Objective. The aim of the present study is to analyse the frequency of the different types of insomnia (early, middle and late insomnia) in a sample of patients with Obsessive-Compulsive Disorder (OCD). It also intends to determine whether the presence of a comorbid depressive disorder influences frequency and type of insomnia. Methods. All patients with a primary diagnosis of OCD, consecutively referred to the Mood and Anxiety Disorder Unit, Department of Neuroscience, University of Turin, from January 2000 to December 2004, were recruited. Frequency and severity of the different types of insomnia were evaluated on the basis of the Hamilton Depression Rating Scale (HDRS) specific items scores (item 4-5-6). Aim. Two different analyses were performed with regard to insomnia: 1) OCD patients without any comorbid depressive disorder vs OCD patients with any comorbid depressive disorder; 2) OCD patients without any comorbid depressive disorder vs OCD patients with a comorbid Major Depressive Episode (MDE). Results. The sample included 141 patients. 58.2% suffered from any type of insomnia, especially early insomnia (46.1%). The presence of any comorbid depressive disorder increased the frequency of insomnia up to 67.7% (p=0.041). The presence of a comorbid MDE significantly increased the frequency of late insomnia up to 33.3% (p=0.021). Conclusions. Insomnia, especially the early one, is a common symptom in OCD patients with or without comorbid depressive disorders. Late insomnia is typical of OCD with comorbid major depression.
