Neurasthenia (also known as Neuralgia) was a term first coined by Beard in 1869 to describe a condition with symptoms of fatigue, anxiety and pessimism. It was explained as being a result of exhaustion of the central nervous system's energy reserves which Beard attributed to civilisation. In the late 1800s it became a popular diagnosis and led to rest cures.

Postherpetic neuralgia is a painful, often excruciating condition caused by the damage that the varicella zoster virus causes to the affected nerves during and after an attack of herpes zoster (shingles). It usually manifests itself after the pustules have started to die down. The pain is not controlled by traditional painkillers such as opiates and other analgesics as it is a fundamental (neuropathic) nerve pain.

Neuralgia as related to Postherpetic Neuralgia