Variables associated with perceived sleep disorders in methadone maintenance treatment (MMT) patients

To characterize sleep disorders in methadone maintenance treatment (MMT) patients, we evaluated sleep quality of 101 non-selective patients from our MMT clinic in Israel between July, 2003 and July, 2004 by using the self-report questionnaire Pittsburgh Sleep Quality Index (PSQI). Patients' urine tests were analyzed for methadone metabolite, opiates, benzodiazepine, cocaine, cannabis and amphetamines. Their urine results for drug abuse throughout the months prior to filling in the questionnaire and their maintenance methadone doses were recorded. Drug abuse was defined by at least one positive urine test. Methadone serum levels were available in 55 patients, assessed by Gas Chromatography Mass Spectroscopy. The patients' self-reported chronic pain questionnaires and their diagnosed psychiatric disorders were analyzed. Out of the 101 study patients, 78.2% were male, 52.5% had psychiatric disorders, 46.5% reported having chronic pain and 46.5% had positive urine for benzodiazepine. The mean daily methadone dose was 157+/-52.9 mg. The mean PSQI score was 9+/-4.8 (75.2% had scores >5 indicating "poor sleepers"). PSQI scores were higher in patients with positive urine for benzodiazepine, chronic pain and psychiatric disorders and they correlated with years of opiate abuse before admission to MMT, and with the methadone dose (r=0.48, p<0.0005). The latter two also correlated with each other. The PSQI was not correlated with duration in MMT, gender, age, abuse of opiates, cannabis or cocaine. We concluded that sleep disorders should be evaluated and treated among MMT patients, particularly in those with psychiatric disorders, benzodiazepine abuse, chronic pain and high methadone dose.