Generality
The term psychiatric drugs is a generic term, with which we want to indicate the set of all those active ingredients that act at the level of the central nervous system, influencing - in a positive or negative way - the release of different types of neurotransmitters.
The characteristics of these classes of drugs will be briefly described below.
Antidepressants
Antidepressants are psychotropic drugs widely used in the treatment of mood disorders, such as depression and bipolar disorder, but not only. In fact, these active ingredients are also used in the treatment of other disorders and pathologies, such as neuropathic pain, obsessive-compulsive disorders and even in smoking cessation therapy.
The psychotropic drugs with antidepressant action carry out their activity substantially through the modulation of the serotoninergic, noradrenergic and dopaminergic neurotransmission. More precisely, antidepressants increase the signal of these neurotransmitters.
Classification
Antidepressants can be classified according to their chemical structure or according to their mechanism of action. Therefore, this large class of drugs can be divided as follows:
- Tricyclic antidepressants (or TCA): these are the first antidepressants to be discovered, but today they are little used because of the many side effects that they are able to develop. In fact, TCAs - in addition to increasing noradrenergic and serotoninergic transmission - also act at the level of other receptor sites, thus causing various kinds of undesirable effects, some of which are also serious.
Active ingredients such as amitriptyline and clomipramine belong to this group.
- Selective inhibitors of serotonin reuptake (or SSRIs): these psychotropic drugs selectively enhance the signal of the neurotransmitter serotonin. To this group belong active ingredients such as fluoxetine, sertraline and paroxetine .
Moreover, some of these active ingredients have proved particularly useful also in the treatment of some forms of anxiety.
- Selective norepinephrine reuptake inhibitors (or NARI): the active ingredients belonging to this group selectively increase noradrenergic neurotransmission. Among these we remember the reboxetine .
- Dopamine and norepinephrine reuptake inhibitors (or DNRIs): the antidepressants belonging to this group mainly enhance dopaminergic transmission and, to a lesser extent, even noradrenergic transmission. Among these active ingredients, we recall bupropion (a drug which, among other things, is also used in smoking cessation therapy).
- Modulators of noradrenergic and serotonergic (or NASSA) transmission : this type of psychotropic drugs exerts its antidepressant action by increasing the signal of noradrenaline and serotonin through interaction with specific receptors for these two types of neurotransmitters.
The active ingredients belonging to this group include mirtazapina . Type A (or MAO-A) monoamine oxidase inhibitors : these antidepressants increase the monoamine signal by inhibiting the enzymes responsible for their metabolism. Phenelzine and moclobemide belong to this group.
- Mood stabilizers : this particular group of psychotropic drugs - to which lithium carbonate belongs - is used in the treatment of bipolar disorder.
For more detailed information about this class of drugs, we recommend reading the dedicated article already on this site: "Antidepressants".
Side effects
Being a decidedly broad class of drugs, the type of side effects that can occur following the use of antidepressants varies greatly depending on the type of active ingredient chosen, as well as on the sensitivity that each individual has towards the drug that you want to use.
anxiolytics
Anxiolytic drugs are psychotropic drugs that are used in the treatment of anxiety disorders of various kinds, such as, for example, generalized anxiety disorders, obsessive-compulsive disorders, post-traumatic stress disorders, panic attacks and phobias.
Since it is believed that anxiety disorders are related to the activity of neurotransmitters such as γ-aminobutyric acid (GABA), serotonin and noradrenaline, the anxiolytic drugs currently used in therapy act precisely at the level of the receptors for the aforementioned neurotransmitters .
Below, the main types of anxiolytic drugs usually used in therapy will be briefly described. In any case, for more information on this, see the article on "Anxiolytics - Anxiolytic drugs".
Benzodiazepines
Benzodiazepines (BZD) are psychotropic drugs widely used for the treatment of anxiety and carry out their activity through the strengthening of the GABA signal. In fact, GABA is the most important inhibitory neurotransmitter in our central nervous system.
For this reason, the increase in GABAergic transmission induced by benzodiazepines is very useful for combating anxiety disorders.
Among the various benzodiazepines used in this area, we mention diazepam and lorazepam .
