This goes the way learning a bicycle went. You could not, then you could but only with all of your attention, then one day you rode without thinking about it. The middle bit is the ugly bit.

What the research says

A clinic study of nearly two hundred anxious young people found that dropping out of treatment was common and predictable from identifiable factors, a reminder that most stopping happens before a skill has settled. It was observational, in one community clinic, so it describes a pattern rather than explaining it. If you are thinking of quitting, it is worth knowing this is the usual point at which people do.

Strength of evidence: one line of research. A single study, or a theoretical account.