Cannabis use in adolescents: Risks and prevention.

Cannabis use by young people.

Cannabis is a drug, the consumption of which is considered illegal in Spain. Cannabis use is widespread in our country, especially among the youngest. It acts on the Central Nervous System (CNS). It has a stimulating effect at high doses and sedative at lower doses (Berrendero, 2002).

What is cannabis?

Its scientific name is “cannabis sativa” . It is known that it was already consumed almost 5000 years ago. The first references to cannabis point to the high peaks of the Himalayas as its place of origin (Indian Hemp). Marijuana and hashish are obtained from it as derivatives .

This drug is also known by other names: hashish, marijuana, pot, weed, joint, dagga, bhang, and ganja. In this article, we will use the term “cannabis” to refer to all varieties.


  • Cannabis is the illegal drug most consumed by young people in our country.
  • One in five students between the ages of 14 and 18 uses cannabis (Plan Nacional sobre Drogas, 2000).
  • Three out of ten high school students admit to having ever used it.
  • Consumption in men is more common than in women, the proportion being 23/11 respectively. (Ministry of Health, Social Services and Equality, 2017).
  • Cannabis is for some a drug that opens the door to the consumption of more dangerous drugs. This is due to the fact that habitual users of this drug are more likely to consume other types of “harder” drugs than non-cannabis users.

Basic concepts about drug use.


When talking about drugs we will use the concept proposed by the World Health Organization:

“Drug is any substance that, introduced into the body by any route of administration, produces in some way an alteration of the natural functioning of the individual’s central nervous system and is also capable of creating dependence, whether psychological, physical or both.” (WHO)

Drug’s use.

When we talk about the use of a drug we refer to the consumption of a substance in an occasional and controlled way. This use, either due to its low intensity or its infrequency, does not cause immediate damage to the person who uses it or to those around them.

The use of drugs activates the brain circuits of pleasure and euphoria, but they do not produce plastic changes in the brain . However, it could be the first step of initiation to consumption.

(1) – Leaves of the cannabis sativa or marijuana plant

Drugs abuse.

 When we speak of drug abuse we are referring to a harmful use of drugs. That is, either by consuming excessive or very repeated doses, physical or psychological damage occurs in the subject or close people.

We also speak of drug abuse when, although the doses are not excessive, they cause harmful effects due to the physical, social or mental characteristics of the user.

This form of consumption is not socially accepted.

Abuse leads to brain neuroadaptations. There is a homeostasis and the Nervous System adapts to the situation to try to restore balance. These changes are not permanent .

Only when consumption is maintained over time and frequency do we go from use to abuse.

Drug dependency.

Dependence is reached through the chronification of drug abuse.

When the subject is dependent, drug use prevails over other behaviors that, for him, previously enjoyed his preference. Most of the time is spent thinking about the use, looking for and using the drug. This leads to a degradation of their family, work and social life, which goes to the background. In this phase, there are already permanent neurobiological changes.

There are two kinds of dependency: psychic and physical dependency.

Psychic dependence.

The use of drugs produces in the consumer a feeling of well-being or pleasure. When the effect of the drug has stopped, the subject misses that pleasant sensation and feels the “psychological” need to consume again to calm the discomfort caused by the lack of consumption.

We emphasize “psychological” need because on a physical level there is no repercussion, but on a psychic level, he feels a huge desire to consume the drug.

Physical dependency.

In physical dependence there is a pathological need to consume. The body has become accustomed to the drug, and when it is lacking, serious physical and mental disorders occur. Physical dependence is closely related to the phenomenon of tolerance and withdrawal syndrome.


Tolerance occurs when a person consumes the substance continuously and their body gets used to it. That is, the same dose of drug produces less and less effect in the body and higher levels of it are required to achieve the same response (Berrendero. 2002).


We can use the WHO definition to understand addiction. It’s about a …

“Chronic and recurrent disorder characterized by compulsive drug seeking and use despite adverse consequences (social and individual, physical and emotional). The common and central characteristic of the disorder is the loss of control ”. (World Health Organization).

(2) – Cannabis is the illegal drug most consumed by adolescents

This could be a diagram showing the path that leads to addiction:

Use ▷ Abuse ▷ Addiction Setpoint ▷ Dependence ▷ Addiction.

