Compulsive hoarding
Hoarding isn't the same as collecting. The difference between the two is collectors are more likely to get possessions and valuable material in a targeted, organized and intentional way. Those who hoard often have an obsession and hardly any active planning. The mere sight of the objects may cause this. The objects do not really have any consistent theme. Collectors of objects have narrow focus on particular (or same/similar) topics. One of the signs of hoarding problems is heavy, disorganized clutter.