The harms of substance use

People start using psychoactive substances for a variety of reasons, often without fully understanding the different types of harm associated with their use.

Common psychoactive substances include caffeine, alcohol, tobacco, cannabis, opioids (such as morphine, heroin, fentanyl, codeine, tramadol, and tapentadol), sedative-hypnotics (such as alprazolam, clonazepam, zolpidem, and diazepam), cocaine, amphetamine-type stimulants, and hallucinogens (such as psilocybin and LSD). 

Psychoactive substances act on the brain, altering mood, thinking, attention, and perception. Despite individual differences in their modes of action, most of them increase activity in the brain’s reward pathway.

This pathway consists of nerve cells that produce dopamine in response to natural rewards such as food and sex—behaviours crucial for the survival, reproduction, and fitness of a species.

These pathways are also responsible for the ‘high’ people experience after consuming psychoactive substances, contributing to repetitive use.

This repetitive use leads to long-lasting changes in the brain’s reward, stress, and impulse control circuits, which can persist for months or years, even after stopping the substances.

This leads to addiction, where individuals struggle to control their use, continue using despite negative consequences, and experience physical and emotional distress when they do not use the substance. 

It is important to recognise that the harms of psychoactive substance use can occur long before the signs of addiction appear. Identifying these harms early allows for timely intervention.

Substance use can lead to physical, psychological, social, economic, and legal harms. For example, alcohol use is associated with liver disease and pancreatitis, cardiovascular disease, and cancers (along with tobacco use).

It is also linked to nerve and brain conditions like neuropathy and cognitive impairment and is a major factor in road traffic accidents and intimate partner violence.

Alcohol and tobacco use also reduces immunity, increases susceptibility to infections, and lowers fertility rates in both men and women. In pregnant women, alcohol use can also lead to congenital defects in the unborn child.

Injecting opioids and stimulants carries a risk of spreading blood-borne viruses such as HIV, Hepatitis C, and Hepatitis B. They are also a leading cause of overdose deaths globally and increasingly in India.

Psychological harms from the use of psychoactive substances are also significant. Elevated rates of depression, anxiety, and suicide are common among those who use substances.

Cannabis and stimulants, in particular, are known to increase the risk of psychosis, a condition in which individuals lose touch with reality, develop false illogical beliefs (delusions), or experience hallucinations.

The excessive use of psychoactive substances also negatively impacts relationships and finances due to the expenses incurred both due to use and addressing physical consequences of the use.

It is one of the major reasons for decreased workplace productivity, absenteeism, and accidents. Furthermore, psychoactive substance use has been linked to higher rates of both violent and non-violent crimes, including theft, often driven by the need for money to continue using.

The harms from substance use extend beyond the individual to affect families, friends, and the broader community.

For example, a person who consumes alcohol excessively can develop liver disease but could also be the perpetrator of violence towards their spouses or lead to injury or death of a pedestrian walking on the road.

Similarly, a smoker can develop cancer themselves and also increase the risk for family members due to exposure to second-hand smoke. 

It is important to understand that harms due to substance use, including addiction, are preventable.

In terms of prevention, strategies include reducing access and availability to substances through regulation and taxation of legal substances and controlling access to illicit substances; addressing risk factors for substance use like unhealthy coping styles and underlying mental health issues, such as learning difficulties, ADHD, depression, and anxiety; and prioritising harm reduction in persons experiencing the same. 

Finally, we must understand that addiction is treatable and has similar outcomes to other chronic diseases like diabetes and hypertension. Treatment requires a thorough evaluation of both the vulnerability to and consequences of addiction and needs to be done through intervention from professionals.

Treatment involves psychotherapy that motivates people to change, learning strategies to avoid relapse, and medications to address symptoms like withdrawal, craving, and poor self-control. Finally, treatment is a process and addictions can recur. One should persist with treatment, remain supportive, and not lose hope.

(The writer is an assistant professor at Centre for Addiction Medicine, NIMMHANS, Bengaluru. This is the eighth of a DH- NIMHANS series on mental health)