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What is Substance Use Disorder (SUD) and how is it diagnosed according to DSM-5?

Substance Use Disorder (SUD) is characterized by a harmful pattern of substance use that leads to significant impairment or distress. Diagnosis requires meeting at least two of the 11 criteria outlined in the DSM-5 within a 12-month period.

Substance Use Disorder (SUD) types of criteria

• Impaired control

• Social and functional impairment

• Risky or harmful use

• Physiological dependance

Impaired Control

• Taking more or using for longer than intended

• Unsuccessful attempts to quit

• Significant time spent obtaining, using, or recovering from substance

• Strong cravings or psychological urges or desires to use the substance

Social and Functional Impairment

• Neglecting work, school, or home responsibilities.

• Continued use despite causing conflicts in relationships or interpersonal problems

• Loss of interest in hobbies, social, or occupational activities.

Risky or Harmful Use

• Using the substance in physically dangerous situations (e.g., driving under the influence).

• Continued use despite knowing it worsens physical or mental health issues.

Physiological Dependence

• Tolerance – Needing more of the substance

  for the same effect or experiencing reduced

  effects over time.

• Withdrawal – Experiencing withdrawal

  symptoms or using the substance to avoid

  withdrawal effects.

Gambling Disorder

Characterized by persistent and recurrent problematic gambling behavior leading to significant distress or impairment.

Diagnostic criteria include:

• loss of control,

• tolerance

• withdrawal

• continued gambling despite negative consequences

Internet Gaming Disorder (IGD)

Disorder characterized by:

• compulsive online gaming

• withdrawal symptoms

• neglect of daily activities due to gaming

Compulsive Sexual Behavior Disorder (CSBD)

Also known as 'Sex Addiction.

It is defined as:

• persistent patterns of sexual behavior that cause distress or impairment and are difficult to control.

Internet & Social Media Addiction

Excessive internet/social media use has been researched as an addiction-like behavior. Often associated with impulse control and compulsivity

Shopping Addiction (Compulsive Buying Disorder)

Considered under Impulse Control Disorders.

Compulsive, uncontrollable shopping that leads to financial and emotional distress

Food Addiction

Concept is linked to Binge-Eating Disorder (BED)

Highly processed foods (e.g., sugar, fat, etc.) may have addictive properties

Exercise Addiction

Compulsive exercise is sometimes linked to Eating Disorders (e.g., Anorexia Nervosa)

Relapse

Returning to using drugs or alcohol after a period of abstinence.

Relapse Triggers

• Emotional: Negative emotions

• Environmental: Drug paired cues

• Exposure: The drug itself

Mesolimbic dopamine reward pathway

The brain’s natural reward mechanism which is involved in reinforcing behaviors that are essential for survival, such as eating and reproduction. Drug abuse hijacks this mechanism.

What is the normal function of the dopamine uptake pump in the brain?

The dopamine uptake pump normally terminates the neural effects of dopamine by reabsorbing it back into the neuron. This ensures that there is no excess amount of dopamine.

How does cocaine affect dopamine levels in the synapse?

Cocaine blocks the dopamine uptake pump, which keeps more dopamine in the synapse, prolonging its effects. This results in less dopaminic receptors, yet they can return under specific circumstances.

Memory in relation to drugs

Drug-associated cues make for very strong memories that can be highly resistant to forgetting or loss.

Extinction Learning

A process in which the conditioned response (drug-seeking behavior) is diminished or eliminated after repeated exposure to the conditioned stimulus (drug-related cues) without any reinforcement (drug effects).

Renewal

Relapse when exposed to the drug-associated environment (context or cue-induced relapse)

Reinstatement

Relapse when exposed to the drug itself again (priming-induced relapse)

Spontaneous recovery

Relapse over time (time-dependent relapse)

Methadone

A long-acting opioid agonist that works by binding to the same opioid receptors in the brain as other opioids, such as heroin and fentanyl. Has a risk of dependance and used in severe cases without needing a detox first.

Benefits of Methadone

• Prevents withdrawal symptoms without inducing euphoria

• Suppresses cravings because it binds to opioid receptors for a long time (24-36 hrs)

• Prevents other opioids from having a significant effect (i.e. a high), which discourages misuse

• Helps restore balance, reducing the compulsive drug-seeking behaviors

Naltrexone for opioid addiction

Used for long-term treatment of opioid and alcohol addiction. Does not treat withdrawal or cravings, but it blocks the effects of opioids, preventing relapse. Must detox for 7-10 days before starting; otherwise, it can trigger precipitated withdrawal (sudden, severe withdrawal symptoms).

Benefits of Naltrexone for opioid addiction

• Works best for people who have already detoxed and want to stay opioid-free

• No risk of addiction or misuse

• Unlike methadone, it does not cause physical dependence, but efficacy may not be as good

Naltrexone for alcohol use disorder

• Blocks endorphins (which normally activate opioid receptors) making alcohol less rewarding and removing the ‘buzz’.

• Reduces cravings, alcohol becomes less pleasurable

• Does NOT cause sickness like Antabuse (disulfiram)

Semaglutide (Ozempic)

GLP-1 agonists reduce impulsive behaviors by regulating dopamine (DA) release. Participants experienced a 30% reduction in alcohol consumption and fewer cravings.

Psychedelic-Assisted Therapy

A trial is investigating whether DMT (dimethyltryptamine) can disrupt alcohol-related reward memories, potentially reducing alcohol misuse.

Brain stimulation

Focused ultrasound brain stimulation waves targeting the nucleus accumbens, leads to significant decrease in drug cravings among participants.

Mindfulness-Oriented Recovery Enhancement (MORE)

Like MCBT. Combines mindfulness training with cognitive-behavioral techniques to address addiction. Clinical trials have demonstrated its efficacy in reducing opioid misuse and associated emotional distress.

Reconsolidation

Stable memories become labile every time they are retrieved

Memory updating in relation to drug misuse

• Memory in "Inactive State" – Stored drug-related memories are stable and not easily changed.

• Reactivation – Exposure to drug cues (e.g., places, paraphernalia) triggers recall, making the memory temporarily unstable.

• Memory in “Active State” – The memory can be modified before restabilizing.

• Restabilization (Reconsolidation) – The memory is updated with new information or weakened if drug effects do not follow the cues.

Δ9-tetrahydrocannabinol (THC)

This drug interacts with cannabinoid receptors (CB1, CB2) in the brain, influencing various cognitive functions.

Risks of THC

It can impair memory, attention, and learning, especially in developing brains, and while it is less addictive compared to substances like nicotine or opioids, it can still lead to dependence in some users.

Cannabidiol (CBD)

This is a cannabinoid found in cannabis that is non-psychoactive, meaning it does not bind to CB1 receptors. Instead, it interacts with serotonin and dopamine receptors, which may help explain its impacts on anxiety, pain, and inflammation.

Benefits of CBD

Potential benefits include reduction in seizures, alleviation of anxiety and stress, relief from pain and inflammation, and possibly neuroprotective effects.

Risks of CBD

This is generally well-tolerated, but potential side effects may include fatigue, diarrhea, and interactions with other drugs. Regulatory issues exist as many over-the-counter products are not FDA-regulated, leading to inconsistencies in purity and potency.