Lonely in Depression

Depression (symptom severity)

Montgomery-Åsberg Depression Rating Scale (MADRS) (10 Items, each item rated 0-6 points, minimum 0 points, maximum 60 points, higher scores indicate greater severity of depressive symptoms)

Loneliness

3 Item UCLA Loneliness Scale (3-Item UCLA) (3 items, each item rated 1-3 points, minimum 3 points, maximum 9 points, higher scores indicate greater loneliness)

Depression

Patient Health Questionnaire, 9-Item Depression Scale (PHQ-9) (9 Items, each item rated 0-4 points, minimum 0 points, maximum 27 points, higher scores indicate greater severity of depression)

Loneliness

6-Item short scales for Loneliness, De Jong Gierveld Loneliness Scale (6-Item DJGLS) (6 Items, each item rated 1-3 points, before the total score is calculated, the items are dichotomized, thus resulting in a sum score ranging from 0 to 6, wherein scores of 0-1 indicate no loneliness, 2-4 indicate moderate loneliness, and 5-6 indicate severe loneliness)

Social Support

Fragebogen zur Sozialen Unterstützung (F-SoZ-U 14) (14 Item shortend form, each item rated 0-4 points, minimum 0 points, maximum 56 points, higher total scores indicating higher levels of perceived social support)

Inpatient treatment duration

in days

Quality of life in self-report

World Health Organization-Five Well-Being Index (WHO-5) (5 Items, each item rated 0-5 points, minimum 0 points, maximum 25 points, the total score (0-25) is transformed to a scale ranging from 0 to 100, with scores ≤50 indicating diminished well-being and higher scores representing higher well-beeing)

Social Network measure (newly designed for this study)

As there is no culture and language adapted version of a social network indice available an adapted and German-translated version is used to capture participants' social interaction partners during the prior two weeks. The questionnaire was newly developed, with item content informed by existing validated scales (Cohen Social Network Index (SNI), Lubben Social Network Scale (LSNS), Berkman - Social Network/Integration). Via the use of a yes/no response format, participants indicated whether they had personal or telephone contact with each of the following: (1) spouse or partner, (2) own children, (3) parents or parent-like figures, (4) other relatives (e.g., siblings, uncles, or aunts), (5) friends, (6) neighbors, (7) colleagues, (8) people known through voluntary activities, (9) in-laws (parents, sons, or daughters-in-law), and (10) members of their social group (e.g., community, congregation, sports, or music clubs). Higher total scores indicate greater social connectedness.

Blood markers (metabolic, LDL)

LDL cholesterin \[mg/dl or mmol/l\], higher values (\> 100 mg/dl or \> 2.6 mmol/l) represent unfavorable metabolic risk

Blood markers (metabolic, HDL)

HDL cholesterin \[mg/dl or mmol/l), \< 40 mg/dl men and \< 50 mg/dl women represents unfavorable metabolic risk, ≥ 40 mg/dl men ≥ 50 mg/dl women acceptable, ≥ 60 mg/dl protective

Blood markers (metabolic, HbA1c)

HbA1c \[%\], higher values (\> 5.7%) represent unfavorable metabolic risk

Blood markers (Sphingolipid metabolism)

Sphingolipid metabolism enzyme activity of secretory acid sphingomyelinase (S-ASM) \[nmol/mL/h/µL\], higher leveles represent more inflammation/apoptosis enzyme activity of neutral acid sphingomyelinase (N-ASM) \[nmol/mL/h/µL\], higher levels represent cellular stress/apotosis Ceramide \[nmol/L\], higher levels represent more inflammation/apoptosis