Recent findings concerning the statistical laws of behavioral organization shared between healthy humans and wild-type mice (WT) and their alterations in human depression patients and circadian clock gene (Period 2; Per2) mutant mice indicate that clock genes play functional roles in intermittent, ultradian locomotor dynamics.
In a non-psychiatric cohort of 419 Caucasians, the severity of depression was assessed prospectively during pregnancy (3rd trimester) and the postpartum period (2-3 days and 6-8 months) using the Edinburgh Postnatal Depression Scale.
In a cohort of 361 Caucasians, the severity of depression was assessed prospectively during pregnancy (third trimester) and the postpartum period (2-3 days and 6-8 months) using the Edinburgh Postnatal Depression Scale (EPDS).
Candidate genes, such as those encoding for the brain-derived neurotrophic factor (BDNF), serotonin transporter (5-HTT), and Period2 (PER2), have been associated with depression and seasonal disorders.