{"id":43365,"date":"2012-09-10T00:00:00","date_gmt":"2012-09-10T00:00:00","guid":{"rendered":"https:\/\/www.christianitytoday.com\/pastors\/preaching\/sermon-illustrations\/study-shows-harm-from-long-term-marijuana-use\/"},"modified":"2012-09-10T00:00:00","modified_gmt":"2012-09-10T00:00:00","slug":"study-shows-harm-from-long-term-marijuana-use","status":"publish","type":"sermon-illustrations","link":"https:\/\/www.christianitytoday.com\/pastors\/preaching\/sermon-illustrations\/study-shows-harm-from-long-term-marijuana-use\/","title":{"rendered":"Study Shows the Harm from Long-Term Marijuana Use"},"content":{"rendered":"<p>A new study from New Zealand concluded that &quot;young people who smoke [marijuana] for years run the risk of a significant and irreversible reduction in their IQ.&quot; An international team of researchers studied around 1,000 people who regularly used marijuana. The team assessed the drug users as children before they had started using pot, and then re-interviewed them over a 20 year period after the study participants had started smoking pot.<\/p>\n\n<p>An article from the BBC summarized the results of the study:<\/p>\n\n<blockquote class=\"wp-block-quote is-layout-flow wp-block-quote-is-layout-flow\">\n<p>They found that those who persistently used cannabis&mdash;smoking it at least four times a week year after year through their teens, 20s and, in some cases, their 30s&mdash;suffered a decline in their IQ. The more that people smoked, the greater the loss in IQ. The effect was most marked in those who started smoking cannabis as adolescents.<\/p>\n\n<\/blockquote>\n\n<p>A researcher not associated with the study concluded, &quot;It is of course part of folk-lore among young people that some heavy users of cannabis &hellip; seem to gradually lose their abilities and end up achieving much less than one would have anticipated. This study provides one explanation as to why this might be the case.&quot;<\/p>","protected":false},"author":30,"featured_media":0,"template":"","tax_ctp_audience":[],"tax_ctp_authors":[],"tax_ctp_categories":[165],"tax_ctp_format":[171],"tax_ctp_illustration_types":[410],"tax_ctp_multimedia":[],"tax_ctp_point_editor":[],"tax_publications":[140],"tax_ctp_tags":[3380,3383,3677,3726,3740,3770,3806,3830,4423,4915,4982,5130],"tax_ctp_topics":[388],"class_list":["post-43365","sermon-illustrations","type-sermon-illustrations","status-publish","hentry","tax_publications-ct-pastors","tax_ctp_tags-addiction","tax_ctp_tags-adolescence","tax_ctp_tags-consequences-of-sin","tax_ctp_tags-culture","tax_ctp_tags-debauchery","tax_ctp_tags-destructive-sin","tax_ctp_tags-dissipation","tax_ctp_tags-drugs","tax_ctp_tags-marijuana","tax_ctp_tags-self-destruction","tax_ctp_tags-sinful-pleasure","tax_ctp_tags-teens"],"acf":{"scripture_references":[{"first_verse":null,"add_second_verse":false,"second_verse":null},{"first_verse":null,"add_second_verse":false,"second_verse":null},{"first_verse":null,"add_second_verse":false,"second_verse":null},{"first_verse":null,"add_second_verse":false,"second_verse":null},{"first_verse":null,"add_second_verse":false,"second_verse":null},{"first_verse":null,"add_second_verse":false,"second_verse":null},{"first_verse":null,"add_second_verse":false,"second_verse":null},{"first_verse":null,"add_second_verse":false,"second_verse":null},{"first_verse":null,"add_second_verse":false,"second_verse":null},{"first_verse":null,"add_second_verse":false,"second_verse":null},{"first_verse":null,"add_second_verse":false,"second_verse":null}]},"yoast_head":"<!-- This site is optimized with the Yoast SEO plugin v22.9 - https:\/\/yoast.com\/wordpress\/plugins\/seo\/ -->\n<title>Study Shows the Harm from Long-Term Marijuana Use - CT Pastors<\/title>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/www.christianitytoday.com\/pastors\/preaching\/sermon-illustrations\/study-shows-harm-from-long-term-marijuana-use\/\" \/>\n<meta property=\"og:locale\" content=\"en_US\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"Study Shows the Harm from Long-Term Marijuana Use - CT Pastors\" \/>\n<meta property=\"og:description\" content=\"A new study from New Zealand concluded that &quot;young people who smoke [marijuana] for years run the risk of a significant and irreversible reduction in their IQ.&quot; An international team of researchers studied around 1,000 people who regularly used marijuana. The team assessed the drug users as children before they had started using pot, and Read more...