Table 2.
Circadian measures during acute substance use
| Study | Substance | Sample | Methods | Key Results | Limitations |
|---|---|---|---|---|---|
| Danel et al, 2001 (41) | Alcohol | 9 healthy young adult males (age = 23.3 ± 2.9 yr; range 21–30) | All participants underwent a 26-h alcohol session and a 26-h placebo session, separated by 2-5 weeks. Alcohol administered orally during waking hours and intravenously during sleep to maintain a target BAC between 0.5 and 0.7 g/l throughout the session. Core body temperature (CBT) measured every 20 min throughout 26-h session. |
Lower CBT during afternoon (1220-1400) and higher CBT during early morning (0300-0820) relative to placebo. | Sleep/wake schedule prior to study was not controlled |
| Danel and Touitou, 2006 (40) | Alcohol | 11 healthy young adult males (age = 23.3 ± 2.9 yr; range 18-30) | All participants underwent a 26 h alcohol session and a 26 h placebo session. Alcohol administered orally during waking hours and intravenously during sleep to maintain a BAC between 0.29 and 0.78 g/l throughout the session. Blood samples collected from 1200 on day 1 until 1500 on day 2. Lux < 50 |
No differences in melatonin levels in group comparisons. Apparent phase delay in the melatonin profiles of six out of 11 participants. |
Reported statistical analysis may have missed transient suppression in melatonin levels. Poor ecological validity of alcohol administration paradigm. |
| Devaney et al, 2003 (42) | Alcohol | 8 moderate drinker adults (4 females, age = 25.1 ± 6.0 yr; range 18-40, M = 4.3 ± 2.3 standard drinks/day) reporting a pre-study average of two drinking days per week with 4.3 ± 2.3 (M ± SD) drinks per occasion | Compared alcohol consumption at 1300 and 1800 (sessions separated by > 1 week). Target peak BAC of 1.0 g/l. Core body temperature measured every minute starting 1 h before consumption and ending at 0900 the following morning. |
Effects depended on time-of-day of consumption. Both session times were associated with lower CBT throughout the sleep period (2330-0830). The 1300 session was also associated with higher CBT for 5-9 hours post-consumption. |
Sleep/wake schedule prior to study was not controlled |
| Ekman et al, 1993 (37) | Alcohol | 9 healthy medical students (5 females, aged 21-23 years). No alcohol for at least 1 week prior to study No medications or smoking during 3-week study. |
Single oral dose of 0, 0.5, or 1.0 g/kg alcohol between 1900-1945. Within-participant comparison, with doses administered at 1-week intervals. Collected plasma samples at 1800, 2000, 2200, 2400, 0100, 0200, 0400, and 0700. Collected urine from 1900-2400 and 2400-0700 for urinary MT excretion. Lights on until 2300 when participants sent to bed; < 2 lux from 2300-0700. |
Both alcohol doses associated with lower plasma melatonin levels; 41 % reduction for both at 2400, and 33 and 18% reduction at 0100 and 0200, respectively, for the 1.0 g/kg dose. No differences in urinary MT levels. |
High light levels <2300. Sleep/wake schedule prior to study was not controlled, light exposure history was unknown, and circadian phase was not assessed (unknown circadian time of administration). |
| Plenzler et al., 1996 (39) | Alcohol | 10 healthy adult males (mean age = 23.6 yr) | All participants tested on three nonconsecutive nights separated by at least 48 hours. In random order, received alcohol (0.8 g/kg dose) at either 2005 or 2305, or received placebo beverage. Saliva collected hourly from 2000-0200. Lux ≤ 100 throughout collection. |
No differences in saliva melatonin levels at either dose. | Small collection window may have missed delayed melatonin suppression. |
| Rodjmark et al, 1993 (36) | Alcohol | 7 healthy non-obese participants (4 females, age = 29 ± 1 yr) All unmedicated. |
Experiment A-C: Alcohol administered at one of two doses (0.34 g/kg in A, 0.52 g/kg in B) at 1800, 2000, and 2200. Water was administered at same time points in Experiment C. Serum samples collected every 2 hours from 1800-0800. Collected urine from 2200-0700 for urinary melatonin excretion. For Experiments A-C: Lux 280-430 until 2300 when participants sent to bed. A 25W red light was used from 2300-0700. |
Only higher alcohol dose (Exp B) was associated with lower serum melatonin levels: 20% reduction in total melatonin secretion relative to control group (Exp C). No differences in urinary melatonin levels. |
High light levels <2300; unreported lux 2300-0700 (although red light likely to exert minimal suppression). Sleep/wake schedule prior to study was not controlled and light exposure history was unknown. Small sample sizes and between-group comparison. |
| Rupp et al, 2007 (31) | Alcohol | 29 healthy young adults (20 females, age = 22.6 ± 1.2 yr; range 21-25) | All participants underwent a placebo night and an alcohol night, counterbalanced and separated by 5-7 nights. Both nights included 30-minute beverage session ending 1 h before bed. Alcohol dose of 0.54 and 0.48 g/kg for men and women, respectively. Saliva samples collected every ~30 min starting 5 h before and ending 4.5 h after habitual bedtime. Lux < 20 throughout collection. |
Alcohol consumption associated with lower salivary melatonin levels (19 and 15%, respectively, relative to placebo) at 140 and 190 minutes post-consumption. No sex effects. No effects on sleep as based on PSG measures of subset (n = 8) of sample. |
Sleep only measured via PSG on subset of sample. |
Notes: All times provided in military time (e.g., 1900 = 7 PM)
Abbreviations: CBT = core body temperature; DLMO = Dim light melatonin onset; 6-SM = 6-sulfatoxymelatonin