According to the Mayo Clinic and Women's Health Magazine, signs of a nervous breakdown may differ depending on the person, but they generally include a number of unusual or dysfunctional behaviors including anxiety, short-tempered behavior, lowered sex drive, difficulty focusing, and missing work and appointments for more than several days. They also include shunning social situations and changes in hygiene, eating and sleeping.
The Mayo Clinic notes that "nervous breakdown" is not a medical term, but it does point to a problem that needs attention. In many cases, the problem may be related to mental health, such as anxiety or depression. A person who is about to have a nervous breakdown is no longer functioning as usual.
As for anxiety, Women's Health Magazine explains that the anxiety does not seem to come from a specific place. Rather, it takes the form of a sense of foreboding. It can happen even if many things in a person's life, such as jobs and relationships, are going well. Stressors may have been deeply buried, and they need to be addressed to avert a nervous breakdown. People who think they may be experiencing a nervous breakdown should talk to their primary care doctors, according to the Mayo Clinic.