My answer is 3), that pathological guilt can stem from a preaching that neglects a Theology of the Cross. Here is an example of Martin Luther, writing to his friend George Spalatin, who had become distraught over the sin of giving really bad moral advice. The conversation is best recorded in Chapter 12 of Walther's Law and Gospel. The text contains commentary from Walther himself. It is the context of Luther's "sin boldly" quote, which you may be familiar with.
Had you fully realized the awful corruption of your heart in its relation to God, you would not be so inconsolable; for you would say to yourself: Alas! the fountain is so polluted; that is why such filth has to flow from it.
VERY LONG VERSION
Apologies if it's poor form to make such an extended quote.
Let me now cite you from Luther’s writings, not so much passages in which he insists that the Gospel, pure and unalloyed, must be proclaimed to poor sinners, but rather a particular incident which illustrates how Luther brought consolation to a person who had fallen into a great and grievous sin. The party in question was that splendid man Spalatin (born 1482), who had a great share in the work of the Reformation. He became Ecclesiastical Counselor to the Elector of Saxony and lived at Altenburg. He was Luther’s intimate friend. He had been party to an advice given to a certain pastor to marry the stepmother of his deceased wife. The marriage was absolutely contrary to God’s Word, and the advice was the more appalling since the Apostle Paul, in dealing with a similar offense in 1 Cor. 5, had declared that it involved fornication such as is not so much as named among the Gentiles. When the truth dawned on good Spalatin, he refused to be comforted. Luther learned that he had fallen into melancholy. No comfort offered him would take effect. He imagined that no consolation of Scripture could apply to a man like him who had known the Word of God so well and had derived so much consolation from it.
How did Luther proceed to comfort this man? He wrote him a letter, which began as follows: (St. L. Ed. X, 1729 ff.): "Grace and peace from God in Christ and the consolations of the Holy Spirit to my worthy master in Christ, George Spalatin, superintendent of the churches in Misnia, most faithful pastor of Altenburg, my beloved in the Lord. Amen.
“My dearest Spalatin, I heartily sympathize with you and earnestly pray our Lord Jesus Christ to strengthen you and give you a cheerful heart. I should like to know, and am making diligent inquiries to find out, what your trouble may be or what has caused your breakdown. I am told by some that it is nothing else than depression and heaviness of heart, caused by the matrimonial affair of a parson who was publicly united in marriage to the stepmother of his deceased wife. If this is true, I beseech you most urgently not to become self-centered and heed the thoughts and sensations of your own heart, but to listen to me, your brother, who is speaking to you in the name of Christ. Otherwise your despendency will grow beyond endurance and kill you; for St. Paul says, 2 Cor. 7, 10: ‘The sorrow of the world worketh death.’ I have often passed through the same experience and witnessed the same in 1540, in the case of Magister Philip, who was nearly consumed by heaviness of heart and despondency on account of the landgrave’s affair. However, Christ used my tongue to raise him up again. I say this on the supposition that you have sinned and are partly to blame for the aforementioned marriage, because you approved it.”
Observe that Luther grants that Spalatin had committed a grievous wrong by approving the marriage, by advising in favor of it before it was contracted.
Luther proceeds: “Yea, I shall go further and say: Even if you had committed more numerous and grievous sins in this present and other instances than Manasseh, the king of Judah, whose offenses and crimes could not be eradicated throughout his posterity down to the time when Jerusalem was destroyed, while your offense is very light, because it concerns a temporal interest and can be easily remedied; nevertheless, I repeat it, granted you are to blame, are you going to worry yourself to death over it and by thus killing yourself commit a still more horrible sin against God?”
Luther means to say: This marriage can be dissolved, for it is not legitimate. It would be a greater sin now to despair of the mercy of God than it was to advise this marriage. For despairing of God's mercy is always the most horrible sin, because it means that we declare God to be a liar.
Luther goes on: “It is bad enough to know that you made a mistake in this matter. Now do not let your sin stick in your mind, but get rid of it. Quit your despendency, which is a far greater sin. Listen to the blessed consolation which the Lord offers you by the prophet Ezekiel, who says, chap. 33, 11: ‘As I live, saith the Lord God, I have no pleasure in the death of the wicked, but that the wicked turn from his way and live.’ Do you imagine that only in your case the Lord’s hand is shortened? Isa. 59, 1. Or has He in your case alone forgotten to be gracious and shut up His tender mercies? Ps. 77, 10. Or are you the first man to aggravate his sin so awfully that henceforth there is no longer a High Priest who can be touched with the feeling of our infirmities? Heb. 4, 15. Do you consider it a new marvel when a person living this life in the flesh, with innumerable arrows of so many devils flying about him, is occasionally wounded and laid prostrate?”
Luther means to say: Why are you surprised at your grievous fall? That is a common occurrence. The terrible part is only that we refuse to rise again and, like miserable reprobates, crawl back to the throne of grace.
Luther continues: “It seems to me, my dear Spalatin, that you have still but a limited experience in battling against sin, an evil conscience, the Law, and the terrors of death. Or Satan has removend from your vision and memory every consolation which you have read in the Scriptures. In days when you were not afflicted, you were well fortified and knew very well what the office and benefits of Christ are. To be sure, the devil has now plucked from your heart all the beautiful Christian sermons concerning the grace and mercy of God in Christ by which you used to teach, admonish, and comfort others with a cheerful spirit and a great, buoyant courage. Or it must surely be that heretofore you have been only a trifling sinner, conscious only of paltry and insignificant faults and frailties.”
There are only two ways in which Luther can explain to himself why Spalatin refuses to be comforted. Either he has hitherto failed to perceive his misery and wretchedness unders sin; he has not been aware of the fact that he is a great sinner by nature; his grievous fall had to occur in order that his eyes might be opened to these facts. Or Satan must have hidden every consolation out of Spalatin’s sight. Practically Luther says to Spalatin: Had you fully realized the awful corruption of your heart in its relaiton to God, you would not be so inconsolable; for you would say to yourself: Alas! the fountain is so polluted; that is why such filth has to flow from it.
To return to Luther: “Therefore my faithful request and admonition is that you join our company and associate with us, who are real, great, and hard-boiled sinners. You must by no means make Christ to seem paltry and trifling to us, as though He could be our Helper only when we want to be rid from imaginary, nominal, and childish sins. No, no! That would not be good for us. He must rather be a Savior and Redeemer from real, great, grievous, and damnable transgressions and iniquities, yea, from the very greatest and most shocking sins; to be brief, from all sins added together in a grand total.”
To the company of real, great, abominable sinners to which Spalatin is invited Luther feels that he belongs himself. He argues that by making our sins small, we make Christ small. That would practically amount to saying: Christ can forgive small, but not great sins.