Paruresis

Paruresis (/ˌpɑːrəˈriːsɪs/ PAR-ə-REE-sis) is a type of phobia in which the sufferer is unable to urinate in the real or imaginary presence of others, such as in a public restroom. The analogous condition that affects bowel movement is called parcopresis.

It appears that paruresis involves a tightening of the sphincter and/or bladder neck due to a sympathetic nervous system response. The adrenaline rush that produces the involuntary nervous system response probably has peripheral and central nervous system involvement. The internal urethral sphincter (smooth muscle tissue) or the external urethral sphincter (striated muscle), levator ani (especially the pubococcygeus) muscle area, or some combination of the above, may be involved. It is possible that there is an inhibition of the detrusor command through a reflex pathway as well. The pontine micturition center (Barrington's nucleus) also may be involved, as its inhibition results in relaxation of the detrusor and prevents the relaxation of the internal sphincter.