Sleep talking may be brought on by stress, depression, fever, sleep deprivation, day-time drowsiness, alcohol, and fever. In many instances sleep talking runs in families, although external factors seem to stimulate the behavior. Sleep talking often occurs concurently with other sleep disorders such as nightmares, confusional arousals, sleep apnea, and REM sleep behavior disorder. In rare cases, adult-onset frequent sleep-talking is associated with a psychiatric disorder or nocturnal seizures. Sleep talking associated with mental or medical illness occurs more commonly in persons over 25 years of age.