Neuroimaging has shown functional and structural alterations in the brain. A 2017 study showed that chronic intake of opioids, such as heroin, may cause long-term effects in the orbitofrontal area (OFC), which is essential for regulating reward-related behaviors, emotional responses, and anxiety. Moreover, neuroimaging and neuropsychological studies demonstrated dysregulation of circuits associated with emotion, stress and high impulsivity. Dependence
Drug dependence is an adaptive state associated with a withdrawal syndrome upon cessation of repeated exposure to a stimulus (e.g., drug intake). Dependence is a component of a substance use disorder. Opioid dependence can manifest as physical dependence, psychological dependence, or both.Increased brain-derived neurotrophic factor (BDNF) signaling in the ventral tegmental area (VTA) has been shown to mediate opioid-induced withdrawal symptoms via downregulation of insulin receptor substrate 2 (IRS2), protein kinase B (AKT), and mechanistic target of rapamycin complex 2 (mTORC2). As a result of downregulated signaling through these proteins, opiates cause VTA neuronal hyperexcitability and shrinkage (specifically, the size of the neuronal soma is reduced). It has been shown that when an opiate-naive person begins using opiates in concentrations that induce euphoria, BDNF signaling increases in the VTA.Upregulation of the cyclic adenosine monophosphate (cAMP) signal transduction pathway by cAMP response element binding protein (CREB), a gene transcription factor, in the nucleus accumbens is a common mechanism of psychological dependence among several classes of drugs of abuse. Upregulation of the same pathway in the locus coeruleus is also a mechanism responsible for certain aspects of opioid-induced physical dependence.
Erosive pustular dermatitis of the scalp  presents with pustules, erosions, and crusts on the scalp of primarily older Caucasian females, and on biopsy, has a lymphoplasmacytic infiltrate with or without foreign body giant cells and pilosebaceous atrophy. : 650 : 761

See also
Skin lesion
Cicatricial alopecia
List of cutaneous conditions


== References ==