Abrupt stoppage of drug intake in drug addicts leads to

Withdrawal syndrome occurs if regular dose of drugs/alcohol is abruptly discontinued. This is characterised by anxiety, shakiness, nausea and sweating, which may be relieved when use is resumed again. In some cases, withdrawal symptoms can be severe and even life threatening and the person may need medical supervision.

Waardenburg and Klinefelter's are genetic disorders.

AIDS is a sexually transmitted infection (STI).