Archimandrite Sophrony (Sakharov). "On Prayer".
When a spiritual father meets people who tell him about their visions, he is concerned first of all with correctly recognizing the source of the vision: whether it was truly given from Above, or it is only a product of an excited fantasy, or a consequence of the influence of hostile spirits. It is sometimes a difficult and extremely demanding challenge. If we attribute what is given by God to an opposing force, then we risk falling into blasphemy against the Holy Spirit (cf.: Matt. 12:28-31). And vice versa: if we recognize demonic action as Divine, then we push the confessing person who trusts us to worship demons. Hence, all spiritual fathers without exception need fervent and constant prayer in general and in each individual case, so that the Lord Himself will protect him from errors in his judgments.
When the state of affairs is unclear to the spiritual father, he has a "psychological technique" at his disposal: to suggest that the confessing person be distrustful of any kind of special phenomena. If the vision was truly from God, then humility will prevail in his, the person's, soul, and he will calmly accept the advice to be sober. Otherwise, a negative reaction is possible, as well as a desire to prove that the vision could not have been otherwise than from God. Then there is some reason to doubt this. Of course, such a method is nothing more than a palliative, and one should not resort to it frivolously. Experience has shown that when someone tempts his brother, he thereby pushes him to irritation and grief.