Substance abuse, memory, and post-traumatic stress disorder

Summary & key facts

This review looks at how three common drugs of abuse—nicotine, cocaine, and alcohol—change learning and memory and how those changes connect with stress and post-traumatic stress disorder (PTSD). The authors describe how these drugs can either help or hurt memory depending on dose, how long they are used, and whether someone is intoxicated or in withdrawal. They also explain how brain areas involved in fear and memory (the amygdala, hippocampus, and prefrontal cortex) are affected in PTSD and by drug use, and how those effects could make PTSD harder to treat.

Key facts:

• The review focuses on three drugs: nicotine, cocaine, and alcohol (ethanol).
• Effects of a drug on memory depend on the drug itself, the pattern of exposure (acute vs. chronic), and the drug state at the time of learning or testing (intoxicated, sober, or in withdrawal).
• Substance use disorders are often comorbid with anxiety disorders such as PTSD; the review cites a high overlap between these conditions.
• Pavlovian fear conditioning is used in the lab to study how stress and drugs change fear learning. In this method, a neutral cue (like a tone) is paired with a painful event until the cue alone causes fear responses (for example, freezing).
• The amygdala is a key brain region for forming fear memories. The hippocampus is important for contextual and trace forms of fear learning. Parts of the prefrontal cortex help inhibit fear and are important for extinction (learning that a c
• Studies cited in the review report that people with PTSD show reduced hippocampal volume on MRI and altered activity: reduced medial prefrontal cortex activity and increased amygdala engagement. The review also notes reduced amygdala volume
• The authors state that abused drugs operate through both shared and distinct brain mechanisms and can alter learning and memory in multiple ways. They say these drug effects may worsen the development, persistence, and treatment of PTSD, bu

Topics

Memory and Neural Mechanisms Neuroscience and Neuropharmacology Research Nicotinic Acetylcholine Receptors Study

Categories

Cognitive Neuroscience Life Sciences Neuroscience

Tags

Anxiety Biology Clinical psychology Cognition Context (archaeology) Drug Extinction (optical mineralogy) Hippocampus Memory consolidation Neuroscience Nicotine Paleontology Psychiatry Psychology Substance abuse Traumatic stress