ON DENIAL OF PETITION FOR REHEARING
1984 OPINION NO. 96, ISSUED JULY 25, 1984, IS HEREBY WITHDRAWN AND THIS OPINION IS SUBSTITUTED THEREFOR.
SHEPARD, Justice.Claimant Hartley sustained a knee injury while working for the employer herein, Miller-Stephan. Claimant had previously had knee problems, which allegedly constituted a preexisting permanent physical impairment under I.C. § 72-332, so the State of Idaho, Industrial Special Indemnity Fund, *689was made a party to this case. The Industrial Commission determined claimant to be an odd-lot employee and awarded him total, permanent disability benefits. The employer/surety and the fund, by this appeal, dispute the commission’s findings as to claimant’s disability and challenge the finding of claimant’s odd-lot status. On the narrow ground that the commission incorrectly characterized claimant’s personality disorder as a preexisting physical impairment under I.C. § 72-332, we reverse.
Pursuant to its finding of odd-lot status, the commission awarded claimant 100% total permanent disability, which disability was broken down into the following proportions:
10% — Permanent partial impairment, which preexisted the accident, in the form of a personality disorder;
18% — Permanent partial impairment, in the form of a damaged knee, 9% being due to the industrial accident and 9% being a preexisting physical impairment;
72% — Non-medical factors (age, education, training, skills).
It is the 10% personality disorder which is problematic in this case. Because we hold that such a personality disorder, which here is not alleged to manifest itself in physical symptoms, cannot qualify as a preexisting physical impairment for purposes of imposing liability on the Industrial Special Indemnity Fund, we must reverse the 10% portion of disability which the commission gave for that impairment. We therefore decline to review the other assigned errors, all of which assume a finding of 100% total permanent disability.
The commission found that claimant suffers from a long-term avoidant personality disorder, which the commission determined constituted a preexisting permanent physical impairment of 10% of the whole man. The symptoms of this personality disorder are hypersensitivity to potential rejection, unwillingness to enter relationships, depression, humiliation, anxiety, anger, and impaired ability to function socially. This 10% impairment was factored into claimant’s disability rating to arrive at the conclusion that he is totally and permanently disabled as an odd-lot employee. See Carey v. Clearwater County Road Dept., 107 Idaho 109, 686 P.2d 54 (1984); Lyons v. Special Indemnity Fund, 98 Idaho 403, 565 P.2d 1360 (1977). The Industrial Special Indemnity Fund contest the characterization of a personality disorder as a preexisting physical impairment under I.C. § 72-332.
I.C. § 72-332, which imposes liability on the fund for physical impairments preexisting a disabling industrial accident, provides:
“72-332. Payment for second injuries from industrial special indemnity account. — (1) If an employee who has a permanent physical impairment from any cause or origin, incurs a subsequent disability by an injury or occupational disease arising out of and in the course of his employment, and by reason of the combined effects of both the pre-existing impairment and the subsequent injury or occupational disease or by reason of the aggravation and acceleration of the preexisting impairment suffers total and permanent disability, the employer and surety shall be liable for payment of compensation benefits only for the disability caused by the injury or occupational disease, including scheduled and unscheduled permanent disabilities, and the injured employee shall be compensated for the remainder of his compensation benefits out of the industrial special indemnity account.
(2) ‘Permanent physical impairment’ is as defined in section 72-422, Idaho Code, provided, however, as used in this section such impairment must be a permanent condition, whether congenital or due to injury or disease, of such seriousness as to constitute a hindrance or obstacle to obtaining employment or to obtaining re-employment if the claimant should become employed. This shall be interpreted subjectively as to the particular employee involved, however, the mere fact that a claimant is employed at the time of the subsequent injury shall not create a presumption that the pre-exist*690ing permanent physical impairment was not of such seriousness as to constitute such hindrance or obstacle to obtaining employment.” (Emphasis added.)
I.C. § 72-422 defines permanent impairment as follows:
“72-422. Permanent Impairment.— ‘Permanent impairment’ is any anatomic or functional abnormality or loss after maximal medical rehabilitation has been achieved and which abnormality or loss, medically, is considered stable or nonprogressive at the time of evaluation. Permanent impairment is a basic consideration in the evaluation of permanent disability, and is a contributing factor to, but not necessarily an indication of, the entire extent of permanent disability.”
Thus, the definition of preexisting permanent physical impairment, as stated in I.C. § 72-422 and incorporated by reference into I.C. § 72-332, does not expressly limit that term to physical, i.e., anatomical, impairments. Nonetheless, the fund argues that the word “physical” would not appear in the phrase “permanent physical impairment” within I.C. § 72-332, had not the legislature intended some significance thereby. We agree. This Court will assume that the legislature intended what it said in a statute, and we will construe statutory terms according to their plain, obvious, and rational meanings. Walker v. Nationwide Financial Corp. of Idaho, 102 Idaho 266, 629 P.2d 662 (1981); State ex rel. Evans v. Click, 102 Idaho 443, 631 P.2d 614 (1981), cert. denied, 457 U.S. 1116, 102 S.Ct. 2927, 73 L.Ed.2d 1328 (1982); Higgenson v. Westergard, 100 Idaho 687, 604 P.2d 51 (1979). We will not construe a statute in a way which makes mere surplusage of the provisions included therein. Gimlett v. Gimlett, 95 Wash.2d 699, 629 P.2d 450 (1981); Pettis v. Morrison-Knudsen Co., Inc., 577 F.2d 668 (9th Cir.1978). Therefore, we discern that the legislature intended the usual, common meaning of the word “physical” when it used that word in I.C. § 72-332. This interpretation of the preexisting physical impairment language in that statute is consistent with our requirement in other cases that the preexisting physical impairment be manifest. See Royce v. Southwest Pipe, 103 Idaho 290, 647 P.2d 746 (1982).
We do not hold that a psychological problem can never be compensated as a work-related injury or impairment. Indeed, the trend among the states in worker’s compensation law is toward the opposite result. See Larson, Workmen’s Compensation Law §§ 42.20-42.24 (1982) (nervous injury resulting from trauma experienced in the scope of one’s employment should be compensable as an industrial accident); Larson, supra, § 59.32(e) (the “second injury” principle behind industrial special indemnity funds should not be confined to loss of members, and has been extended to preexisting psychiatric conditions). Psychological disorders should be compensated, if they are proximately caused by the job environment and if they result in loss of earning capacity. Likewise, the physical symptoms indirectly caused by psychological illness might come within the definition of physical impairment, preexisting or otherwise. See Bartel v. Simplot, 106 Idaho 174, 677 P.2d 487 (1984); Larson, supra, § 59.32(e). But here we are faced with the unambiguous statutory language of I.C. § 72-332, directing that the fund should pay for preexisting physical impairments. We think the personality disorder described here, apparently lacking any bodily symptoms whatsoever, is simply too tenuous to fall within the legislature’s language of I.C. § 72-332.
The commission’s order is reversed and remanded for a redetermination of claimant’s eligibility to be placed into the odd-lot category, and for further consideration of errors raised on this appeal, in light of this decision and of our holding in Carey v. Clearwater County Road Dept., 107 Idaho 109, 686 P.2d 54 (1984).
Reversed and remanded. Costs to appellant. No attorneys’ fees on appeal.
DONALDSON, C.J., BAKES, J., and McFADDEN, J. Pro Tern, concur.