While I do agree that the leaders of this cult and rank and file members have to a degree lost some contact with reality I do not think it causes people to suffer psychosis. While banking all your hope on living for an eternity in service to a jealous deity shouting his praises forever has its own form of insanity, it cannot be responcible IMO for psychosis I'm thinking chemical imbalance or genetic play a major role
http://en.wikipedia.org/wiki/Psychosis
Psychosis (from the Greek ψυχή "psyche", for mind/soul, and -ωσις "-osis", for abnormal condition or derangement) refers to an abnormal condition of the mind, and is a generic psychiatric term for a mental state often described as involving a "loss of contact with reality ". People suffering from psychosis are described as psychotic.
People with psychosis may have one or more of the following: hallucinations , delusions , catatonia , or a thought disorder , as described below. Impairments in social cognition also occur
From a diagnostic standpoint, organic disorders were those held to be caused by physical illness affecting the brain (that is, psychiatric disorders secondary to other conditions), while functional disorders were considered to be disorders of the functioning of the mind in the absence of physical disorders (that is, primary psychological or psychiatric disorders). The materialistic view of the mind–body problem holds that mental disorders arise from physical processes; in this view, the distinction between brain and mind, and therefore between organic and functional disease, is an artificial one. Subtle physical abnormalities have been found in illnesses traditionally considered functional, such as schizophrenia. The DSM-IV-TR avoids the functional/organic distinction, and instead lists traditional psychotic illnesses, psychosis due to general medical conditions, and substance-induced psychosis.
Primary psychiatric causes of psychosis include the following: [16] [17] [18]
Psychotic symptoms may also be seen in [18]
Stress is known to contribute to and trigger psychotic states. A history of psychologically traumatic events, and the recent experience of a stressful event, can both contribute to the development of psychosis. Short-lived psychosis triggered by stress is known as brief reactive psychosis, and patients may spontaneously recover normal functioning within two weeks. [19] In some rare cases, individuals may remain in a state of full-blown psychosis for many years, or perhaps have attenuated psychotic symptoms (such as low intensity hallucinations) present at most times.