of memory and experience playing in dreaming, unconscious effects such as health of relationships factor into the types of dreams the brain produces. Of the people analyzed, those suffering from "insecure attachments" were found to dream with more frequency and more vividly than those who were evaluated to have "secure attachments". Drugs affecting dreaming Correlations between the usage of drugs and dreaming have been documented, particularly the use of drugs, such as sedatives, and the suppression of dreaming because of drugging effects on the cycles and stages of sleep while not allowing the user to reach REM. Drugs used for their stimulating properties (cocaine, methamphetamine, and ecstasy) have been shown to also decrease the restorative properties of REM sleep and its duration. Dreaming disorders Dreaming disorders are difficult to quantify due to the ambiguous nature of dreaming. However, dreaming disorders can be linked to psychological disorders such as post-traumatic stress disorder expressed as nightmares. Research into dreaming also suggests similarity and links in illusory dreaming and delusions. Post-traumatic stress disorder Diagnostic symptoms include re-experiencing original trauma(s), by means of flashbacks or nightmares; avoidance of stimuli associated with the trauma; and increased arousal, such as difficulty falling or staying asleep, anger, and hypervigilance. Links to post-traumatic stress disorder (PTSD) and dreaming have been made in studying the flashbacks or nightmares the victims would suffer. Measurement of the brain waves exhibited by the subjects experiencing these episodes showed great similarity between those of dreaming. The drugs used to treat those suffering from these symptoms of flashbacks and nightmares would suppress not only these traumatic episodes but also any other sort of dreaming function. Schizophrenia The symptoms of schizophrenia involve abnormalities in the perception or expression of reality primarily focused on delusions and hallucinations. The delusions experienced by those with schizophrenia have been likened to the experience of illusory dreams that have come to be interpreted by the subject as actual experiences. Additional research into medication to suppress symptoms of schizophrenia have also shown to influence the REM cycle of those taking the medication and as a result influence the patterns of sleep and dreaming in the subjects. See also Oneironautics The Lathe of Heaven References Further reading Aserinsky, E. and N. Kleitman. 1953. "Regularly Occurring Periods of Eye Motility and Concomitant Phenomena during Sleep." Science 118: 273-274. Dement, W.C. and N. Kleitman. 1957. "The Relation of Eye Movements during Sleep to Dream