5 evo drugs

8/13/2019 5 Evo drugs

http://slidepdf.com/reader/full/5-evo-drugs 1/20

Evolutionary theories of drug use

8/13/2019 5 Evo drugs


• What do you need to make up an evolutionary

theory for a particular human trait or

behaviour?

8/13/2019 5 Evo drugs


• Sullivan, R.J. & Hagen, E.H. 2002. Psychotropic substance-seeking:

evolutionary pathology or adaptation? Addiction 97:389-400.

• Nesse, R.M. & Berridge, K.C. 1997. Psychoactive drug use in

evolutionary perspective. Science 278:63-66.

• Ness,R.M. 1994. An evolutionary perspective on substance abuse.

Ethology and sociobiology 15:339-348.

• Muller, C.P. & Schumann, G. 2011. Drugs as instruments: A new

framework for non-addictive psychoactive drug use. Behavioral

and brain sciences 34:293-347.

8/13/2019 5 Evo drugs


• How is it possible to develop a theory of abuse

without understanding use?

8/13/2019 5 Evo drugs


Mismatch theory of drug abuse

• Coincided with influential arguments about role of dopamine in addiction

• assumes ancestors had neither access to direct routes of administration nor to ‘purifiedsubstances’

• Mismatch between emotional mechanisms evolved in a past without pure drugs or

direct routes of administration and the occurrence of these in the contemporaryenvironment (Nesse 1994, Nesse & Berridge 1997)

• Drugs ‘short-circuit’ the adaptive function of positive emotions by ‘directly stimulatingthe brain mechanisms that regulate pleasure’ (Nesse 1994).

• ‘drugs of abuse create a signal in the brain that indicates, falsely, the arrival of a huge

fitness benefit’ (Nesse & Berridge 1997).

• At the same time, drugs are used to block painful emotions, disrupting the adaptivefunction of negative affect

8/13/2019 5 Evo drugs


• There are many problems with the pleasure/denial emotional short-circuitinghypothesis

• At a neurological level it is problematized by recent studies indicating more thandopamine activity, early dopamine theories have given way to more complex

explanations

• Distinction of ‘pure drug’ now, ancestors had indirect routes is false: our ancestorsavailed themselves of a range of psychoactive chemicals

• Humans have always availed themselves of chemical rich substances, and found directmeans of ingestion

• Plants evolved chemicals to substitute endogenous NTs, not to activate a generalizedreward

• Is pleasure what really drives addiction?

8/13/2019 5 Evo drugs


Sullivan & Hagen

• Coevolution

• Content-dependent mechanism that incorporates information about plants in theancestral environment

• Nutritional constraints on brain-signaling processes: chemical rich plants can get you by

when effort or risk involved in finding food is too high

• ‘In marginal or highly variable environments, high quality food may have beenperiodically unavailable. Indeed the examples of ubiquitous drug use in antiquity alloriginate in marginal environments – desert (Ethopia and the Australian interior), aridalpine (Peru) and rain forest (Indoenisa, Malaysia). (Sullivan & Hagen 2002:395-6).

• Endogenous alkaloids replaced by allelochemicals: drug use as food

• Feeding brains

8/13/2019 5 Evo drugs


Sullivan and Hagen

• Mammalian chemical ecological adaptations are evidence of a deep time

relationship between psychotropic plants and animals

• ‘Over the approximately 200 million-year evolutionary history of

Mammalia , plants have evolved chemical defenses – neurotransmittersubstitutes – that interfere with CNS-signaling processes in plant

predators. In turn, mammals have evolved ‘counter adaptations’ to

manage plant chemicals – functional mechanisms that have been

interpreted conventionally as performing a defensive role against toxins. Is

it logical to assume that this relationship has resulted in purely defensive

mechanisms in mammals? Or is it reasonable to posit that over millions of

years mammals, including behaviorally sophisticated hominids, may have

evolved adaptations to counter-exploit the potential benefits of

psychotropic allelochemicals?’ (Sullivan & Hagen 2002:397).

8/13/2019 5 Evo drugs


Coevolution: Locks and keys,plants and mammals

• Neurotransmitters are plant-human interfaces.

• Locks and keys coevolve.

•It is no coincidence that some of our receptorsystems are named after plant drugs: nicotinic;cannabinoid; ibutenic; opioid.

• With the exception of alcohol, allelochemicals

represent all of the most commonly usedpsychoactive substances (that are ubiquitous in agiven region): tobacco, b. caapi, qat, coca, tobacco,betel nut.

