. Author manuscript; available in PMC: 2020 May 1.

Published in final edited form as: Behav Sleep Med. 2017 Aug 31;17(3):327–341. doi: 10.1080/15402002.2017.1357119

Table 2. Means or Percentages of Study Variables as a Function of Self-Medication for Sleep at Time 1.

Variable	Non-Sleep Aid Users at Time 1 (75%; n = 128)	Sleep Aid Users at Time 1 (25%; n = 43)	Group Comparison Test Statistics
Time 1 Variables (N = 171)
Male Sex (vs. Female)	27%	44%	χ²(1) = 4.23^*
Age (years)	18.77 (1.03)	19.49 (1.96)	t(169) = 2.29^*
Legal Drinking Status	9%	23%	χ²(1) = 6.42^*
Depression/anxiety	3.50 (2.74)	4.09 (2.65)	t(169) = 1.24
Average Sleep Duration (hours)	8.05 (0.98)	7.76 (1.68)	t(163) = -1.04
Difference WE/WD bedtime (hours)	2.17 (1.08)	2.08 (1.22)	t(163) = -0.43
Morning/Evening Preference	47.18 (7.53)	45.70 (7.31)	t(169) = -1.13
Insomnia Severity	8.35 (5.04)	10.84 (6.31)	t(169) = 2.62^**
Pre-Sleep Arousal	32.23 (9.99)	36.72 (12.79)	t(169) = 2.37^*
Alcohol Frequency	3.76 (0.95)	4.23 (1.00)	t(169) = 2.79^**
Negative Drinking Consequences	9.39 (9.74)	17.49 (14.45)	t(169) = 3.42^**
Time 2 Variables (N = 157)
Sleep Aid Users	78% (n = 122)	22% (n = 35)	—
Insomnia Severity	6.82 (4.75)	9.40 (6.58)	t(155) = 2.16^*
Alcohol Frequency	3.65 (1.05)	3.94 (1.08)	t(155) = 1.46
Negative Drinking Consequences	9.63 (12.92)	20.7 (20.62)	t(155) = 3.02^**

Note. WE/WD = weekend versus weekday. Significant group differences at p < .05 are highlighted in bold font.

p < .05.

^**

p < .01.