This is a compensation case. In the trial court judgment was rendered in favor of the employee against the insurance carrier *796as for total permanent incapacity payable in a lump sum. The insurance carrier appealed to the Court of Civil Appeals and that court dismissed the appeal on the ground that the district court had no jurisdiction of the case. 91 S.W.2d 1147. Writ of error was granted and this court reversed the judgment of the Court of Civil Appeals and remanded the case to that court. 132 Tex. 163, 123 S.W.2d 337. After the remand the Court of Civil Appeals affirmed the trial court’s judgment. 126 S.W.2d 1026. The case then came back here upon application of the insurance carrier, which was granted.
The Court of Civil Appeals refused to consider certain assignments of error brought forward in the brief of the appellant in that court. In this we think it erred. This case was tried before the opinion was released in Stillman v. Hirsch, 128 Tex. 359, 99 S.W.2d 270, announcing an amendment of Rule 71a governing district and county courts and under the decision in that case this case is to be governed by the rules announced in such cases as Phillips Petroleum Company v. Booles, Tex.Com.App., 276 S.W. 667. Under such rules the assignments should have been considered.
Many errors are assigned in the application. We have determined that there is one assignment which clearly must be sustained. The result of so doing will be to reverse the trial court’s judgment and remand the cause for another trial. The other errors assigned will in all probability not arise upon another trial and they will therefore not be discussed here.
The question upon which our decision is based arose in this manner: The principal fact issue to be determined in the trial court was the extent of the employee’s injuries. It was the position of the insurer that his condition was largely psychic. The employee, on the other hand, based his suit upon the ground, sustained by the jury, that he had suffered total and permanent incapacity. While a doctor was on the witness stand testifying as an expert for the insurer, a question arose as to the right of the attorney for the insurer to propound a certain question to him. The jury was retired and in its absence the court ruled that counsel could not ask the witness this question: “Let me make a record of what the doctor’s answer would be. If I should ask you the question — I am going to ask it of you now — I want you to state whether or not in your opinion this man, Henry Robinson, the plaintiff in this case, will be materially benefited when this lawsuit is tried, irrespective of the outcome of it?”
Exception was taken to the ruling of the court and it was made to appear that the doctor, if permitted, would have testified, in substance, that the condition of the claimant was largely caused by worry over his lawsuit, and that when it was finally disposed of his condition would be materially benefited. If the court erred in excluding such testimony, then the case must be retried. We are well convinced that it did err in so doing. The theory upon which expert testimony is admitted requires that the expert be permitted to state the reasons or grounds upon which his opinion is based. It also requires that the witness be permitted to testify as to what, in his opinion, caused the condition as to which he is giving expert testimony. It would have been perfectly permissible for this doctor to have testified that, in his opinion, the employee’s condition was due to a physical injury as claimed by him. In this case it is made to appear that it was the opinion of the expert that the employee’s condition was psychic, and that it was brought about or contributed to by his worrying over pending' litigation. No reason is perceived why, if as. an expert he could give it as his opinion that the condition was due to a trauma he could not for the same reason give it as his opinion that it was due to a mental agitation, whether it be brought about by grief, disappointments pending litigation or other similar cause or causes. It cannot be denied that it is a reasonable conclusion, even from the viewpoint of one not an expert in that field, that worry can bring about strange results and produce strange physical ailments. According to the record before us, the doctor would have testified, had he been permitted to do so, that, in his opinion, the employee’s condition was caused by worrying over this suit and we hold that it was error not to permit him so to testify.
We have been cited to no authority which directly supports the above holding, but to our minds it is supported in principle by Coleman Mutual Aid Association v. Muse, Tex.Civ.App., 67 S.W.2d 393, error refused; Gulf, C. & S. F. Ry. Co. v. Downs, Tex.Civ.App., 70 S.W.2d 318, 322, error refused, and by the authorities cited in support of the text in 19 Tex.Jur. p. 56, § 37. The Court of Civil Appeals at Beaumont in the case of Stedman Fruit Company v. Smith, Tex.Civ.App., 28 S.W.2d 622, held *797that it was not error to exclude testimony similar to that here involved, but no authority was cited in support of the conclusion and we are not in accord therewith.
It is the general rule that the Supreme Court does not take jurisdiction of a case on the sole question of the admissibility of evidence when same is not controlling in its character, but, the court having exercised its jurisdiction to grant the writ on the assignments upon which same was granted, it is not wanting in power to consider each and every law question presented and to render such judgment as its holdings on such questions may require. Moore v. Davis, Tex.Com.App., 27 S.W.2d 153.
For the error above pointed out, the judgments of the trial court and Court of Civil Appeals are reversed and the cause remanded.
Opinion adopted by the Supreme Court.