How to differentiate between a spiritual experience and a mental disorder or delusion?

Many spiritual teachings ask the followers to develop detachment towards worldly objects and events. Certain meditation techniques ask the followers to be a mere spectator to one's thoughts and get emotionally detached. Few spiritual people report having spiritual experiences like out-of-body or having seen a deity in their dreams or in daylight. My question is, how do a follower of spiritual practice differentiate between a spiritual experience and a mental or neurotic disorder like ' dissociative disorder'?