Escitalopram administered in the luteal phase exerts a marked and dose-dependent effect in premenstrual dysphoric disorder.

This is the first placebo-controlled trial evaluating the efficacy of the selective serotonin reuptake inhibitor (SSRI), escitalopram, in the treatment of premenstrual dysphoric disorder (PMDD). Women with PMDD (intention-to-treat population, n = 151) were treated intermittently for 3 months, during luteal phases only, with 10 mg/d escitalopram, 20 mg/d escitalopram, or placebo. Escitalopram was found to exert a marked and a dose-dependent symptom-reducing effect, 20 mg/d being clearly superior to 10 mg/d. Although the primary outcome parameter, that is, the sum of the symptoms irritability, depressed mood, tension, and affective lability, was decreased by 90% with 20 mg/d escitalopram, the effect of active treatment on breast tenderness, food craving, and lack of energy was more modest and not significantly different from that of placebo; this outcome supports our previous assumption that the former symptoms are more inclined to respond to intermittent administration of an SSRI than are the latter. Although the placebo response was high, the difference between the placebo group and the 20-mg/d escitalopram group with respect to the percentage of subjects displaying 80% or greater reduction in the rating of the cardinal symptom of PMDD, that is, irritability, was considerable: 30% versus 80%. Adverse events were those normally reported in SSRI trials, such as nausea and reduced libido, and were not more common in patients given 20 mg/d of escitalopram than in patients given the lower dose. This study supports the usefulness of escitalopram for the treatment of PMDD and sheds further light on how different components of this syndrome are differently influenced by intermittent administration of an SSRI.

Placebo-controlled trial comparing intermittent and continuous paroxetine in premenstrual dysphoric disorder.

Serotonin reuptake inhibitors (SRIs) do not have to be administered continuously to be effective for premenstrual dysphoric disorder (PMDD), but can be given during luteal phases only. This is of practical importance, but also of theoretical interest since it suggests that the onset of action of SRIs is shorter in PMDD than in, for example depression. In this study, both continuous and intermittent SRI administration was compared with placebo, with the special purpose of analyzing if different PMDD symptoms respond differently depending on the treatment regimen. To this end, women meeting slightly modified DSM-IV criteria for PMDD (mean+/-SD age, 37+/-6.3 years) were treated for three menstrual cycles with paroxetine continuously, paroxetine during the luteal phase only, or placebo, the population completing at least one treatment cycle comprising 55-56 subjects per group. Continuous treatment with paroxetine reduced premenstrual symptoms effectively with a response rate of 85%. The effect size was highest for irritability (1.4) and lowest for lack of energy (0.5). Intermittent treatment was as effective as continuous treatment in reducing irritability, affect lability, and mood swings, but had a somewhat weaker effect on depressed mood and somatic symptoms. The study indicates that the response rate when treating PMDD with SRIs is high, and that irritability is a key target symptom. Symptoms such as irritability, affect lability, and mood swings appear to be more inclined to respond rapidly to SRIs, enabling intermittent treatment, than are, for example, the somatic symptoms.

Heart rate variability in premenstrual dysphoric disorder.

Measuring heart rate variability (HRV) is a way to assess the autonomic regulation of the heart. Decreased HRV, indicating reduced parasympathetic tone, has previously been found in depression and anxiety disorders. The objective of this study was to assess HRV in women with premenstrual dysphoric disorder (PMDD). To this end, time domain variables and frequency domain variables were assessed in 28 women with PMDD and in 11 symptom-free controls during both the symptomatic luteal phase and the non-symptomatic follicular phase of the menstrual cycle. Two variables reflecting vagal activity in the time domain, the root mean square of differences of successive normal RR intervals (rMSSD) and standard deviation of normal RR intervals (SDNN) were lower in PMDD patients, but this difference was statistically significant in the follicular phase only. The most important vagal measure in the frequency domain, supine high frequency (HF), also appeared lower in PMDD subjects during the follicular phase. It is suggested that PMDD may be associated with reduced vagal tone compared to controls and that this difference is most apparent in the non-symptomatic follicular phase of the menstrual cycle.