Reduced Melatonin levels in OCD

From lef.org article on OCD:

"An additional angle of interest involves the pineal hormone melatonin. Melatonin is well known to induce sleep in humans. At least one study has shown that people with OCD tend to have depressed melatonin levels, along with elevated levels of the stress hormone cortisol (Monteleone P et al 1995)."