Douglas Harper's Etymology Dictionary
1927; see dis- + inhibition. From the start it was noted as being, often, "inhibition of an inhibition."
Wiktionary
n. A lack or loss of inhibition.
Wikipedia
In psychology, disinhibition is a lack of restraint manifested in disregard for social conventions, impulsivity, and poor risk assessment. Disinhibition affects motor, instinctual, emotional, cognitive, and perceptual aspects with signs and symptoms similar to the diagnostic criteria for mania. Hypersexuality, hyperphagia, and aggressive outbursts are indicative of disinhibited instinctual drives.
Usage examples of "disinhibition".
What if the doctor was right - that mixing illusory drugs and alcoholic disinhibition was really more than the human brain could handle?
It is a matter of complex control and feedback mechanisms, inhibition and disinhibition of signal transmission.
It was followed by an increase in activity, with the whole brain growing brighter and brighter as disinhibition caused neurons to fire again immediately after they'd last fired.