The employee appeals the compensation judge’s finding that his 1992 work injury is not a substantial contributing cause of his current psychological condition and need for treatment.  We vacate and remand to the compensation judge for reconsideration.

On February 23, 1992, Michael Massood, the employee, worked as a restaurant manager for Denny’s Restaurant, the employer.  On that date, the employee sustained low back and neck injuries and a resulting somatization disorder^[1] when he was repeatedly physically assaulted by a co-worker.  Following his injury, the employee treated extensively for multiple complaints, including treatment for neck strain and contusions, low back pain, and temporomandibular joint (TMJ) symptoms.  The employer and its insurer at that time, Gallagher Bassett Services, Inc., admitted primary liability for the employee’s neck and low back injury, and paid medical expenses related to those conditions, as well as temporary total disability benefits during his disability from work following the injury.

The employee also received extensive psychological treatment following the assault.  He initially sought counseling at MCC Managed Behavioral Care (MCC), in March 1992, where he was diagnosed with post-traumatic stress disorder.  He continued to receive counseling with a psychologist at MCC, and received ongoing medical treatment under the care of Dr. Daniel Smith, at Quello Clinic, including physical therapy to treat his neck and low back symptoms.  The employee was also referred to the Institute for Low Back Care for treatment of his neck and low back symptoms, and also for participation in its “Backs At Work” program.

In August 1992, the employee underwent a psychological evaluation with the Low Back Institute’s director of psychological services, Dr. Robert Karol.  The results of that evaluation and testing indicated mild to moderate depression; a significant concern over his physical condition which may be worsened by emotional status; a lowered sense of self-worth and self-esteem; increased anxiety and preoccupation with disrupted cognitive processing and concentration.  Dr. Karol concluded that the employee could benefit from treatment at the Institute to help him cope with his injury, and consulted with the employee on one other occasion.  In addition, Dr. Smith prescribed medication for the employee’s depression and recommended additional psychological treatment.  Although the insurer initially considered payment for psychiatric treatment to address the employee’s chronic pain problems, the employer and insurer ultimately denied payment for such treatment.

In February 1993, the employee was referred to Dr. Paul Biewen at the Fairview Southdale Hospital Pain Management Center.  Dr. Biewen indicated that the employee had symptoms that were consistent with post-traumatic stress syndrome and chronic pain syndrome, including worries about his assault at work, nightmares, night sweats, intense recollections of the events, and frequent panic symptoms while recollecting events.  Dr. Biewen recommended a pain management program, and eventually released the employee for part-time work or job search with restrictions in March 1993.  The employee completed the pain management program in April 1993.

The employee continued to treat at the Quello Clinic for periodic follow-up in 1993 and 1994.  Dr. Smith diagnosed acute and chronic depression that he related to the employee’s 1992 work injury.  The records in evidence document additional treatment the employee received from other medical providers for physical and psychological conditions.

The employee remained off work, and received temporary total disability benefits through September 1993, at the expiration of the 90-day period after which the employee had reached maximum medical improvement (MMI) from his back and neck injuries.

By claim petition, the employee sought additional temporary total disability benefits beyond September 1993, permanent partial disability benefits, and medical treatment for a TMJ condition.  The employer and insurer denied liability for the claims, and an evidentiary hearing was held on March 25, 1994, to address the claim petition.  One of the issues addressed at hearing was whether the employee had reached MMI from his 1992 injury.

In his findings and order served and filed May 12, 1994, the compensation judge found that the employee had not sustained any permanent partial disability and that the employee’s TMJ condition was not causally related to the employee’s work injury.  The compensation judge also found that as a substantial result of his work injury, the employee had sustained a somatization disorder but had not established that he suffered from post-traumatic stress disorder (PTSD).  He adopted the medical opinion of Richard Ugland, Ed.D., a licensed psychologist who conducted a psychological and employability assessment of the employee in February 1994.  The compensation judge concluded that the employee had reached MMI from his admitted neck and low back injuries as of June 1993, and had reached MMI from his somatization disorder as of March 17, 1994.  The compensation judge awarded temporary total disability benefits through 90 days post-MMI for the employee’s psychological condition.

The employee appealed from the compensation judge’s findings that the employee had reached MMI with respect to his psychological condition; that the employee did not sustain any permanent partial disability as a result of his work injury; and that the employee’s jaw complaints and TMJ syndrome were not caused or aggravated by the work injury.  This court affirmed the compensation judge’s findings.  Massoud v. Denny’s Restaurant, slip op. (W.C.C.A. Oct. 21, 1994), summarily aff’d (Minn. Jan. 30, 1995).^[2]

In June 1994, Dr. Smith diagnosed acute and chronic depression.  He referred the employee to United Behavioral Service (UBS).  The employee’s health insurance ultimately covered treatment at UBS and the employee was treated by Thomas Kuhlman, Ph.D., who diagnosed PTSD and depressive disorder.  By July 1996, Dr. Kuhlman diagnosed undifferentiated somatoform disorder,^[3] dysthymia and PTSD.  Dr. Kuhlman referred the employee to Dr. Eric Goad for a psychiatric consultation in August 1996; Dr. Goad diagnosed depression and chronic pain, and prescribed medication.  In October 1996, Dr. Smith advised that the employee had improved, but he reiterated his diagnosis of somatoform disorder and depression.  The employee continued to treat at UBS until December 1996.

