Psychoactive drugs are intended for the treatment of many different conditions and they are pretty effective; however, they are very frequently noted for the evoking addiction and therefore should be taken carefully and with consideration. Psychoactive drugs work in a way that they affect the functioning of a brain and therefore improve mood and correct behavior and they are also affect a general perception of a person. The main purposes of these drugs are therapeutic and recreational; however, the latter are less recommended and especially unattended as long as psychoactive drugs effects can be unfavorable. There are several groups of psychoactive drugs – they are stimulants and depressants as well as hallucinogens. They are aimed to either stimulate the nervous system or do otherwise; the last group alters the perception of a person pretty much. Psychoactive drugs effects are used in the spheres where it is necessary to reduce pain or to improve mental state of a person. This is what is understood under the therapeutic use. As it has already been mentioned, there is also a recreation use to these drugs. They are frequently abused and their effect should not be underestimated in this respect. Caffeine and nicotine and alcohol as well as drugs – all of them refer to psychoactive drugs and are capable of depressing and stimulating and even making a person hallucinate. Psychoactive drugs effects, if they are abused, can be pretty severe. The first group of psychoactive drugs to review is stimulants. They are aimed to speed up the process of transferring the messages to and from the brain and therefore, a person feels like there is much more energy in him or her. However, this is not so really useful for the organism. Caffeine and ephedrine are not really harmful in small and moderate quantities and they are even the part of medical preparations for treatment of some illnesses. However, in large quantities they can be rather harmful and evoke severe effects. They are capable of altering a person’s body and mind it is recommended to be very careful with and with strong preparations. Other psychoactive drugs effects can include headaches and panic attacks, a person can start experiencing anxiety and seizures; it is even possible that paranoia develops. The next and quite opposite group of psychoactive drugs is depressants. They are opiates and cannabis and they also include alcohol. They have absolutely different purpose than the previous group – they tend to slow down the processes in the brain. They relax the central nervous system. They however are also recommended in small and moderate quantities and as these psychoactive drugs effects can also be harmful. They are able to evoke such side effects as vomiting and headaches and make a person lose consciousness. Depressants make it hard for a person to concentrate properly and worsen coordination. Reaction and reflexes also deteriorate. This is the reason behind an alcohol ban while driving. The last group of psychoactive drugs is hallucinogens. They are considered the strongest in comparison to the previous two and they are also stronger when it comes to the effects. They alter the perception of a person to the extent that it makes visionary and auditory look appear differently from what it actually is. Psychoactive drugs effects hallucinogens are very serious and they should not be trifled with. It is necessary to take such drugs only under a supervision of a specialist and not abuse them. They are fraught with consequences that are often rather hard to deal with such as paranoia and irrational behaviors, let alone headaches and anxiety attacks. They can lead to renal failure and cardiac distress. Some cases of psychoactive drugs effects abuse are lethal. It should be taken into consideration that any psychoactive drugs effects are serous and that abuse can lead to the consequences that are hard to deal with. There is, unfortunately, a very sad statistics in the U.S. that tells about so many people who have acquired dependency and now have to cope with after effects. It is always better to be careful before the problem becomes serious.