Intrusive thought
Antidepressants which have been shown to be effective in treating OCD include fluvoxamine (trade name Luvox), fluoxetine (Prozac), sertraline (Zoloft), paroxetine (Paxil), citalopram (Celexa), and clomipramine (Anafranil). Although SSRIs are known to be effective for OCD in general, there have been fewer studies on their effectiveness for intrusive thoughts. A retrospective chart review of patients with sexual symptoms treated with SSRIs showed the greatest improvement was in those with intrusive sexual obsessions typical of OCD. A study of ten patients with religious or blasphemous obsessions found that most patients responded to treatment with fluoxetine or clomipramine. Women with postpartum depression often have anxiety as well, and may need lower starting doses of SSRIs; they may not respond fully to the medication, and may benefit from adding cognitive behavioral or response prevention therapy.
Treatments for PTSD
Antidepressants are widely used in the treatment of PTSD and have consistently shown efficacy, though the magnitude of improvement is often modest. The most popular types of antidepressants are SSRIs, atypical antidepressants, tricyclic antidepressants (TCAs), and monoamine oxidase inhibitors (MAOs). SSRI are most often used as they are considered safer than TCAs and MAOIs. To date, only sertraline and paroxetine carry FDA approval for PTSD, though in general, all SSRIs seem similarly effective. These medications appear to be helpful across all PTSD symptoms. According to the APA Practice Guidelines, "SSRIs have proven efficacy for PTSD symptoms and related functional problems".