Salvador Amigó

Cocaine addiction and personality: A mathematical model

The existence of a close relation between personality and drug consumption is recognized, but the corresponding causal connection is not well known. Neither is it well known whether personality exercises an influence predominantly at the beginning and development of addiction, nor whether drug consumption produces changes in personality. This paper presents a dynamic mathematical model of personality and addiction based on the unique personality trait theory (UPTT) and the general modelling methodology. This model attempts to integrate personality, the acute effect of drugs, and addiction. The UPTT states the existence of a unique trait of personality called extraversion, understood as a dimension that ranges from impulsive behaviour and sensation-seeking (extravert pole) to fearful and anxious behaviour (introvert pole). As a consequence of drug consumption, the model provides the main patterns of extraversion dynamics through a system of five coupled differential equations. It combines genetic extraversion, as a steady state, and dynamic extraversion in a unique variable measured on the hedonic scale. The dynamics of this variable describes the effects of stimulant drugs on a short-term time scale (typical of the acute effect); while its mean time value describes the effects of stimulant drugs on a long-term time scale (typical of the addiction effect). This understanding may help to develop programmes of prevention and intervention in drug misuse.

A dynamic extraversion model. The brain's response to a single dose of a stimulant drug

The aim of this paper is to present a mathematical dynamic modelling of the effect a stimulant drug has on different people which, at the same time, can be a useful tool for future brain studies. To this end, a dynamic model of the evolution of extraversion (considering its tonic and phasic aspects) has been constructed taking into account the unique personality trait theory and the general modelling methodology. This model consists of a delayed differential equation which, on one hand, considers that the active stimulus, a consequence of a single intake, is not constant; on the other hand, it contemplates that the state variable representing the phasic extraversion also represents the brain activation. The derivative of this state variable is calculated as the sum of the homeostatic control flow, the excitatory effect flow and the inhibitor effect flow. The solutions of this equation relate the tonic activation of an individual (that characterizes his or her personality) with his or her phasic activation level, whose evolution over time describes the organisms response to a single drug intake. These solutions quantitatively reproduce the predictions of current personality theories and anticipate vulnerability to drug misuse and addiction development.

General Factor of Personality Questionnaire (GFPQ): only one Factor to Understand Personality?

This study proposes a psychometric approach to assess the General Factor of Personality (GFP) to explain the whole personality. This approach defends the existence of one basic factor that represents the overall personality. The General Factor of Personality Questionnaire (GFPQ) is presented to measure the basic, combined trait of the complete personality. The questionnaire includes 20 items and is constituted by two scales with 10 items each one: the Extraversion Scale (ES) and the Introversion Scale (IS). The GFPQ shows adequate internal consistency and construct validity, while the relationships with the personality factors of other models and with psychopathology are as expected. It correlates positively and significantly with Extraversion (E) and Psychoticism (P), and negatively with Neuroticism (N) of Eysencks EPQ (Eysenck Personality Questionnaire); it correlates positively and significantly with the Sensation Seeking Scaled (SSS) of Zuckerman, and is inside the expected direction with Sensitivity to Reward (SR) and Sensitivity to Punishment (SP) of the Sensitivity to Punishment and Sensitivity to Reward Questionnaire (SPSRQ), which represent the approach and avoidance trends of behavior, respectively. It not only relates negatively with the personality disorders of the anxiety spectrum, but also with the emotional disorders in relation to anxiety and depression, and it relates positively with the antisocial personality disorder.

Self-Regulation Therapy to Reproduce Drug Effects: A Suggestion Technique to Change Personality and the DRD3 Gene Expression

Abstract This study proposes a strategy, based on self-regulation therapy, to change personality and its biological substrate, the DRD3 gene expression. It has been demonstrated that acute doses of stimulating drugs, like methylphenidate, are able to change personality and the expression of certain genes in the short term. On the other hand, self-regulation therapy has been proven to reproduce the effects of drugs. Thus, it is feasible to hope that self-regulation therapy is equally effective as methylphenidate in changing personality and the gene expression. This is a preliminary study with a single-case experimental design with replication in which 2 subjects participated. The results and potential implications for research and psychotherapy are discussed.

Experiencing Effects of Cocaine and Speed with Self-Regulation Therapy.

