treatment programme consists of psychoeducation (e.g., information about PMS/PMDD and its aetiology), cognitive strategies (e.g., assessing and restructuring dysfunctional cognitions), and suggestions for lifestyle changes (e.g., sports, balanced diet, relaxation). The programme is internet-delivered (iCBT) and participants work on different chapters for eight weeks in a row. In addition to written information, participants receive e-mail feedback from a psychologist on a weekly basis. Participants are required to have sufficient knowledge of German in order to be able to read the treatment materials. After a careful diagnostic assessment (including two months symptom diary), eligible patients are randomly assigned either to the treatment group or a waitlist control group. Participants assigned to the waitlist receive the treatment after the end of the waiting period (eight weeks). Follow-up assessments take place six months after the end of the treatment.
