Ask most people what causes drug addiction, and they’ll probably say drugs. According to this line of conventional wisdom, the pharmacological properties of substances like heroin, cocaine and crystal meth act as chemical hooks which cause users to become addicted once a certain level of consumption has been reached. While this may be true, it doesn’t tell the whole story, and offers no explanation as to why some people feel the need to repeatedly use drugs in the first place while others don’t.

In other words, as Johann Hari suggests in this enlightening TED Talk, “everything you think you know about addiction is wrong.” For instance, if your granny goes into hospital for a hip replacement, they’ll probably give her several massive doses of morphine – which is basically just refined heroin – yet this doesn’t mean she’ll come out as an addict, or indeed ever feel the need to take opioid drugs again.

But if mere exposure to drugs isn’t sufficient to create swaths of geriatric junkies, where does addiction actually from? To answer this question, Hari points to a pivotal study conducted by Canadian psychologist Bruce Alexander.

Known as the Rat Park Experiment, the study revealed how rats kept in solitary confinement tended to opt for water that was laced with morphine over regular water, to the point where they became physically addicted and died of overdoses. In contrast, rats living in the Rat Park were able to interact with other rats and make use of running wheels, nesting areas and other facilities contributing to a positive life experience. Amazingly, these rats showed a preference for water over morphine.

These findings suggest that drugs are often used to try and fill a void in a person’s (or a rat’s) life, providing a kind of crutch for those who need one. Often this need stems from a lack of social fulfilment or connection, and it is this, rather than chemicals, that drives a person to drugs.

Based on this evidence, Hari suggests that the best way to deal with the problem of drug addiction is to embrace those suffer from the condition rather than excluding or chastising them. After all, “the opposite of addiction is not sobriety. The opposite of addiction is connection.”