(not in technical use) any disabling mental disorder requiring treatment.
Origin
1900-05, Americanism
Examples from the web for nervous breakdown
After he got back, he achieved some success as a songwriter, but then had a nervous breakdown.
Looking back at the past few months, it's fair to wonder if the country isn't going through a nervous breakdown.
At one point she suffered a nervous breakdown and had to be hospitalized and sedated.
The next year she failed to report for work on three successive films and was reported to be suffering from a nervous breakdown.
It turns out that she had suffered a nervous breakdown, affecting this case and others.
The accusation, which was never substantiated, caused complainant to have a nervous breakdown.
British Dictionary definitions for nervous breakdown
nervous breakdown
noun
1.
any mental illness not primarily of organic origin in which the patient ceases to function properly, often accompanied by severely impaired concentration, anxiety, insomnia, and lack of self-esteem; used esp of episodes of depression
nervous breakdown in Medicine
nervous breakdownn. A severe or incapacitating emotional disorder, especially when occurring suddenly and marked by depression.