New scientific findings indicate that the act of smoking, whether it involves tobacco, cannabis, or a combination of both, is physically linked to a reduction in the volume of several key brain areas.

This analysis, published in the journal Addiction, systematically reviewed existing research to establish associations between cannabis use, tobacco use, co-use, and overall brain volume measurements.

Key Brain Structures Affected by Smoking

The study highlighted specific regions that show measurable volume decreases in smokers. These areas are vital for complex cognitive and emotional functions.

The Amygdala and Emotional Regulation

The amygdala is crucial for processing emotions, managing fear, and governing survival instincts. It also plays a role in memory and learning.

A reduced amygdala volume can impair a person's ability to regulate feelings effectively. This may manifest as severe anxiety, emotional detachment, or an inability to recognize fear, potentially leading to riskier behaviors.

The Striatum and Movement Control

The striatum, located deep within the brain, is essential for executing smooth, voluntary movements. It is also involved in processing emotions related to motivation, reward, and risk assessment.

Gray Matter Volume and Cognitive Function

Regular cigarette smoking was specifically associated with a decrease in total gray matter volume. Gray matter is the brain tissue responsible for processing sensory input, controlling muscles, and making decisions.

The Hippocampus and Memory Impairment

The hippocampus is fundamental for learning, spatial awareness, and forming both short-term and long-term memories. It is also necessary for recalling specific facts or past experiences.

A reduction in hippocampal volume is recognized as a significant indicator of cognitive impairment and the onset of dementia.

Interconnected Functions and Potential Causes

Many of these affected structures, such as the amygdala and the hippocampus, collaborate closely to ensure full cognitive function, particularly in linking memories to emotional responses.

Researchers suggest that the harmful effects observed from tobacco use may stem from the thousands of carcinogens it contains, potentially causing brain damage through inflammation and oxidative stress.

Conversely, the study noted that CBD, a component found in cannabis, possesses recognized anti-inflammatory and antioxidative properties. This difference might explain why cannabis use did not show as pronounced an effect on brain volume as tobacco use.