Drug addiction can be seen from a number of ways in the chart. First of all, the 2nd house represents what is ingested, particularly through the mouth, since the 2nd house (and the 2nd sign of Taurus) represent the mouth region - food, speech etc. Therefore, malefic planets located in or aspecting the 2nd house or the 2nd lord show a tendency towards foul or addictive oral substances like alcohol and smoking. The nodes of the Moon, Rahu and Ketu, are especially considered planets of addiction, but Saturn and Mars also can represent causing harm to one's self. Also, Venus is a planet of pleasure and indulgence and Jupiter's aspects to Venus can represent overindulgence.
Additionally, the 12th house and the 12th sign of Pisces represent self-destructive tendencies, and escapist patterns. They are the most 'loose' in boundaries being mutable water and represents the dissolution of one's self, and identity. The 12th house, being a moksha house, along with the 4th and 8th houses, represent altered states of awareness. The 8th and 12th houses are also dusthana or malefic houses, along with the 6th house, which can represent illicit or illegal behaviors.
in Whitney Houston's chart, Jupiter in its own sign in the 2nd house conjunct the Moon. This forms a strong gajakesari yoga in the 2nd house, which represents her tremendous singing voice and the wealth she's amassed. These might appear to be benefic influences on the 2nd house and 2nd lord that should protect her against drug addiction. However, notice how both Mars and Saturn also aspect the 2nd house, and the 2nd lord, Jupiter. Saturn particularly aspects Jupiter very closely from the 12th house. Additionally, the 2nd house is the sign of Pisces, an addictive sign under these malefic influences. Jupiter also aspects Venus in the 6th house, which shows her tendency toward indulgence.
It was in her Venus mahadasha, from 1978-1998 that she began taking drugs. It's speculated that this began after her marriage with Bobby Brown in 1992, which was her Venus-Saturn dasha. Since her 10-year Moon mahadasha, which began on July 31st, 2004, her drug problem has become common knowledge in the media. It became out of hand after Feb 2005 when Rahu transited into her 2nd house over her dasha lord Moon, and Jupiter, the 2nd lord. Fortunately, Rahu is now at early degrees in her 2nd house and quite far from the Moon and Jupiter. Saturn's transit through Cancer, while it is conjunct the Sun, and opposite Saturn, her lagna lord, is a crucial time for her recovery. Earlier this year, she was admitted to a rehabilitation program in Arizona.
Whitney Houston's Natal Chart