NEW YORK (Reuters Health) - Antidepressants are sometimes used for premenstrual syndrome (PMS), but a woman's specific symptoms may be key in whether the medications offer any help, a new study suggests.
Researchers found that of 447 women in clinical trials testing sertraline (Zoloft) for PMS, those with "mixed" symptoms -- multiple physical and psychological symptoms -- were the most likely to see an improvement.
In contrast, women with mainly physical PMS symptoms got little help, unless they had severe bloating or breast tenderness.
Many women have symptoms like bloating, breast tenderness, headache and emotional stress shortly before their menstrual periods. Often, simple fixes like diet changes, exercise and over-the-counter painkillers are enough to manage the symptoms.
But for some, PMS is severe enough to disrupt their daily lives, and antidepressants known as selective serotonin reuptake inhibitors (SSRIs) may be prescribed.
Studies have found that the antidepressants can help some women with PMS or premenstrual dysphoric disorder (PMDD), a severe form of PMS thought to affect a small percentage of women.
But about 40 percent of women who try an SSRI do not see a benefit.
"There's an enormous range of PMS symptoms, and an enormous range in how severe they are," said Ellen W. Freeman, a research professor of obstetrics and gynecology at the University of Pennsylvania in Philadelphia who led the new study.
These findings, she told Reuters Health, suggest that women whose symptoms are primarily physical are unlikely to get much help from an SSRI.
Besides sertraline, other SSRIs approved for treating PMDD include fluoxetine (Sarafem) and paroxetine (Paxil). (Sarafem is a repackaged form of Prozac, marketed specifically for PMDD.)
No SSRI is approved for treating PMS, said Freeman, who has received funding from antidepressant manufacturers. But doctors are allowed to prescribe the medications for PMS symptoms, and clinical trials have included not only women with PMDD, but more-severe PMS symptoms as well.
The current findings, published in the journal Obstetrics & Gynecology, are based on a second look at three of those clinical trials.
Freeman's team focused on 447 women with PMS or PMDD who were randomly assigned to take either sertraline or an inactive placebo.
The majority of women in the study had the "mixed" subtype of PMS or PMDD -- meaning they had significant physical and psychological symptoms.
And it turned out that those women stood the greatest chance of benefiting from the antidepressant, Freeman's team found. Almost two-thirds reported a 50 percent improvement in their symptoms over three menstrual cycles, compared to 42 percent of the women getting the placebo.
Women with mixed symptoms essentially had the most severe PMS, because they had the greatest number of significant symptoms, Freeman explained.
On the other hand, sertraline was less effective for women with primarily physical symptoms (which included 29 percent of the PMS group, and only one woman in the PMDD group).
Of those women, just over half of those on the antidepressant had a 50 percent drop in their symptoms, versus 38 percent of women in the placebo group -- a difference that could easily have been due to chance.
When Freeman's team focused on specific symptoms, they found that on average, all psychological symptoms were more likely to improve on the antidepressant versus the placebo.
But most physical symptoms -- including headache, fatigue, cramps and body aches -- did not get better. The exceptions were severe breast tenderness and bloating.
"The physical symptoms seemed to truly not respond, unless they were severe breast tenderness or bloating," Freeman said.
She suggested that when women are looking for treatment for PMS, they talk with their doctors about exactly what the main symptoms are, and how severe they are.
"If the symptoms are predominately physical, it seems unlikely that an SSRI will help," Freeman noted.
Since the study looked only at sertraline, it's not possible to say for sure whether the findings would hold true for other SSRIs. But that's likely to be the case, Freeman said.
As with any medication, she added, a woman has to balance the likelihood of benefit with an SSRI against the risks of side effects.
Potential side effects of the medications include headache, nausea, sleep problems and sexual side effects. The drugs have also been linked to an increased risk of suicidal behavior in teenagers and young adults.
Birth control pills are another option for treating more-severe PMS symptoms. Freeman said that future studies should see whether women with different symptom types respond differently to the Pill as well.
One of Freeman's colleagues on the study has received research funding from Pfizer Inc., which markets Zoloft. Freeman has received funding from several other drugmakers.
SOURCE: bit.ly/vbuACo Obstetrics & Gynecology, December 2011.