First and foremost, living in a single-parent household is extremely stressful–both for children and for the solo parent. Such households lack the “multi-parent dynamic” that often helps defuse in-house conflict. As a result, otherwise simple child-rearing issues and disputes (about chores or grades or other family matters) can simmer and fester, rather than resolve. This baseline stress is often made worse as the single-parent household has to absorb stress spilling over from custody issues or conflicts with the non-custodial parent or other family.
Single mothers absorb the brunt of this stress. For example, the Centers for Disease Control has found that single parents are more likely to endure poor sleep, with the worst of that falling on single moms. Barely 50% of solo mothers get at least 7 hours of sleep each night. They have twice as much trouble falling asleep (compared to married moms), and more than half of all single mothers regularly wake up feeling exhausted.

Many single mothers struggle with social isolation, social stigma, and guilt. Research has repeatedly shown that this results in higher rates of both physical and mental health disorders for single mothers. Single mothers have been found to have higher risk for depression and other mood and anxiety disorders. Similarly, children raised in single-mother households are at heightened risk for substance abuse, depression, anxiety, and both outwardly- and inwardly-focused destructive behaviors and disorders.