Dr. Daniel Amen: Any alcohol cuts brain blood flow on scans

Amen cites the US Surgeon General and American Cancer Society: any alcohol increases risk of at least seven cancers. Brain SPECT scans of drinkers show global decreases in blood flow, a “scalloped,” shrunken appearance, and smaller hippocampi. Even light drinkers in a Spanish study had disrupted white matter—the brain’s ‘highways’—suggesting that there is no completely safe dose for brain integrity. Alcohol also acutely crashes frontal lobe activity, removing behavioral brakes and contributing to bad decisions, relationship damage, and higher dementia risk.

Amen’s study of 1,000 marijuana users found lower activity in every brain region; new JAMA data show reduced hippocampal activity and volume with long-term cannabis use, impairing memory and learning. Teenage marijuana use is linked to higher anxiety, depression, and suicide risk in the 20s. He warns that psilocybin-associated psychosis has risen ~300%, with vulnerable individuals flipping into psychosis, and argues we’re repeating past mistakes (benzos, opioids) by rushing into mass psychopharmacology without adequate brain-based selection or safeguards.

Using his BRIGHT MINDS framework, Amen notes that diabesity (overweight and/or high blood sugar) drives 10 of 11 major dementia risk factors, including inflammation, vascular damage, hormonal disruption, and poor sleep. A Mayo Clinic study showed a fat-based diet (fish, nuts, healthy oils) cut Alzheimer’s risk by 42%, protein-based by 21%, while simple-carb-heavy diets (bread, pasta, potatoes, rice, juice, sugar) increased Alzheimer’s risk by 400%. Elevated blood sugar makes vessels brittle, increases stroke risk, and accelerates brain shrinkage, justifying “type 3 diabetes” as a label for Alzheimer’s.

In the US, 85% of psychiatric medications are prescribed in seven-minute visits by non-psychiatrists, often as ‘fast answers’ without proper assessment. Amen emphasizes that SSRIs suppress symptoms but do not heal underlying causes and induce dependence. Randomized trials show saffron, regular brisk walking (45 minutes, 4x/week), omega-3 supplementation, and cognitive training to challenge negative thoughts are each as effective as antidepressants for mild-to-moderate depression, with better side-effect profiles—especially saffron, which can enhance rather than suppress sexual function.

Amen’s recent study shows chronic negativity decreases prefrontal activity, undermining motivation, focus, and mood. He trains patients to identify and challenge “automatic negative thoughts” using structured questions (Is it true? How do I feel with/without this thought? What’s the opposite and is it truer?) and to deliberately cultivate a positivity bias by starting the day with “Today is going to be a great day” and ending with “What went well today?” Over time this shifts attention toward solutions and strengthens frontal regulation over the emotional brain.