This study demonstrates the efficacy of Self-Regulation Therapy (SRT) to induce effects of cocaine and speed in a single session. SRT is a suggestion procedure of sensorial recall exercises (salivation, feeling of weight, tension, etc.) that increases the capacity to reproduce all sensation types and those that drugs produce. The Self-Regulation Scale (SRS) measures this capacity. Four groups participated, formed according to drug use: Group 1 (uses no illegal drugs); Group 2 (experimentally uses cannabis only); Group 3 (moderate drug users); Group 4 (regular drug users, especially stimulants). All four groups participated in an SRT session to induce relaxation. No differences in the SRS were found. Group 4 also participated in a session that reproduced effects of drugs with SRT, when Euphoria and the Effects of drugs score (high and rush) substantially increased in relation to the base-line (MD = -5.83; p < .001; and MD = -3; p < .001, respectively) and in relation to the relaxation session (MD = -4.06; p < .001; and MD = -1.96; p < .05, respectively). A profile predicting SRT efficacy was also obtained to induce the effects of cocaine and speed: low Conscientiousness and high Openness and SRS scores. Finally, the potential use of this procedure to treat addictions, and strategy development towards more controlled, responsible drug use, are discussed.

A GENETIC ALGORITHM TO CALIBRATE DYNAMICAL SYSTEMS: Confidence intervals for parameters and residuals

This paper presents a genetic algorithm to calibrate dynamical systems that is able to calculate confidence intervals for the parameters of the system. As an application case is used to calibrate the system that reproduces the dynamical response of the General Factor of Personality (GFP) to a given stimulus, particularly to a stimulant drug dose. The model is called in Literature as the response model and includes an integro-differential equation. The presented application case is a single case ABC experimental design where the stimulus is methylphenidate.

ADVANCES IN THE GENERAL FACTOR OF PERSONALITY DYNAMICS

This paper presents a dynamical integro-differential equation to reproduce the dynamical response of the General Factor of Personality (GFP) to a stimulus dose, particularly to a stimulant drug dose. The model is called in the past authors publications as response model . We refer to it as the old response model , due to a new response model presented here that solves partially the problem of the model validation: how to forecast the GFP dynamical response from a previous model calibration. The application case presented is an individual ABC experimental design where the stimulus used is methylphenidate.

LEARNING TO BE A PSYCHOSTIMULANTS ADDICT WITH SELF-REGULATION THERAPY

This article presents the results of a single-case experiment of alternative treatments in which a participant applied the Self-Regulation Therapy (SRT) to reproduce the effects of a stimulant drug, methylphenidate, and a sedative, alcohol. The SRT is a learning procedure based on classic conditioning and suggestion that reproduces the effect of drugs by remembering the effects they have. The participant reproduced the effects of both drugs during ten sessions held on 5 consecutive days. To record effects, adjective scales were used that measured Drug effect, High, Rush, Energy, Tension and the General Factor of Personality (GFP). The results indicated that the participant was capable of independently reproducing the effects of both the above-cited drugs, and that most of these effects were graphically represented as an inverted U-shape. This inverted U can be interpreted as a process in which effects of drugs become progressively more marked (sensitization) to become progressively less marked (tolerance). In this way, the inverted U represents the equivalent to a complete process of becoming addicted to a drug. The participant “learnt to be an addict” without using drugs. The theoretical implications and therapeutic potential of this procedure are discussed.

CHANCHING THE EXTERNALIZING AND INTERNALIZING SPECTRUM OF PERSONALITY WITH SELF-REGULATION THERAPY

This article presents an integrator model of changes in the externalizing and internalizing factors of personality grouped in the General Factor of Personality (GFP), based on the Unique Trait Personality Theory (UTPT) [1]. This theory proposes that a continuum exists between personality and psychopathology, as well as the existence of a GFP that occupies the apex of the hierarchy of personality, and extends from an impulsiveness-and-aggressiveness pole (externalizing spectrum) to an anxiety-and-introversion pole (internalizing spectrum). With an experimental intra-group design, 30 regular users of stimulant drugs (cocaine and amphetamine) used the Self-Regulation Therapy (SRT). The SRT is a psychological procedure based on classic conditioning and suggestion used to experience a relaxation effect after the first session, and a stimulation effect during the second session. This stimulation is achieved by reproducing, by the SRT, the sensations produced by stimulant drugs. Effects were recorded on format-state scales of personality adjectives and activation, which represented both externalizing and internalizing factors. The results showed that both relaxation and stimulation, by imitating the effects of drugs, brought about short-term changes in both the GFP, and the externalizing and internalizing factors, and also in the predicted direction, i.e., changes in global personality.

THE GENERAL FACTOR OF PERSONALITY: HISTORY OF AN INTERDISCIPLINARY VENTURE

The General Factor of Personality (GFP) is a new psychological approach of the study of the human personality that is based on the idea that, as in the case of General Intelligence, there is a personality super-factor that agglutinates and represents all the other aspects of personality. Therefore, it can be considered as a system of personality subsystems, or a global and integrated system of all the different components from the personality.