Feature Article for BANT November 2011 Newsletter
Definitions, Terminology and Prevalence
The NHS Information Centre’s annual survey of drug misuse in England concluded that 2.8m adults were using illegal substances in 2009/10. The most widely used drug was cannabis, followed by cocaine.
The number of people taking illegal drugs has been falling for several years, however, hospital admission due to a drug-related mental health disorder is significantly on the increase. Younger users in particular are using a wider range of recreational drugs and novel compounds.
The terminology of addiction can be confusing. Most substance users do not necessarily become substance abusers (i.e. dependent on drugs and/or alcohol), and the following distinctions should be made:
- ”Use” refers to the taking of substances
- “Abuse” indicates harmful use
- “Dependence” means “substance dependence” as defined by The Diagnostic and Statistical Manual of Mental Disorders (DSM-IV-TR) (2000) , or “addiction” as defined by the International Classification of Diseases (ICD 10).
Substances of abuse (also known as drugs of abuse) are generally classified into different categories, including narcotics (opiates, cannabinoids), depressants (ethanol), stimulants (nicotine, amphetamines, cocaine), hallucinogens (LSD, ecstasy), inhalants (toluene, nitrous oxide). Some substances span more than one category, such as the animal tranquiliser ketamine which is a dissociative anaesthetic (drug class: hallucinogen) with depressant properties. They all have diverse pharmacological properties and produce different effects, yet they all display a common ability to elicit feelings of pleasure and/or relieve negative emotional states.
The use of alcohol and tobacco is much higher than the use of drugs. The Office for National Statistics reported in 2009 that around a fifth of adults in the UK were smokers. There has been a slight fall in alcohol consumption, but an increase in alcohol-related hospital admissions in the UK. In 2009/10, there were more than twice as many alcohol-related admissions to hospital as in 2002/03. Alcohol-related deaths in the UK have more than doubled since the early 1990s , and both alcohol and substance misuse in the workplace remains a significant cause of accidents, lowered productivity and absenteeism.
Addiction is defined as a chronic, relapsing brain disease characterized by compulsive drug use despite profoundly negative health and social consequences. It is considered a brain disease because drugs change the brain’s structure and function, which can have long lasting effects and propel people towards compulsive drug abuse. The neurobiological changes that accompany addiction are still not well understood. Overall risk of addiction (i.e. factors that contribute to the transition from occasional drug use to addiction) is associated with many variables, including history of drug use and route of administration, gender, ethnicity, developmental stage, stress and psychosocial environment. Genetic factors are likely to affect the individual’s vulnerability to addiction, including the effects of environment on gene expression.
Features of addiction include repeated (positive) drug-induced experiences, withdrawal symptoms following interruption of drug intake, and a high incidence of relapse following years of abstinence. Why is it that some people become addicted and others (under similar circumstances) do not? We do not yet know the answer to this question, but it is likely to involve a fine balance between those factors that are protective and those that present a risk.
Research and policy on drug abuse has so far focused on social deprivation and exclusion rather than altered neurobiochemistry. Addiction treatment centres in the UK combine medication, counselling, social/family support and behaviour modification to tackle cravings and aid recovery. Relapse rates, however, remain worryingly high. Many addiction centres lack a nutritional component in their treatment approaches, and there is hardly any mention of nutrition in the research literature, and little notion that diet and nutrition could have any direct role in the treatment or management of addiction.
DSM-IV sets out seven criteria (Table 1) for diagnosing substance dependence e.g. for alcohol and drugs, and an individual needs to meet at least three criteria in the same year for a diagnosis.
Table 1: DSM-IV-TR (2000) Criteria for Substance Dependence
Adapted from: APA (American Psychiatric Association). (2000) Diagnostic and Statistical Manual, ed. 4-Text Revision (TR). Washington, DC: American Psychiatric Association.
1: Tolerance Need for markedly increased amounts of a substance to achieve intoxication or the desired effect, or a markedly diminished effect with continued use of the same amount of a substance
2: Withdrawal Characteristic withdrawal syndrome for the substance or the same (or closely related) substance is taken to relieve or avoid withdrawal symptoms
3: Loss of control Substance is often taken in larger amounts or over longer period than intended
4: Reducing intake Persistent desire or unsuccessful efforts to cut or reduce substance use
5: Time consumption Great deal of time is spent to obtain the substance, use the substance, or recover from its effects
6: Effect on other activities Important social, occupational, or recreational activities are given up or reduced because of substance use
7: Persistent use Substance use is continued despite knowledge of having a persistent physical or psychological problem that is likely to have been caused or exacerbated by the substance
Substance use and dependence are frequently seen with other forms of psychological disorders, e.g. attention deficit hyperactivity disorder (ADHD), depression, anxiety, eating disorders, some personality disorders and psychosis. Patients treated for a substance use disorder or a mental health disorder should therefore always be assessed for both conditions.
