They feel alone and uncared for. They rehash unhappy events from the recent and distant past that are relevant only to the depression. Sleepless nights increase fatigue. Dishes pile up in the sink. The house is cluttered.
Office work remains unfinished.
Extra activities are abandoned for lack of energy. Body posture changes. The shoulders sag. Gait is slowed and shuffling. The face and voice are sad even when the person smiles.