For more information about the uses and side effects typical of this type of psychotropic drugs, we recommend reading the article dedicated to "Benzodiazepines".
Partial agonists of receptors for serotonin
The psychotropic drugs belonging to this group of anxiolytic drugs exert their action through the partial competition towards the receptors for serotonin 5-HT1A.
The active ingredients belonging to this group include buspirone and ipsapirone .
The main side effects induced by these active ingredients are nausea, headache and dizziness. However, unlike benzodiazepines, partial 5-HT1A receptor agonists do not cause sedation or movement disorders.
Beta blockers
Beta-blockers are used not so much for the treatment of anxiety itself as for reducing the symptoms associated with it, such as tachycardia, tremors and palpitations. Among the active ingredients belonging to this class of drugs we mention propranolol .
For more information about the mechanism of action of this type of drug, see the article on "Beta-blocker drugs".
Sedative hypnotics
Hypnotic sedatives are a particular class of psychotropic drugs used in the treatment of insomnia. For this reason, they are often referred to as "sleeping drugs".
The main drugs still used today in therapy are:
- Benzodiazepines (also endowed with anxiolytic activity as well as sedative-hypnotic activity), such as triazolam, lorazepam, lormetazepam, diazepam, flurazepam, clonazepam and bromazepam .
- Z drugs, such as zolpidem, zopiclone and zaleplon .
- Barbiturates, these psychotropic drugs were the first hypnotic sedatives to be used in the treatment of insomnia. However, due to their narrow therapeutic index, today the use of benzodiazepines or Z drugs is preferred. In fact, at the moment barbiturates are used more than anything else as antiepileptics and anesthetics.
In any case, all the psychotropic drugs mentioned above are able to exercise their sedative-hypnotic activity through the enhancement of the γ-aminobutyric acid signal, therefore through the increase of GABAergic transmission.
For more detailed information on this subject, we advise you to consult the article on "Sedative Hypnotics: Sleeping Medicines".
Antipsychotics
Antipsychotics (or neuroleptics) are psychotropic drugs used in the treatment of various forms of psychosis, such as, for example, schizophrenia, schizophreniform disorders, delusional disorders or substance-induced psychotic disorders.
Most antipsychotic drugs work by decreasing dopaminergic transmission and increasing serotonergic transmission. Indeed, it is believed that psychotic disorders may be caused by an excessive dopamine signal, which may be associated with a serotonin deficiency.
However, for more detailed information on this, we recommend reading the article "Antipsychotics - Antipsychotic Drugs".
Classification
Antipsychotics can be classified according to their chemical structure. Therefore, with this type of subdivision we can distinguish:
- Phenotiazines, to which active substances such as perphenazine and chlorpromazine belong. These psychotropic drugs exert their antipsychotic action through the antagonization of D2 dopaminergic receptors.
- Butyrrophenones, they are able to antagonize the D2 receptors and possess a certain affinity also for the 5-HT2 receptors of serotonin. Active ingredients such as haloperidol and spiperone belong to this group.
- Benzamide derivatives, such as sulpiride . These active ingredients exert an antagonistic action against D2 receptors for dopamine.
- Benzazepine derivatives, such as clozapine, quetiapine and olanzapine which exert their antipsychotic action through antagonism towards both D2 and 5-HT2 receptors.
Side effects
The type of undesirable effects and the intensity with which they can manifest themselves substantially depend on the type of active ingredient to be used, on the route of administration chosen and on the sensitivity of each individual towards the drug.
However, the side effects caused by most antipsychotics are:
- Hypotension;
- Sedation;
- Gastrointestinal disorders;
- Vision disorders;
- Malignant neuroleptic syndrome.
Stimulants of the central nervous system
This particular class of psychotropic drugs is used in the treatment of equally particular pathologies, such as, for example, narcolepsy and attention deficit hyperactivity disorder (or ADHD).
Generally, these active ingredients act by stimulating the release of monoamines, such as norepinephrine and dopamine, thus exercising a psychostimulant type of action.
The following are part of this diverse group of psychiatric drugs, active ingredients such as methylphenidate and modafinil .
