Inclusion Criteria:

• Have a diagnosis of advanced-stage potentially fatal illness. As well as metastatic cancer this may include autoimmune, neurological, infectious or rheumatoid diseases as well. The participant must have a probability of survival of more than six months. The estimated life expectancy in relation to the study must be documented.
• The participant makes the decision to participate in the study by his or her own will and that there is no inhibition to his or her will or ability of deciding due to the primary disease.
• Meet DSM-IV criteria for Anxiety Disorder as indicated by the SCID or have a score of at least 40 on each part of the STAI.
• Have failed to respond adequately or at all to medication or psychotherapy intended to reduce anxiety, or have refused to take anxiolytic medication.
• May be diagnosed with another affective disorder other than anxiety disorder, except bipolar-I disorder.
• Are at least 18 years of age.
• Are willing to commit to medication dosing, experimental sessions, follow-up sessions, and to complete evaluation instruments (although they may withdraw from the study at any time without cause).
• Are willing to withdraw from taking any psychiatric medications during the experimental session period. If they are being treated with medications at the time they are first evaluated, they should independently review their use of these medications with their treatment providers. Such drugs must be discontinued long enough before the first LSD treatment session to avoid the possibility of a drug-drug interaction (the interval will be at least 5 times the particular drug's half-life).
• If in ongoing psychotherapy, those recruited into the study may continue to see their outside therapist, provided they sign a release for the investigators to communicate directly with their therapist. Participants should not change therapists, increase or decrease the frequency of therapy or commence any new type of therapy until after the evaluation session 2 months after the second LSD treatment session.
• Participants must agree that, for one week preceding each LSD treatment session:
• a. Clinical judgment will be used to determine permissible herbal supplements.
• b. They will not initiate any new prescription medications (except with prior approval of the research team).
• c. Clinical judgment will be used to determine permissible nonprescription medications.
• Participants must be willing to follow restrictions and guidelines concerning consumption of food, beverages and nicotine the night before and just prior to ech LSD session. Non-routine PRN medications for treating breakthrough pain taken in the 24 hours preceding the LSD treatment session may result in rescheduling the treatment session to another date, with the decision at the discretion of the investigators after discussion with the participant.

Exclusion Criteria:

• Women who are pregnant or nursing, or of child bearing potential and are not practicing an effective means of birth control.
• Anyone with past or present diagnosis with a primary psychotic disorder.
• Meeting DSM-IV criteria for Dissociative Disorder or Bipolar-I Affective Disorder.
• Meeting DSM-IV criteria for abuse of or dependence on any substance (other than caffeine or nicotine) in the past 60 days.
• Diagnosed with significant somatic problems, that in the clinical judgment of the investigators poses too great a potential for side effects.
• No sufficient liver function at the baseline examination or the day before the experimental sessions.
• Having evidence of CNS affection from the primary disease (e.g. brain metastasis), shown by neurocognitive impairment.
• Weighing less than 45 kg.
• Reasonably judged to present a serious suicide risk or who are likely to require psychiatric hospitalization during the course of the study.
• Unable to fully understand the potential risks and benefits of the study and give informed consent.
• Requiring ongoing concomitant therapy with a psychotropic drug (other than as needed, anxiety medications, and pain control medications) and are unable or unwilling to comply with the washout period.