| very | 9 | degree |
| in regulating mood | 9 | other |
| in increasing the amount of brain | 8 | other |
| serotonin → be → important | 42 |
| serotonin → be → essential | 25 |
| serotonin → be → vital | 13 |
| serotonin → be → important chemical | 11 |
| serotonin → be → crucial | 10 |
| serotonin → be → critical | 9 |
| serotonin → be → vital chemical | 3 |
| negative | neutral | positive |
| 0.070 | 0.525 | 0.405 |
| Raw frequency | 113 |
| Normalized frequency | 0.677 |
| Modifier score | 0.500 |
| Perplexity | 55.819 |