8/13/2019 5 Evo drugs


Zoopharmacognosy

• Ethiopian goats on speed

• Tripping jaguars

• Boozy, lecherous monkeys

8/13/2019 5 Evo drugs


Testing the hypothesis

• ‘A controversial aspect of this model is that H.

sapiens and other mammals may have innatecontent, or knowledge, about functional

psychotropic substances’ (Sullivan & Hagen2002:397).

•

When stressed, and deprived of food, dohumans seek out allelochemicals?

8/13/2019 5 Evo drugs


Muller, C.P. & Schumann, G. 2011. Drugs as instruments: A new

framework for non-addictive psychoactive drug use. Behavioral

and brain sciences 34:293-347.

• Drugs are tools to help people adapt to changing‘microenvironments’ (i.e. from office to home, contexts associatedwith surviving to those of mating)

• ‘we suggest that people use psychoactive drugs not because theirreward systems have been ‘hijacked’, but to advance specificbehaviors relevant for fitness’ (294).

• ‘Drug instrumentalization is defined here as a learned behavior to

change one’s ownmental state by consuming a psychoactive drug.Subsequently, this altered mental state allows for the moreeffective pursuit of central survival- and reproduction-relevantgoals’ (p. 310).

8/13/2019 5 Evo drugs


Fitness

• Degree of fit: organism and environment

• Ability to stay alive long enough to breed andensure your offspring reproduce

• Ability to surviving and mate

8/13/2019 5 Evo drugs


• Most drug use, anyway you want to measure it, is not associated withaddiction

• If a majority of drug users will never become addicted, addiction cannot beexplained by chemical action

• No way of understanding addiction without understanding healthy orbeneficial drug use

• Drug behavior is either going to be:

•

Fitness irrelevant (but making the person feel ‘more fit’)

• Fitness impeding (hijacking)

• Fitness increasing: allowing for adaptation

8/13/2019 5 Evo drugs


• Increased demands for behavioral flexibility in modernity

• More and strongly differentiated microenvironments

• Demand for greater behavioral flexibility

• Proximate goal: to change mental state to perform better

• Ultimate goal: survive and reproduce

8/13/2019 5 Evo drugs


• ‘We refer to drug instrumentalization as a two step behavioralprocess: 1) the seeking and consumption of a psychoactive drug inorder to change the present mental state, which then allows for, 2)better performance of other, previously established behaviors andbetter goal achievement’ (295).

• While there are several hypotheses relating to how drugs improveperformance, cognition, ability to survive and breed, little has beendone to test these hypotheses

•

‘If a behavioral goal is, for example to socialize and to maintain asocial network, instrumental behaviors would be seeking a placewhere other people are to be found an d starting social interactionwith them’ (295).

8/13/2019 5 Evo drugs


Instrumental: goal directed

• Drug as instrument: instrument is effect on mental state

• Mental state affords variable options to dealing with the demandsof particular environments

• Coffee may allow you to drive home more safely

• Alcohol may allow you to socialize more easily, and to get laid

•

‘The ability to dynamically adapt food choice according to theorganism’s physical state base don a learning mechanism, mayhence be a basic adaptive trait in mammals, enhancing survival andreproduction’ (296-7).

8/13/2019 5 Evo drugs


• Alcohol can change mental state to:

• Reduce stress

• Enhance mood

•

Improve cognitive performance (relative to setting)• reduce clinical symptoms of depression

• improve function in the elderly (Baum-Baicker 1985)

• People learn that the mental state that alcoholproduces is good for… this is the instrumentalisation.

8/13/2019 5 Evo drugs


How commonly used drugs change mental states in

ways amenable to satisfaction of goals

• Improved social interaction: intimacy, disinhibition

• Facilitated sexual behavior (would they have ever hooked up if it weren’t for booze?)

• Improved cognitive performance and counteracting fatigue (prescription stimulants)

• Facilitated recovery from and coping with psychological stress (comfortably numb)

• Self-medication for mental problems

• Sensory curiosity – expanded perception horizon (psychedelics: novelty, learning,creativity, new ways of conceptualizing self, other and reality

• Euphoria, hedonia, and high: happiness facilitating achievement in certain domains

• Improved physical appearance and attractiveness: nicotine and steroids

8/13/2019 5 Evo drugs


• Tupper (2008): from harm minimization to benefit maximization

• Moro & Noreika (2011): critique Muller & Schumann on grounds that

psychedelics do a lot more than allow for rearranging past memories,

expanding ‘sensory and perceptual horizon’

• Human-specific metaphysical insight

• To address ‘ultimate questions that shape or shake the fundamental

worldview’

• Not just surviving, transcending, not reducible to the social and sex

5 evo drugs

Documents