I'm a bit confused by the linked article. The only link to a study I found was to [1] published Advances in Psychiatric Treatment. The other study quoted is for

I'm a bit confused by the linked article. The only link to a study I found was to [1] published Advances in Psychiatric Treatment. The other study quoted is for some specific effects the article mentions. Any idea where the link between CYP1A2 and caffein comes from? [1] https://www.cambridge.org/core/journals/advances-in-psychiatric-treatment/article/neuropsychiatric-effects-of-caffeine/7C884B2106D772F02DA114C1B75D4EBF https://www.cambridge.org/core/journals/advances-in-psychiat...