I can give you some general insights into how psychiatrists might approach the evaluation of belief systems like the Heaven's Gate cult.
Psychiatrists and mental health professionals follow established diagnostic criteria, such as those found in the Diagnostic and Statistical Manual of Mental Disorders (DSM-5), to diagnose mental illnesses. Delusional disorder is one such condition characterized by persistent false beliefs that are not based in reality and are not culturally or socially accepted. These delusions can be bizarre or non-bizarre.
In the case of the Heaven's Gate cult, the members held beliefs that could be considered delusional in nature, as they thought they would be taken to a higher existence by aliens after committing suicide. The combination of shared false beliefs, intense group dynamics, and an overall departure from the consensus reality could be subject to psychiatric evaluation.
However, it's essential to recognize that diagnosing someone as delusional is a complex process. Mental health professionals take into account various factors, including the individual's specific beliefs, cultural context, the impact of the beliefs on their functioning, and whether the beliefs are consistent with a broader cultural or religious system.
When evaluating a belief system like Heaven's Gate, psychiatrists would approach it from a clinical and objective standpoint, focusing on the individual's mental state and its impact on their life and the lives of others. Nevertheless, it's crucial to remember that posthumous psychiatric diagnoses are generally discouraged due to the ethical complexities involved, and it is essential to respect the privacy and dignity of those involved, particularly when they are no longer alive to participate in the evaluation.