Neurobiology of Drug Addiction
What is known and potential areas for nutritional management
To support recovery from addiction, treatment needs to address a number of areas, including nutrition. However, nutrition should not be considered as a primary tool of treatment in drug or alcohol addiction, but as a secondary intervention that may increase the effect and success rate of social and psychological interventions. Neuroplasticity (i.e. the brain’s ability to structurally alter itself in response to stimuli) may be enhanced by changes in diet, lifestyle and nutritional interventions. The rationale and potential areas of intervention are briefly referred to here (for an in-depth discussion on the biochemistry of addiction and nutritional management, please read Chapter 2, “Nutrition and Addiction.” (2011) Watts M (ed) ).
Recently, there has been a focus on drug-induced neuroadaptations of the brain to explain how drug addiction is able to develop and persist. Advances in neuroimaging techniques have made it possible to detect potential underlying biochemical mechanisms of addictive behaviour: changes in brain structures affecting behavioural control and decision-making skills. These brain structures are involved with reward and reinforcement and used to be part of our hardwired survival ‘toolkit’, but are hijacked by drugs of abuse and fundamentally altered. Over time the pleasure effect is reduced, promoting the repeated use of addictive substances. With chronic and long-term use of drugs, permanent changes occur to the neurobiochemistry, neuronal signaling, neurophysiology and neuroplasticity of the brain.
- The following brain areas are known to be affected by drug abuse:
- The brain stem controls basic functions critical to life such as breathing, heartbeat, and blood pressure.
- The limbic system contains the brain’s reward circuit, i.e. links brain structures that control and regulate our ability to feel pleasure
- The cerebral cortex is divided into areas that control specific functions and plays a key role in memory, attention, perceptual awareness, thought, language, and consciousness.
Addiction generally also leads to poor nutritional status, with adverse effects on fatty acid and micronutrient status, directly affecting neurotransmitter systems and brain function. Omega-3 and omega-6 fatty acids directly or indirectly impact almost all neurotransmitter systems, so their dietary availability and ratio are highly relevant in substance abuse as well as mental health disorders.
- Recreational drugs impact on different neurotransmitter systems:
- amphetamines (speed), cocaine and similar substances stimulate dopamine receptors
- heroin, morphine, codeine and others primarily activate opiate receptors
- MDMA (ecstasy) activates some 5-HT (serotonin) receptors
- cannabis or marijuana acts on receptors for the endocannabinoids (anandamide and 2-arachidonylglycerol (2-AG))
- Ketamine disrupts the brain’s glutamate receptors (resulting in sensory detachment).
The neurotransmitters dopamine, serotonin, noradrenalin, gamma-aminobutyric acid (GABA) and glutamate all play an important role in both mental illness and addiction. Much of the neurobiochemical research on drug addiction has focused on dopamine as one of the primary neurotransmitters in the structures, networks and pathways of the brain associated with reward, pleasure and well-being. Drugs of abuse cause a release of significantly higher amounts of dopamine than natural rewards (e.g. food, music, sex) and its effects tend to last longer, thereby depleting dopamine stores and potentially causing mood swings, impaired learning and poor concentration following drug use.
Nutritional strategies to increase dopamine production may improve some symptoms that are at least partially caused by a dopamine deficit after drug use. There are several known dietary, nutritional and lifestyle interventions that support the synthesis and transport of dopamine as well as helping to maintain dopamine sensitivity, including supplementation with omega-3 fatty acids, folate, vitamins B6, B12 and C, magnesium, copper, NAC and L-tyrosine. Nutrients and dietary changes supporting dopamine production may also support noradrenaline production, as noradrenaline is produced from dopamine.
Many substances of abuse increase the levels of glutamate, another key neurotransmitter, during the ‘high’. With long-term substance abuse, however, there is likely to be a glutamate deficit, affecting cerebral activity and neuroplasticity. Providing the amino acid N-acetyl-cysteine (NAC) may increase the release of glutamate. Glutamate, an excitatory and stimulatory neurotransmitter, can be converted to the inhibitory neurotransmitter gamma-aminobutyric acid (GABA) in the presence of vitamin B6 and magnesium. L-theanine (a component of green tea) may also enhance the conversion of glutamate to GABA.
Serotonin (5-hydroxytryptamine or 5-HT) is synthesized from the amino acid tryptophan, and sufficient levels of folate, vits B6, B12, C and magnesium are required for serotonin synthesis and metabolism.
Endorphins are endogenous opioid peptides that function as neurotransmitters and play a key role in the development of some addictions. Endorphin production can be significantly affected by diet. Gluteomorphins and casomorphins, for example, are peptides with opioid activity derived from gluten and casein.
