Cognitive functioning in opioid-dependent patients treated with buprenorphine, methadone, and other psychoactive medications: stability and correlates

Table 3 Group demographics in sample II

	Buprenorphine or Buprenorphine/ Naloxone (n= 18)	Methadone (n= 18)	Group or time point comparison p-values
Age, years at T1 (M ± SD)	30 ± 8	32 ± 8	ns
Sex: females/males, %	28/72%	33/67%	ns
Verbal IQ ^a (M ± SD)	101 ± 8	100 ± 11	ns
Education, years (M ± SD)	10 ± 2	11 ± 1	ns
Participants with early neurobehavioral problems %	33%	28%	ns
Examined in inpatient settings %
T2	6%	6%	ns
T3	11%	11%	ns
Participants with high frequency use of any substance of abuse % ^b
T2	44%	39%	ns
T3	44%	44%	ns
Participants with recent month extra doses of any opioid % ^c
T2	36%	36%	ns
T3	36%	43%	ns
Nicotine, participants using daily, %
T2	100%	100%	ns
T3	100%	100%	ns
Days in opioid substitution treatment at test (M ± SD)
T2	211 ± 19	196 ± 27	ns
T3	411 ± 43	405 ± 29	ns
Age of onset, any substance abuse (M ± SD)	16 ± 4	15 ± 3	ns
Age of onset, opioid abuse (M ± SD)	19 ± 5	19 ± 4	ns
Participants with lifetime alcohol abuse	72%	83%	ns
Years of any substance abuse at T1 (M ± SD)	15 ± 7	17 ± 7	ns
Years of alcohol abuse at T1 (M ± SD)	3 ± 4	3 ± 3	ns ^b
Years of opioid abuse at T1, years (M ± SD)	10 ± 7	12 ± 7	ns

^a Estimation based on the WAIS-R Vocabulary score.
^b High frequency = three or more days a week Alcohol use was considered heavy if it was at least mean weekly 16 portions for females and 24 portions for males. One portion was defined as 12 g of alcohol.
^c Non-prescribed doses of opioids during the recent month seen in drugs screens or admitted by the patient.