In this transition, which goes from use to addiction, both positive and negative reinforcement are involved.

We have more and more tolerance, the drug produces less and less effect, which makes us feel bad physically and psychologically, so we will consume more to alleviate the discomfort.

Motivation goes from being a positive reinforcement ( “I use because I feel good” ) to a negative reinforcement ( “I use because I feel bad and I have to consume more to obtain the same” ).

Abstinence syndrome.

We speak of withdrawal syndrome, when an individual is addicted to the consumption of a substance, a deprivation of it is caused. Either because he cannot consume or because he is administered an antidote to the drug, severe alterations occur, both physically and psychologically.

At the popular level, the withdrawal syndrome is called “the monkey.”

Most used routes of administration in cannabis use.

The routes of administration of cannabis can be varied. The amount of the psychoactive component that reaches the Central Nervous System depends on them. This component is called tetrahydrocannabinol and is better known by its acronym THC.

Inhalation (smoke).

The consumption of marijuana in the form of a cigarette (commonly known as a joint or joint) is the best known form of cannabis use. Nowadays, it is also easy to consume it in pipes, hookahs …

In this mode of consumption, only 40% of the total THC reaches the CNS. The other 60% is lost in combustion and puffing.

Despite the fact that more than half of the THC is wasted, this form of marijuana consumption (smoked) leaves its effects on the consumer very quickly felt.

(3) – Young man smoking marijuana (most common form of consumption).

Inhalation of marijuana (vaporized).

It is one of the “healthiest” forms of cannabis consumption since with the combustion of marijuana at 230 degrees the toxins are reduced and the THC evaporates (at 180 degrees).

Oral marijuana.

The administration of marijuana orally can be through different preparations.

  • Infusion: In this case, marijuana is taken mixed with milk in an infusion. The infusion must be made with milk and not with water because THC can be dissolved in fats (fat soluble) but not in water (water soluble). When you mix marijuana with milk, the THC will stick to the fats in the milk. The more fat the milk contains, the better the herb will dissolve. As the effects of THC are dependent on digestion and milk absorption, they occur later.
  • Macerating with alcohol: Another form of oral cannabis consumption is to allow the marijuana to soak in a bottle of alcohol. This method is dangerous since we would be combining the effects of the drug with the effects of alcohol in the same consumption.
  • Cannabis sublingually: It is the most common form of medicinal use of marijuana. Today there are pharmaceutical companies that distribute tablets of extracts with the medicinal properties that marijuana provides. It is indicated for those with chronic pain, such as those caused by muscle spasticity (for example, multiple sclerosis).

Transdermal marijuana

Formerly, this form of consumption was very common. It was practiced by shamans to calm pain through an ointment with marijuana oil extract.
Remember that marijuana is fat soluble, so the base of the ointment will have to be a fatty substance (beeswax, for example).

(4) – Cannabis oil can be used transdermally

Adverse effects of cannabis use in young people.

According to Tims et al. (2002), adolescents with regular cannabis use are more likely to consume other types of substances in addition to Cannabis. This is because the pleasant effects of this substance can lead to seeking new sensations. In addition, consumption can alter cognitive functioning and therefore affect the decision to consume or not use other drugs.

Short-term effects.

  • Psychological effects: excitement, a feeling of euphoria and well-being, and then relaxation and reflection.
  • Anxiety crisis, panic attacks.
  • Increased appetite: craving for sweet food.
  • Perceptual alterations: increases the perception of colors and sounds.
  • Alterations in thinking and memory.
  • Mydriasis or dilation of the pupils.

Long-term effects.

  • Amotivational syndrome: Loss of energy and motivation to study or work.
  • Effects on the brain: Concentration, memory, learning ability, and communication are impaired.
  • Hormones: affects the menstrual cycle, decreases sperm production.
  • Negative impact on school and work performance.
  • Psychotic Disorders / Schizophrenia.
  • Anxiety disorders.
  • Drug addiction.
  • Problems with the environment (family, work and social).

(5) – Marijuana use by adolescents

Risk factors associated with cannabis use.

