Is it common to feel mentally cluttered all the time?

Yes, many adults with ADHD describe a constant sense of mental fullness or crowding. Thoughts overlap, tasks compete for attention, and nothing feels fully quiet. This can happen even during rest. Clinicians understand this as difficulty filtering and prioritizing mental input rather than anxiety alone. External organization, writing things down, and reducing internal tracking can help create mental space. The clutter is not imagined. It reflects how information is processed.