According to Chapter 1, the principal social psychological factor in determining the presence of an individual's drug abuse is:

Motivation

Explanation:

Motivation and motivational construct both are the most important factor in drug abuse. In many investigations, it's been found, substance abuse has been approached in term of its fulfilling different goals and excitement of life. The most common explanation for taking drugs is two-sided hedonistic hypothesis.

The drug addiction used to achieve high pleasant feelings. To escape withdrawal symptoms or cope up with negative symptoms. Used for fulfilling heterogeneous motives such as socializing and fitted themselves in society. Positive expectencies increasing the use of drugs Used for maximizing the desired outcomes