  • Age. Above twelve and up to sixteen there is a considerable increase in the use of this drug. This period should be considered as a vulnerable stage for the initiation of consumption. Since adolescence, consumption increases with age, although after 24 years, it begins to decline. Therefore, it reaches its peak between the ages of 18 and 24 (Pedrosa, 2009).
  • Sex Being a man is a risk factor. We have already mentioned that cannabis use is much more frequent in males.
  • Low self-esteem and a poor self-concept.
  • Lack of self-control.
  • Search for new sensations. Some young people have a tendency to seek new experiences, which are very close to self-destructive behaviors. They feel the need for different and novel sensations and experiences, which carry a taste for physical and social risk.
  • Easy accessibility to drugs or consumer close circle.
  • Harmful family environment: Alterations in family relationships can induce the use of psychotropic substances. The absence of the mother figure, an education that does not establish clear limits, parents who do not create educational ideals and goals in their children, the absence of communication between family members, family relationships lacking in affect, all this is a soup of cultivation so that the children fall into drug addiction.
  • Difficulties in establishing social relationships, the inability to express their own ideas and convictions, antisocial behaviors and difficult handling of emotions should also be considered as risk factors.

(6) – Social isolation is a risk factor for consuming cannabis

  • Lack of knowledge of the risks of long-term use of this drug.

“There is a lower perception of risk: today we are faced with a phenomenon of social tolerance, which has led to the use of cannabis being de-dramatized and demystified.” (Gutiérrez-Rojas, De Irala and Martínez-González, 2006).

Protective factors of cannabis use. 

Although these factors do not determine the NO use of cannabis, they must be taken into account as protective factors (Pedrosa, 2009).

  • Age. Several studies have shown that from the age of 24, the risk of consumption decreases.
  • Sex To be a woman.
  • High perception of risk.
  • Have access to objective and truthful information on the real effects of cannabis, without trivializing its use or ignoring its potential harm.
  • Good capacity for social interaction, resources to establish appropriate relationships adapted to reality. Knowing how to say “no” to consumer incentives.
  • Good self-esteem and self-concept.
  • Self-control.
  • Difficult accessibility to drugs.
  • Knowing how to surround yourself with good friends, avoiding dangerous circles where drug use is the norm.
  • Some attitudes, beliefs and values ​​that act as protective factors, for example, religion.
  • A healthy family relationship. A family with strong bonds of affection between its members, which fosters respect and communication, leads to a distance from the risk of drug addiction.

Mental disorders and habitual cannabis use.

Although the relevant literature is quite limited, existing studies have shown that chronic cannabis use is associated with higher rates of depression , anxiety, and psychosis (Fergusson and Bowden, 2008; Volkow et al., 2014).

Cannabis and depression.

In a previous article in this Blog, depression is defined from a medical point of view as:

“A  mood disorder , characterized by  feelings of hopelessness, unhappiness, emptiness, loneliness, dejection and guilt . It is not uncommon for suicidal ideas to appear  ”. (Castaño, G. 2017).

It has been suggested that the active ingredient in cannabis, tetrahydrocannabinol (THC), in the long term, may affect the levels of serotonin and other neurotransmitters in a way that produces depressive symptoms. (Wilson, Peart, Martin, Bridgen, Byron and Lichtman, 2002)

The more frequent the use of cannabis, the greater the depressive symptoms and the greater the severity of the depression.

Bidirectional relationship. On the one hand, many young people with depressive symptoms use cannabis to feel better. Likewise, cannabis use can cause depressive symptoms.

The cannabis-depression relationship varies with age, so the association is strongest in adolescence. The younger the consumer, the more likely they are to suffer from depression.

More frequent in girls.

Regular cannabis use, as well as early consumption, was also associated with suicidal ideation and attempts.

It is not possible to rule out that the association between cannabis and depression is due to family, social or environmental factors that increase the risk of both the use of this drug and of suffering from depression.

(7) – Cannabis abuse is frequently associated with depression.

Cannabis and anxiety.

There is normal or adaptive anxiety and abnormal or pathological anxiety .

“Anxiety is the mechanism by which the body is alert to any kind of danger. This anxiety is normal and we call it adaptive anxiety. When this alarm of the organism is triggered with great intensity or continuously, without an obvious reason, then we speak of pathological anxiety ”. (Castaño, G. 2017).

