A depressed father will tune out the kids or limit his interactions with them. He may also interpret a child's misbehavior more harshly. The more overwhelmed a mother feels, the less capably she will handle any child situation. This excerpt is from How To Say It to Your Kids by Dr. Paul Coleman. Since dissatisfied couples are 25 times more likely to become depressed than are happy couples, it is important for a depressed person to look closely at the state of the marriage.
Antidepressant medications can be very helpful.
Support from other adults is also necessary when a person feels overwhelmed. Single parents have a very difficult task because they are on the job constantly. You find an expensive item on the ground and keep it instead of trying to locate the owner. Your car is a mess. The top of your dresser is a mess.