SEATTLE—Features of obsessive–compulsive personality disorder (OCPD) do not appear to affect the response to cognitive behavioral therapy for insomnia (CBT-I) among people with chronic insomnia and hypnotic dependence, according to research presented at the 29th Annual Meeting of the Associated Professional Sleep Societies. At one year after CBT-I, however, insomnia relapse may be more likely among people with OCPD than among people without OCPD.
The personality disorder may make people with insomnia more vulnerable to challenges in their sleep environments, said Sarah Emert, a doctoral student in clinical health psychology at the University of Alabama in Tuscaloosa. OCPD may be a predisposing factor for chronic insomnia, as well as a factor that leads to relapse, she added.
Chronic insomnia has been associated with cognitive and emotional hyperarousability, increased neuroticism, increased perfectionism, decreased agreeableness, and decreased conscientiousness. In addition, chronic insomnia is often comorbid with Cluster C personality disorders, especially OCPD.
Comparing Sleep and Personality Variables
To determine whether specific features of OCPD are associated with response to CBT-I, Kenneth L. Lichstein, PhD, Professor of Psychology at the University of Alabama and principal investigator, and colleagues conducted a randomized controlled trial of patients with chronic insomnia and hypnotic dependence. Eligible participants were between ages 21 and 69 and met ICSD-2 criteria for insomnia. They used hypnotics at least four nights per week for six months or longer, wanted to quit using the drugs, and were unable to do so on their own. Exclusion criteria included sleep-disordered breathing, sleep-related movement disorders, seizures, high levels of caffeine or nicotine use, and use of other drugs that affect sleep.
Participants completed eight weekly sessions of CBT-I and simultaneously stopped taking hypnotics. They completed two weeks of sleep diaries and underwent two nights of polysomnography (PSG) at baseline, post-treatment, and one-year follow-up.
The researchers obtained information about participants’ personalities using the Structured Clinical Interview for DSM-IV Axis II Personality Disorders. Megan E. Petrov, PhD, Assistant Professor at Arizona State University in Phoenix and the lead investigator on this research project, and colleagues compared participants’ personality features with their sleep outcomes, including Insomnia Severity Index score, PSG-derived total sleep time, sleep efficiency, sleep onset latency, wake after sleep onset, stage percentages of sleep, and sleep diary values.
A mixed-effects model helped the investigators examine the interaction between OCPD status and time across the trial on each of the sleep variables. The researchers adjusted the data for age, gender, number of insomnia nights per week, insomnia duration, and hypnotic use duration.
Differences Emerged One Year After Treatment
In all, 27 participants completed the study, and nine of them met initial clinical criteria for OCPD. Full diagnostic interviews were not conducted. The majority of participants were female. At baseline, mean insomnia duration was 14.6 years, mean number of insomnia nights per week was 5.1, and mean years of medication use was 3.0. The number of nights with insomnia per week was lower among partcipants with features of OCPD at baseline, whereas the number of years of medication use was higher.
Data analysis found no significant differences between patients with and without features of OCPD in PSG, sleep diaries, and Insomnia Severity Index immediately following CBT-I treatment. At one year post treatment, however, participants with and without OCPD did have significant differences in several variables. Total sleep time, sleep efficiency, and percentage of REM sleep were lower at one year for patients with features of OCPD, compared with those without. Time spent awake, sleep-onset latency, and percentage of Stage 2 sleep were greater at one year among patients with OCPD, compared with those without.
In patients with OCPD and insomnia, CBT-I is worth pursuing “because these patients still had no differences in the Insomnia Severity Index score and sleep diary values, compared with patients without OCPD features,” said Dr. Petrov. “Therefore, their perception of their sleep at one year was improved. It was only when presented with the challenge of overnight PSG in the laboratory that you see the differences in two nights of objectively measured sleep.”
—Erik Greb