<unk>  can be experienced in focal, discrete areas, or as a more diffuse, body-wide form. Conditioning studies have established that it is possible to experience a learned<unk>  of the latter, diffuse form. The focal form is typically associated with injury, and is divided into two subtypes: * Primary<unk>  describes pain sensitivity that occurs directly in the damaged tissues. * Secondary<unk>  describes pain sensitivity that occurs in surrounding undamaged tissues. Opioid-induced<unk>  may develop as a result of long-term opioid use in the treatment of chronic pain. Various studies of humans and animals have demonstrated that primary or secondary<unk>  can develop in response to both chronic and acute exposure to opioids. This side effect can be severe enough to warrant discontinuation of opioid treatment.
Hyperalgesia
Hypoalgesia
Spasticity
Synesthesia
Hypoesthesia
Decompensation
Dysesthesia
Neophobia