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.
Cause of obsessive-compulsive disorder
Data obtained from this research suggests that three brain areas are involved with OCD: the orbitofrontal cortex (OFC), the anterior cingulate cortex (ACC), and the head of the caudate nucleus. Several studies have found that in patients with OCD, these areas: (1) are hyperactive at rest relative to healthy control; (2) become increasingly active with symptom provocation; and (3) no longer exhibit hyperactivity following successful treatment with SRI pharmacotherapy or cognitive-based therapy. This understanding is frequently cited as evidence that abnormality in these neuroanatomical regions may cause OCD.