Drugs and their effects When predicting the effects of a drug we need to consider the combined influence of the drug, the person and the place where they are using it. For example, if we consider alcohol, it will have a certain effect when consumed as a toast to celebrate a friend's wedding. It may well have a totally different effect when consumed alone, after an argument with friend. Factors that influence the effects of drugs are: The individual has the user developed a tolerance for the drug their physical health status, eg. liver their age and sex their cultural background psychological factors such as expectations, mental states, social status, motives, personality, current mood and past experiences The substance the amount, strength and purity of the drug any other drugs taken at the same time