Getting and saving an excessive number of items, gradual buildup of clutter in living spaces and difficulty discarding things are usually the first signs and symptoms of hoarding disorder, which often surfaces during the teenage to early adult years.

As the person grows older, he or she typically starts acquiring things for which there is no immediate need or space. By middle age, symptoms are often severe and may be harder to treat.

Problems with hoarding gradually develop over time and tend to be a private behavior. Often, significant clutter has developed by the time it reaches the attention of others.

Signs and symptoms may include:

• Excessively acquiring items that are not needed or for which there's no space
• Persistent difficulty throwing out or parting with your things, regardless of actual value
• Feeling a need to save these items, and being upset by the thought of discarding them
• Building up of clutter to the point where rooms become unusable
• Having a tendency toward indecisiveness, perfectionism, avoidance, procrastination, and problems with planning and organizing

Excessive acquiring and refusing to discard items results in:

• Disorganized piles or stacks of items, such as newspapers, clothes, paperwork, books or sentimental items
• Possessions that crowd and clutter your walking spaces and living areas and make the space unusable for the intended purpose, such as not being able to cook in the kitchen or use the bathroom to bathe
• Buildup of food or trash to unusually excessive, unsanitary levels
• Significant distress or problems functioning or keeping yourself and others safe in your home
• Conflict with others who try to reduce or remove clutter from your home
• Difficulty organizing items, sometimes losing important items in the clutter

People with hoarding disorder typically save items because:

• They believe these items are unique or will be needed at some point in the future
• The items have important emotional significance — serving as a reminder of happier times or representing beloved people or pets
• They feel safer when surrounded by the things they save
• They don't want to waste anything

Hoarding disorder is different from collecting. People who have collections, such as stamps or model cars, deliberately search out specific items, categorize them and carefully display their collections. Although collections can be large, they aren't usually cluttered and they don't cause the distress and impairments that are part of hoarding disorder.

Hoarding animals

People who hoard animals may collect dozens or even hundreds of pets. Animals may be confined inside or outside. Because of the large numbers, these animals often aren't cared for properly. The health and safety of the person and the animals are at risk because of unsanitary conditions.

It's not clear what causes hoarding disorder. Genetics, brain functioning and stressful life events are being studied as possible causes.

Hoarding usually starts around ages 11 to 15, and it tends to get worse with age. Hoarding is more common in older adults than in younger adults.

Risk factors include:

• Personality. Many people who have hoarding disorder have a temperament that includes indecisiveness.
• Family history. There is a strong association between having a family member who has hoarding disorder and having the disorder yourself.
• Stressful life events. Some people develop hoarding disorder after experiencing a stressful life event that they had difficulty coping with, such as the death of a loved one, divorce, eviction or losing possessions in a fire.

Hoarding disorder can cause a variety of complications, including:

• Increased risk of falls
• Injury or being trapped by shifting or falling items
• Family conflicts
• Loneliness and social isolation
• Unsanitary conditions that pose a risk to health
• A fire hazard
• Poor work performance
• Legal issues, such as eviction

Other mental health disorders

Many people with hoarding disorder also experience other mental health disorders, such as:

• Depression
• Anxiety disorders
• Obsessive-compulsive disorder (OCD)
• Attention-deficit/hyperactivity disorder (ADHD)