Stress may lead to drug use or relapse – its effects appear to be directly linked to the activation of the hypothalamic pituitary adrenal (HPA) axis. As nutrition and lifestyle affect the stress response, a combination of diet, exercise, supplementation and lifestyle changes can be successfully employed in the management of addiction. Nutritional Therapists should, however, be aware that the sudden withdrawal (rapid detox) from alcohol, opiates and tranquilizers requires close medical supervision as it may lead to very serious (and in the case of alcohol, potentially fatal) withdrawal symptoms.
Food Addiction – does it exist?
Can foods, like drugs of abuse, be ‘addictive’? If not, are certain types of palatable foods (e.g. those rich in sugar, fat and salt) capable of triggering addictive-like behaviour and neuronal changes in certain people under specific conditions? This is a hotly debated and highly contentious subject, considering the consequences of loss of control and overconsumption, and associations with the current epidemics of obesity and related metabolic conditions. Data from the recent Health Survey for England shows that in 2009, almost a quarter of adults (22% of men and 24% of women) were obese. Obese individuals, similar to those who are dependent on drugs, have significantly lower levels of dopamine receptors according to positron emission tomographic (PET) imaging studies.
Food addiction has not been included in DSM-IV-TR (2000) due to a lack of rigorous scientific criteria and understanding of the basic mechanisms involved, particularly in humans. There is, however, some evidence for the concept of ‘food addiction’ when we compare food as a potential substance for dependence against the seven DSM-IV-TR criteria (tolerance, withdrawal, loss of control, reducing intake, time consumption, effect on other activities, persistent use).
There is also evidence that, as with substance abuse, food can trigger the release of various brain chemicals in some people with compulsive eating behaviours. , Both food and drugs have been found to involve the dopamine and opiate systems. , Some foods, e.g. sugar, carbohydrates, fats, sweet/fat combinations, processed and/or high salt foods, are potentially more ‘addictive’ than others, particularly where there is a background of food restriction. Constant food restriction may create a greater desire for certain foods in some individuals.
Medical and psychological experts should be consulted to ensure eating disorders such as bulimia nervosa and binge eating disorder have been ruled out, as these conditions are associated with addictive personality traits. A newly developed food addiction scale for identifying food addiction is still in its infancy and needs further validation, but could prove to be a useful assessment tool for identifying specific eating patterns. In combination with other treatment programmes, nutritional therapy can help to address individual biochemical imbalances and support recovery from food addiction or overwhelming food cravings. Personalised nutritional interventions simultaneously affect multiple pathways in the body, taking into account the complex interaction of individual genetic and environmental factors, potential toxic or inflammatory agents, gut dysbiosis, food intolerances, drug-nutrient interactions and nutritional imbalances or deficiencies.
The evolutionary theory behind cravings is that the seeking of natural rewards helped to ensure our survival. Now, unlimited access to food and the increasing variety of food choices undermines our health if we lose control over the ability to regulate our consumption of energy-dense foods. A new diagnostic category is therefore required to cover the role of food addiction because it probably cannot be described in the same class as a substance use disorder – although there are neurobiological similarities between the two, there are also significant differences. If the term food addiction is accepted within mainstream nutritional science, there may be more discussion about how, what, where, when and why we eat – with consequent public health legislation such as a tax on convenience food/drink and heavy restrictions on marketing. There is also likely to be more emphasis on the role and importance of novel nutritional interventions.
(With thanks to Ann Woodriff Beirne and Jane Nodder for reviewing this article).
References available on request – please contact me
Martina Watts MSc Nut Med DipION NTCC CNHC is a practising Nutritional Therapist with a focus on how to adapt physically and mentally to the dietary and environmental challenges of our age. An independent nutrition consultant at www.thehealthbank.com, she also offers training programs using nutrition science to improve resilience and performance to private and third sector organisations, as well as professionals in health, education and social care. She is editor of Nutrition and Mental Health: A handbook.
“Nutrition and Addiction. Supporting recovery from food and substance misuse with nutritional and lifestyle interventions” edited by Martina Watts is a new multi-authored handbook examining the underlying nutritional and biochemical factors involved in addictive behaviour and the importance of nutrition in the prevention and management of addiction. It also considers whether specific diet and eating patterns encourage addictive behaviour and relapse rates. Foreword by Capt Joseph Hibbeln MD. Leading practitioners and researchers explore the neurobiochemistry and nutritional management of addiction, diet in substance misusers and the prison population, food and chocolate addiction, allergy addiction syndrome, immunology and addiction and the importance of essential fatty acids and addiction (published in November 2011 by Pavilion, please visit www.pavpub.com or Tel. 01273-623222 for further details).