Table 1.

Study demographics

	All		High computer use1		High mobile phone use1
	n = 32		n = 28		n = 20
	Freq	%	Freq	%	Freq	%
Gender
Women	16	50	13	46	12	60
Men	16	50	15	54	8	40
Study background
IT	25	78	25	89	13	65
Medical doctor or nurse	7	22	3	11	7	35
Upper quartile regular exposure in 2004
Computer2	21	66	21	75	10	50
Mobile phone3	14	44	10	36	14	70
Reported mental symptoms in 20054
Three symptoms	28	88	24	86	17	85
Two symptoms	4	12	4	14	3	15
Psychiatric diagnosis in present study	12	38
Mild - moderate depression	6	19
Anxiety disorder UNS	4	12
Mixed anxiety and depression	1	3
Mood syndrome UNS	1	3
Reported connection between subjective mental symptoms and IT use in 2005	10	31	10	36	6	30

freq = frequency

¹Inclusion criteria for the groups were a reported minimum exposure in the upper half of the larger cohort in 2004 of the technology in question. Lowest exposure in High computer use group was for women 10 and for men 26 hours per week. Lowest exposure in High mobile phone use group was for women 8 and for men 7 calls or SMS messages per day. Sixteen subjects participated in both groups.

²For women: > 20 hours per week. For men: > 40 hours per week.

³For women: > 11 calls or SMS messages per day. For men: > 12 calls or SMS messages per day.

⁴Mental symptom items were: Have you continuously, for more than 7 days, during the past 12 months experienced: 1) stress (defined as a situation in which a person feels tense, restless, nervous or anxious, or is unable to sleep at night because his/her mind is troubled)? (adapted from the QPS Nordic [63]) 2a) little interest or pleasure in doing things, or 2b) feeling down, depressed, or hopeless? (adapted from Prime-MD [64]) 3a) difficulties falling asleep, or 3b) repeated awakenings with difficulties going back to sleep (adapted from the Karolinska Sleep Questionnaire [65])? All items had been adapted to reflect a prolonged state.