A condition in which parting with objects (e.g., household items or personal possessions) causes significant distress. In addition, many individuals continuously acquire new things and experience distress if they are not able to do so. The inability to discard possessions can make living spaces nearly unusable. Relatedly, the cluttered living space can interfere with the performance of daily tasks, such as personal hygiene, cooking, and sleeping (e.g., the shower is full of stuff, the bed is covered with clutter).

Anxiety disorders reflect disorders that share a general feature of excessive fear (i.e. emotional response to perceived or real threat) and/or anxiety (i.e. anticipation of future threat) and demonstrate behavioral and functional disturbances as a result. Panic attacks are a feature that can occur in the context of many anxiety disorders and reflect a type of fear response.

In order to manage threatening situations, humans have evolved to experience a "fight or flight" response. As part of this response, when humans are confronted with a dangerous situation, their body mobilizes by sending blood away from their extremities (e.g. hands and feet) and into the major muscles, producing adrenaline, and increasing heart rate so that we are better equipped to fight off danger.
A phobia is an unrealistic or exaggerated fear of a specific object, activity, or situation that in reality presents little to no danger. Common phobias include fear of animals (such as snakes and spiders), fear of flying, and fear of heights. In the case of a severe phobia, you might go to extreme lengths to avoid the thing you fear. Unfortunately, avoidance only strengthens the phobia.
When we’re anxious, the body produces a stress response. The stress response is designed to give us an extra ‘boost’ of awareness and energy when we think we could be in danger. The stress response causes a number of physiological, psychological, and emotional changes in the body that enhance the body’s ability to deal with a perceived threat – to either fight or flee, which is the reason the stress response is often referred to as the ‘fight or flight response.’