Those, who have not comprehended the reality of du'a (supplication), and its educative and psychological effects, have leveled various objections against it, but they are oblivious of the psychological, social, educative and spiritual effects of supplication. This is because man, in order to strengthen his determination, and eliminate his distresses, is occasionally in need of a support, and it is the du'a that lights up the lamp of hope within him.
In the words of a well-known psychologist:
“Absence of invocations amongst a nation is equivalent to the collapse of that nation! A society that has strangulated within itself the need for invocations is usually not safeguarded from degradation and degeneration. 
Du'a possesses a narcotic effect!!!
Some claim that du'a possesses a narcotic effect, instead of exhorting them towards effort and utilization of advanced means, it directs them towards supplications and teaches them that they should pray, rather than exert themselves!
But they have failed to comprehend the meaning of du'a. Supplicating to Allah (s.w.t.) does not mean that we withdraw ourselves from all the natural means that lie at our disposal and instead, raise our hands and set about praying; rather, it means that after utilizing all the means available before us to the best of our abilities and if we fall short, we resort to du'a and, by turning towards and leaning on Allah (s.w.t.), we invigorate within ourselves the spirit of hope, seeking help from the unfailing assistance of the Great Origin.
Du'a is inconsistent with ridha and taslim
The answer to the objection that the concept of du'a is inconsistent with ridha and taslim also becomes clear. This is because du'a, is a kind of quest for the ability to acquire a greater share of the infinite grace and blessings of Allah (s.w.t.).
Supplicating to Allah (s.w.t.) does not mean that we withdraw ourselves from all the natural means that lie at our disposal and instead, raise our hands and set about praying
In other words man, by means of du'a, develops within himself a great worthiness for acquiring increased blessings of Allah (s.w.t.), and it is self-evident that exertion towards perfection is, in reality, taslim in the face of the laws of creation and not something in contrast to it. It is stated in the Qur'an that God says,
Say, "What would my Lord care for you if not for your supplication?"
Du'a is a manifestation of servitude
Additionally, du'a is a kind of worship, (and an exhibition of) servitude, and by means of it man achieves a fresh attentiveness towards Allah (s.w.t.). Therefore, just as all the other acts of worship possess an educative and spiritual influence, du'a too possesses such an influence.
In other words man, by means of du'a, develops within himself a great worthiness for acquiring increased blessings of Allah (s.w.t.), and it is self-evident that exertion towards perfection is, in reality, taslim in the face of the laws of creation and not something in contrast to it
Is supplicating not interference in Allah's (s.w.t.) work?
And when they say that du'a is interference in Allah's (s.w.t.) work! Allah (s.w.t.) does whatever is advisable and prudent, they have overlooked the fact that distribution of Allah's (s.w.t.) bounties is dictated by capacity- the greater the capacity, the greater shall be the share of the Divine gifts that shall come a person's way.
And it is for this reason that Imam as-Sadiq (a.s.) has said:
“Allah (s.w.t.) has ordained ranks, which cannot be achieved except by means of supplication.”
A scholar has stated:
“When we supplicate, we link and associate ourselves to the infinite Power, Who has interconnected the entire universe.”
they have overlooked the fact that distribution of Allah's (s.w.t.) bounties is dictated by capacity - the greater the capacity, the greater shall be the share of the Divine gifts that shall come a person's way
He also states:
“Today, the most recent science, i.e. psychiatry, teaches the same things that the prophets used to teach. Why? The reason being that psychiatrists have discovered that du'a, prayers and possessing a firm conviction with respect to religion eliminate worries, anxieties, agitations and fear - factors that are cause for more than half of our inconveniences.” and 
1) Niyayish - a Persian translation of a book written by the well-known doctor and psychologist Alexis Carrol.
2) Satisfaction and pleasure over divine decree. (Tr.)
3) Submission to Allah (s.w.t.). (Tr.)
4) قُلْ مَا يَعْبَأُ بِكُمْ رَبِّي لَوْلَا دُعَاؤُكُمْ
5) إِنَّ عِندَ اللٌّهِ مَنْزِلَةً لاَ تُـنَالُ إِلاَّ بِمَسْأَلَةٍ.
al-Kafi, vol. 2, pg. 338, Chapter Fadhl al-Du'a Wa al-Haththu 'Alaihi, no. 3
6) Aain-e-Zindagi, pg. 156.
7) Ibid., pg. 152.
8) Tafsir-e-Namuna, vol. 1, pg. 639