Covert sensitisation is a behavioural therapy used in the reduction of addictive behaviour. Covert sensitisation is based on the principles of classical conditioning and involves a person creating an imagined unpleasant association between the addictive behaviour (e.g. smoking, gambling) and an unpleasant stimulus (e.g. the pain created by an electric shock). For example, if someone was using covert sensitisation to treat pathological gambling, they would imagine themselves gambling (e.g. playing slot machines or cards for money) and then as vividly as they can, imagine a very unpleasant consequence, such as an intense electric shock. By consistently making this association in their mind, they should lose the desire to gamble.