Diagnosis with a potentially fatal illness is distressing and can provoke anxiety that further reduces quality of life, and a treatment that reduces anxiety when facing deteriorating health and mortality will improve quality of life for people with such illnesses. Forty to fifty years ago, researchers investigated lysergic acid diethylamide (LSD) in combination with psychotherapy to treat anxiety when facing advanced stage cancer. This psychedelic (hallucinogenic) drug can produce transformative or mystical experiences and insights that can help in anxiety reduction. This study will be a randomized, active placebo controlled,double-blind pilot study of the safety and efficacy of LSD-assisted psychotherapy as a way of reducing anxiety in people with potentially fatal illnesses. This study will examine whether two sessions of LSD-assisted psychotherapy scheduled two to four weeks apart will reduce anxiety and improve quality of life for people experiencing anxiety as a result of a potentially fatal illness.