Glutamate receptors play an important role in regulating the reinforcing effects of misused illicit drugs.Administration of methamphetamine to rodents causes DNA damage in their brain, particularly in the nucleus accumbens region. During repair of such DNA damages, persistent chromatin alterations may occur such as in the methylation of DNA or the acetylation or methylation of histones at the sites of repair. These alterations can be epigenetic scars in the chromatin that contribute to the persistent epigenetic changes found in methamphetamine addiction. Treatment and management
A 2018 systematic review and network meta-analysis of 50 trials involving 12 different psychosocial interventions for amphetamine, methamphetamine, or cocaine addiction found that combination therapy with both contingency management and community reinforcement approach had the highest efficacy (i.e., abstinence rate) and acceptability (i.e., lowest dropout rate). Other treatment modalities examined in the analysis included monotherapy with contingency management or community reinforcement approach, cognitive behavioral therapy, 12-step programs, non-contingent reward-based therapies, psychodynamic therapy, and other combination therapies involving these.As of December 2019, there is no effective pharmacotherapy for methamphetamine addiction. A systematic review and meta-analysis from 2019 assessed the efficacy of 17 different pharmacotherapies used in RCTs for amphetamine and methamphetamine addiction; it found only low-strength evidence that methylphenidate might reduce amphetamine or methamphetamine self-administration. There was low- to moderate-strength evidence of no benefit for most of the other medications used in RCTs, which included antidepressants (bupropion, mirtazapine, sertraline), antipsychotics (aripiprazole), anticonvulsants (topiramate, baclofen, gabapentin), naltrexone, varenicline, citicoline, ondansetron, prometa, riluzole, atomoxetine, dextroamphetamine, and modafinil.
Balanitis is inflammation of the glans penis. When the foreskin is also affected, the proper term is balanoposthitis. Balanitis on boys still in diapers must be distinguished from redness caused by ammoniacal dermatitis. The word balanitis is from the Greek βάλανος balanos, literally meaning acorn, used because of the similarity in shape to the glans penis. Signs and symptoms
Small red erosions on the glans (first sign)
Redness of the foreskin
Redness of the penis
Other rashes on the head of the penis
Foul smelling discharge
Painful foreskin and penis

Complications
Recurrent bouts of balanitis may cause scarring of the preputial orifice; the reduced elasticity may lead to pathologic phimosis. Further complications may include: 

Stricture of urethral meatus
Phimosis
Paraphimosis

Cause
Inflammation has many possible causes, including irritation by environmental substances, physical trauma, and infection such as bacterial, viral, or fungal. Some of these infections are sexually transmitted diseases. It is less common among people who are circumcised, as in many cases, a dysfunction of the foreskin is a causal or contributing factor. Both not enough cleaning and too much cleaning can cause problems. Diabetes can make balanitis more likely, especially if the blood sugar is poorly controlled.It is important to exclude other causes of similar symptoms such as penile cancer. Diagnosis
Diagnosis may include careful identification of the cause with the aid of a good patient history, swabs and cultures, and pathological examination of a biopsy. Types
Zoons balanitis, also known as Balanitis Circumscripta Plasmacellularis or plasma cell balanitis (PCB), is an idiopathic, rare, benign penile dermatosis for which circumcision is often the preferred treatment.