 A study by Degenhardt, Coffey, Romaniuk, et al., (2013) that has examined the relationships between cannabis use and mental health, confirms that:

High cannabis use in adolescence was associated with a doubling of the risk of anxiety disorder in adulthood.

The same happens if the consumption is not high, but it continues during the course of adolescence and persists until the age of 29.

The relationship between cannabis and anxiety disorder is also two-way. That is, many adolescents use this drug to relieve anxiety. And consumption can cause anxiety symptoms at the time of intoxication and a greater propensity for long-term anxiety disorders.

Cannabis and psychosis.

The psychoses are serious mental disorders wherein the subject undergoes a change in the way of perceiving the surrounding reality. The person may distort reality, having false beliefs about what is happening or seeing (delusions) or seeing or hearing things that do not exist (hallucinations). Disruption of speech and thought is also common.

The relationship between repeated cannabis use and the development of psychotic disorders is obvious.

In acute cannabis intoxication, psychotic symptoms such as derealization, depersonalization, a feeling of loss of control, and paranoid ideas may appear.

When cannabis use is habitual or of early onset, the risk of suffering from psychosis increases. Therefore, it is of great importance to avoid consumption in adolescents and young adults.

The adolescent brain is still developing and therefore young people are more vulnerable to the effects of drugs.

Cannabis can trigger the onset of psychosis in people with predisposing risk factors for it.

In people who already suffer from psychotic disorders, consumption would have a negative impact both on the course of the disease and on the course of treatment.

Cannabis itself is neither a necessary nor a sufficient cause, since not all people with psychosis have been exposed to cannabis use, nor do all users develop psychosis. On the other hand, it can be affirmed that the use of cannabis acts by increasing the vulnerability of the individual to suffer from psychotic disorders (Ksir and Hart, 2016).

Evidence is lacking as to whether cannabis use causes schizophrenia that would not occur without use, or whether such use simply advances the disease. (Degenhardt, Coffey and Romaniuk, 2013).

(8) – Psychoses are sometimes associated with cannabis use.

What can we do about cannabis use?

The mission of parents and educators, to avoid drug use, is to pay attention to the following points:

  • Importance of prevention.
  • Homeschooling on drugs should not be treated as a taboo subject.
  •  Psychoeducation in schools. Theoretical explanation of the consequences of consumption, exemplify with cases of consumers or former consumers.
  • The improvement of social well-being (increased job opportunities, access to education for all …), biological (easy access to health) and psychological (adequate upbringing, good level of affectivity, possibility of expressing their emotions …) can be one of the best ways to prevent drug use.
  • Management of free time and activities outside school hours (incompatible with drug use, for example, sports).
  •  Alternative leisure activities to drug use.
  •  Training in social skills and assertiveness to avoid consumption due to social desire or group pressure. Know how to say “no”.
  • Help the development of positive self-esteem. Self-confidence will be a protective factor so that adolescents do not resort to drugs in order to feel better about themselves.
  • Democratic parenting style (parents who set clear boundaries, listen to their children, promote critical thinking, are flexible, and show affection to their children).
  • Promote the autonomy of adolescents, who participate in family decision-making whenever possible.

Warning Signs.

  • It is especially important to pay attention to the warning signs (National Plan on Drugs, 2017):
  • Lack of hygiene, carelessness in dressing, dirty and unkempt appearance that appears suddenly.
  • Insomnia / nightmares / tremors.
  • Sudden weight loss or excessive appetite They start skipping school or not paying attention. Bad grades.
  • Tendency to isolate himself in the room.
  • Partial or total abandonment of their hobbies and interests.
  • Emotional lability, sudden mood swings and decreased verbal and emotional communication.
  • In case of imminent consumption, contact professionals to assess the situation and carry out an early intervention.
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Alexa Clark specializes in Cognitive Behavioral Therapy. She has experience in listening and welcoming in Individual Therapy and Couples Therapy. It meets demands such as generalized anxiety, professional, love and family conflicts, stress, depression, sexual dysfunction, grief, and adolescents from 15 years of age. Over the years, She felt the need to conduct the psychotherapy sessions with subtlety since She understands that the psychologist acts as a facilitator of self-understanding and self-acceptance, valuing each person's respect, uniqueness, and acceptance.

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