Salvador Dali never used drugs, especially since he spoke about it himself. He also explained the reason for his "metamorphoses" in sufficient detail, namely by experiments on sleep and wakefulness. As you know, he loved to wake himself up during the so-called deep sleep and record the brightest moments of dreams. Nothing more.
In his youth, he probably experimented and tried drugs! Why not? But are you wondering if he created his paintings under the influence of drugs? Definitely - NO! And I'll explain why not. Anyone who has ever seen Dali's canvases up close could be convinced that his writing technique is so perfect, so sophisticated that it does not allow the slightest uncertainty and weakness. It's an iron hand! This is the hand of a person who knows exactly HOW and WHAT to do. Dali had incredible imagination and amazing ability to make those fantasies come true. His paintings, especially the period of 40-50 years, are striking in technical perfection and mathematical precision. He owns the craft at the level of Michelangelo and Raphael. This is absolutely impossible to achieve in a narcotic half-sleep. Look at the paintings of drug addicts and madmen and compare with the paintings of Dali and you will immediately understand where the iron hand of a genius, and where is the sluggish paw you will.