Background: It is commonly believed that birth order is an important determinant of personality, intelligence, and economic success. A number of recently published popular books, each with its own approach to the topic tend to support the belief. In keeping with published studies, we noted strong evidence of race and ethnicity effects. In addition, we find that adolescents who lived with both of their parents are much less likely to have used tobacco, alcohol, or marijuana, whereas household income seems to have an effect on female, but not male, substance use. Growing up in an urban area is associated with an increase in the probability of having smoked marijuana and, for females only, an increase in the probability of having drunk alcohol. We find that children with older siblings are, on average, more likely to have used tobacco, alcohol, and canabis than their firstborn counterparts controlling for family size, age, and the other factors in the model. Males with older siblings are 6.2 percentage points more likely to have drunk alcohol and are 5.1 percentage points more likely to have tried marijuana than their firstborn counterparts. With this intention we observed the influence of birth order of the individual among the siblings on the course and outcome of the drug abused subject in the eastern part of India that is known at West Bengal, and its inhabitant called Bengalis. Materials and methods: The data were collected on the basis of retrospective study of the records of 225 consecutive Bengali heroin and brown sugar dependents attending at Ashadeep De-Addiction Centre in Kolkata. All the subjects were male, the age spanned 15-35 years; and hailed from low or middle socio-economic status. All the subjects were treated for detoxification and were followed up while they were undergoing the counselling sessions. The subjects were followed up for little over one year. Results: In Bengali culture the eldest, youngest and the only son, are usually considered to be of much valued position. No such extraordinarily value is attached to any other intermediate ranks. In Bengali, the eldest one usually learns to sacrifice, to tolerate and to be loyal to the hierarchical value-system, whereas the youngest one usually enjoys the indulgence, given not only by parents but also the other elder siblings, and often exhibit poor frustration tolerance and strong pleasure-seeking attitude. The first-born in having a better prognosis, and less drop-out than the lastborns, are expected to be more amenable to therapy than the latter. Conclusion: We are fully aware that the cultural influence is much more varied, extensive, intricate and complex. In such broader perspective, the present study is only a modest attempt. However, we hope that this will throw some light on such a vast subject.