Table 1.
Sociodemographic and illness-specific data of study participants.
| Individuals with BD (n = 48) |
HC (n = 48) | Statistics | p | Effect Size | |
|---|---|---|---|---|---|
| Age [years] | 51.59 (±11.13) | 51.71 (±8.47) | t (87,14) = −0.06 | 0.951 | d = 0.01 |
| Sex | 37.5% male 62.5% female |
37.5% male 62.5% female |
X2 = 0 | 1.00 | |
| BMI [kg/m2] | 25.33 (±5.24) | 23.60 (±3.42) | t (94) = 1.91 | 0.059 | d = 0.39 |
| Smoking status | 27.1% no 47.9% yes 25.0% ex-smoker |
68.8% no 18.8% yes 12.5% ex-smoker |
X2 = 16.82 | <0.001 ** | η2 = 0.419 |
| TRP [μg/mL] | 9.54 (±1.64) | 11.06 (±1.69) | F (1,91) = 18.26 | <0.001 ** | η2 = 0.167 |
| KYN [μg/mL] | 0.35 (±0.10) | 0.38 (±0.14) | F (1,91) = 2.070 | 0.154 | η2 = 0.022 |
| KYN/TRP*1000 ratio | 38.11 (±14.50) | 34.86 (±11.97) | F (1,91) = 0.99 | 0.321 | η2 = 0.011 |
| KYNA [ng/mL] | 9.02 (±4.76) | 10.25 (±8.09) | F (1,91) = 1.26 | 0.264 | η2 = 0.014 |
| 3-HK [ng/mL] | 42.46 (±2.84) | 44.40 (±13.48) | F (1,91) = 0.86 | 0.356 | η2 = 0.009 |
| QA [ng/mL] | 142.62 (±15.13) | 158.73 (±45.89) | F (1,91) = 4.91 | 0.029 * | η2 = 0.051 |
| QA/KYNA ratio | 24.01 (±20.93) | 22.54 (±14.01) | F (1,91) = 0.24 | 0.623 | η2 = 0.003 |
| 5-HTP [ng/mL] | 87.90 (±29.49) | 69.93 (±34.48) | F (1,91) = 5.95 | 0.017 * | η2 = 0.061 |
| 5-HT [ng/mL] | 319.25 (±168.83) | 260.74 (±167.97) | F (1,91) = 3.55 | 0.063 | η2 = 0.038 |
| MLT [pg/mL] | 11.44 (±6.53) | 11.89 (±5.82) | F (1,91) = 0.09 | 0.764 | η2 = 0.001 |
Note. Abbr.: BD = bipolar disorder; BMI = body mass index; HC = healthy controls; KYN = kynurenine; KYNA = kynurenic acid; QA = quinolinic acid; TRP = tryptophan; 3-HK = 3-hydroxykynurenine; 5-HTP = 5-hydroxytryptophan; 5-HT = serotonin; MLT = melatonin. Significant results are presented in bold letters; * p < 0.05, ** p < 0.01. Data are reported as means (±standard deviations).