Delayed- Maturation Theory of Obsessive Compulsive Disorder
Drug treatment of OCD may be assumed to affect a proposed functional imbalance between the frontal lobes and other parts of the brain. Serotonin reuptake inhibitors, SRI, especially potent ones given at high doses over long periods of time, are often effective in the treatment of obsessive-compulsive disorder. However, a large percentage of patients do not respond to treatment with the SRI, and those who do respond often do not fully remit, which should be the standard goal of treatment in OCD. If a patient has been treated for several months and has not yet responded to treatment with several types of SRI medication, the physician should perform a careful assessment of resistant and/or residual clinical symptoms. Any comorbid conditions to determine which next-step treatment would be the most appropriate. One strategy for patients who have not responded to treatment with a SRI is to switch them to aserotonin-norepinephrine reuptake inhibitors.
Premenstrual dysphoric disorder
Several medications have received empirical support for the treatment of PMDD. Selective serotonin reuptake inhibitors (SSRIs) are the first-line medication. The U.S. Food and Drug Administration (FDA) has approved four SSRIs for the treatment of PMDD: Fluoxetine (available as generic or as Prozac or Sarafem), sertraline (Zoloft), paroxetine (Paxil), and escitalopram oxalate (Lexapro). Unlike treatments for depressive disorders, SSRIs do not need to be taken daily but instead can be taken only in the luteal phase or during PMDD symptoms. This is because those who respond to SSRIs usually experience symptoms relief within 1–2 days. Studies in rats suggest this rapid response to SSRIs is due to the elevation of the neuroactive progesterone metabolite allopregnanolone in the brain, rather than serotonin. Luteal phase dosing can be started 14 days before menses and subsequently discontinued after start of menstrual flow. Women taking SSRIs to ease PMDD generally report >50% alleviation in symptoms, which was significant improvement compared to placebo.