\" \/>\n<meta property=\"og:url\" content=\"https:\/\/www.christianitytoday.com\/pastors\/preaching\/sermon-illustrations\/study-shows-harm-from-long-term-marijuana-use\/\" \/>\n<meta property=\"og:site_name\" content=\"CT Pastors\" \/>\n<meta property=\"article:publisher\" content=\"https:\/\/www.facebook.com\/CTPastors\" \/>\n<meta property=\"og:image\" content=\"https:\/\/www.christianitytoday.com\/pastors\/wp-content\/uploads\/sites\/19\/2025\/12\/ogimage.png?resize=1200,628\" \/>\n\t<meta property=\"og:image:width\" content=\"1200\" \/>\n\t<meta property=\"og:image:height\" content=\"628\" \/>\n\t<meta property=\"og:image:type\" content=\"image\/png\" \/>\n<meta name=\"twitter:card\" content=\"summary_large_image\" \/>\n<meta name=\"twitter:site\" content=\"@CTpastors\" \/>\n<script type=\"application\/ld+json\" class=\"yoast-schema-graph\">{\"@context\":\"https:\/\/schema.org\",\"@graph\":[{\"@type\":\"WebPage\",\"@id\":\"https:\/\/www.christianitytoday.com\/pastors\/preaching\/sermon-illustrations\/study-shows-harm-from-long-term-marijuana-use\/\",\"url\":\"https:\/\/www.christianitytoday.com\/pastors\/preaching\/sermon-illustrations\/study-shows-harm-from-long-term-marijuana-use\/\",\"name\":\"Study Shows the Harm from Long-Term Marijuana Use - CT Pastors\",\"isPartOf\":{\"@id\":\"https:\/\/www.christianitytoday.com\/pastors\/#website\"},\"datePublished\":\"2012-09-10T00:00:00+00:00\",\"dateModified\":\"2012-09-10T00:00:00+00:00\",\"breadcrumb\":{\"@id\":\"https:\/\/www.christianitytoday.com\/pastors\/preaching\/sermon-illustrations\/study-shows-harm-from-long-term-marijuana-use\/#breadcrumb\"},\"inLanguage\":\"en-US\",\"potentialAction\":[{\"@type\":\"ReadAction\",\"target\":[\"https:\/\/www.christianitytoday.com\/pastors\/preaching\/sermon-illustrations\/study-shows-harm-from-long-term-marijuana-use\/\"]}]},{\"@type\":\"BreadcrumbList\",\"@id\":\"https:\/\/www.christianitytoday.com\/pastors\/preaching\/sermon-illustrations\/study-shows-harm-from-long-term-marijuana-use\/#breadcrumb\",\"itemListElement\":[{\"@type\":\"ListItem\",\"position\":1,\"name\":\"Home\",\"item\":\"https:\/\/www.christianitytoday.com\/pastors\/\"},{\"@type\":\"ListItem\",\"position\":2,\"name\":\"Study Shows the Harm from Long-Term Marijuana Use\"}]},{\"@type\":\"WebSite\",\"@id\":\"https:\/\/www.christianitytoday.com\/pastors\/#website\",\"url\":\"https:\/\/www.christianitytoday.com\/pastors\/\",\"name\":\"CT Pastors\",\"description\":\"Timeless wisdom for pastors with forward-thinking solutions\",\"publisher\":{\"@id\":\"https:\/\/www.christianitytoday.com\/pastors\/#organization\"},\"potentialAction\":[{\"@type\":\"SearchAction\",\"target\":{\"@type\":\"EntryPoint\",\"urlTemplate\":\"https:\/\/www.christianitytoday.com\/pastors\/?s={search_term_string}\"},\"query-input\":\"required name=search_term_string\"}],\"inLanguage\":\"en-US\"},{\"@type\":\"Organization\",\"@id\":\"https:\/\/www.christianitytoday.com\/pastors\/#organization\",\"name\":\"Christianity Today\",\"url\":\"https:\/\/www.christianitytoday.com\/pastors\/\",\"logo\":{\"@type\":\"ImageObject\",\"inLanguage\":\"en-US\",\"@id\":\"https:\/\/www.christianitytoday.com\/pastors\/#\/schema\/logo\/image\/\",\"url\":\"https:\/\/www.christianitytoday.com\/pastors\/wp-content\/uploads\/sites\/19\/2025\/08\/logo_ctpastors_black.svg\",\"contentUrl\":\"https:\/\/www.christianitytoday.com\/pastors\/wp-content\/uploads\/sites\/19\/2025\/08\/logo_ctpastors_black.svg\",\"caption\":\"Christianity Today\"},\"image\":{\"@id\":\"https:\/\/www.christianitytoday.com\/pastors\/#\/schema\/logo\/image\/\"},\"sameAs\":[\"https:\/\/www.facebook.com\/CTPastors\",\"https:\/\/x.com\/CTpastors\"]}]}<\/script>\n<!-- \/ Yoast SEO plugin. -->","yoast_head_json":{"title":"Study Shows the Harm from Long-Term Marijuana Use - CT Pastors","robots":{"index":"index","follow":"follow","max-snippet":"max-snippet:-1","max-image-preview":"max-image-preview:large","max-video-preview":"max-video-preview:-1"},"canonical":"https:\/\/www.christianitytoday.com\/pastors\/preaching\/sermon-illustrations\/study-shows-harm-from-long-term-marijuana-use\/","og_locale":"en_US","og_type":"article","og_title":"Study Shows the Harm from Long-Term Marijuana Use - CT Pastors","og_description":"A new study from New Zealand concluded that &quot;young people who smoke [marijuana] for years run the risk of a significant and irreversible reduction in their IQ.&quot; An international team of researchers studied around 1,000 people who regularly used marijuana. 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