On September 16, 1999, the employee underwent a psychological examination by Dr. Scott Yarosh at the employer and insurer’s request.  Dr. Yarosh diagnosed the employee with somatoform disorder and chronic pain syndrome.  He also concluded that the employee had reached MMI from both a physical and psychological standpoint.

In 2002, the employee settled his workers’ compensation claim with the employer and insurer, closing out all claims on a full, final and complete basis, with the exception of claims for future medical treatment related to his 1992 injury.  Based on the medical records in evidence, the employee has continued to seek treatment since 2002 for both his physical and medical conditions, and he decreased his already-limited number of work hours.  Although the employee had worked at a friend’s restaurant on a part-time basis since approximately 1994, he stopped working by 2002 and has not worked since that time.

The employee treated at Quello Clinic at the end of May 2007 for depression.  His treatment for depression was transferred to Dr. Robert Falk in 2008.  Dr. Falk prescribed medication and referred the employee to Behavioral Health Services, although the employee did not obtain counseling since payment for the therapy was denied by the insurer.

In November 2008, the employee called the Quello Clinic, reporting that he was anxious, hopeless, and depressed.  He was advised to go to the emergency room at Fairview Southdale Hospital, where he reported nightmares and flashbacks to his injury and chronic sleep problems, and was admitted for inpatient psychiatric care.  He was treated by Dr. Thomas Winegarden, who diagnosed anxiety and major depression, and prescribed medication.  Upon discharge from the hospital four days later, the employee was referred to Bridges at Stone Creek for an intensive outpatient program.

On January 12, 2009, the employee returned to Dr. Winegarden reporting severe pain, nightmares and flashbacks.  Dr. Winegarden diagnosed recurrent depression and PTSD.  A few weeks later he returned, feeling less depressed but still reporting panic attacks and trouble concentrating.  Dr. Winegarden continued his medication and recommended that he see a therapist.  On April 9, 2009, the employee again treated with Dr. Winegarden for worsening symptoms of depression, stating that the medications were not working.  Dr. Winegarden increased his prescribed medications.  According to a reference in Dr. Winegarden’s records, the employee apparently did not attend therapy due to lack of insurance coverage.

The employee eventually developed symptoms in his left knee which he claimed was caused by an altered gait due to his low back injury.  On October 8, 2008, the employee filed a medical request for authorization of physical therapy for that knee condition.  In his medical request, he also claimed payment for psychotropic medication and treatment related to his psychiatric treatment at Fairview Southdale Hospital.

An administrative conference was held on January 15, 2009.  The mediator presiding at the conference denied the employee’s claims, determining that there was insufficient documentation relating the need for prescription medication and his treatment at Fairview Southdale Hospital to the employee’s work injury.  The employee filed a request for formal hearing for the claimed treatment.

On January 30, 2009, the employee again underwent a psychological evaluation by Dr. Yarosh.  Dr. Yarosh again diagnosed the employee with somatoform disorder and chronic pain, and concluded that his 1992 work injury was not a substantial contributing cause of his current psychiatric condition and treatment.  Dr. Yarosh concluded that the employee

An evidentiary hearing was held on April 21, 2009.  Following that hearing, Dr. Winegarden’s deposition was taken and the parties thereafter submitted written closing arguments to the compensation judge.  In his findings and order served and filed June 18, 2009, the compensation judge found that the employee had not shown that his current depression and anxiety were related to his original injury nor to the somatoform disorder that had been diagnosed after his injury.  The judge referred to the length of time since the injury, and concluded that, based on the record as a whole, including the employee’s testimony at hearing, that the employee’s work injury was not a substantial contributing factor in his current psychological condition and need for treatment.  The employee appeals from the denial of his claim for treatment related to his psychological condition.

In an unappealed finding, the compensation judge denied the employee’s claims related to his left knee.

On appeal, the Workers' Compensation Court of Appeals must determine whether "the findings of fact and order [are] clearly erroneous and unsupported by substantial evidence in view of the entire record as submitted."  Minn. Stat. § 176.421, subd. 1.  Substantial evidence supports the findings if, in the context of the entire record, "they are supported by evidence that a reasonable mind might accept as adequate."  Hengemuhle v. Long Prairie Jaycees, 358 N.W.2d 54, 59, 37 W.C.D. 235, 239 (Minn. 1984).  Where evidence conflicts or more than one inference may reasonably be drawn from the evidence, the findings are to be affirmed.  Id. at 60, 37 W.C.D. at 240.  Similarly, findings of fact should not be disturbed, even though the reviewing court might disagree with them, "unless they are clearly erroneous in the sense that they are manifestly contrary to the weight of the evidence or not reasonably supported by the evidence as a whole.”  Northern States Power Co. v. Lyon Food Prods., Inc., 304 Minn. 196, 201, 229 N.W.2d 521, 524 (1975).

The compensation judge concluded that the employee had “not shown by a preponderance of the evidence that the February 23, 1992, work injury is a substantial contributing factor in his current need for the claimed psychological treatment and related medications.”  In his memorandum, the compensation judge concluded,

The employee argues that the evidence of record does not support the compensation judge’s denial that his work injury was a substantial contributing cause of his current psychological condition and need for treatment.  The employee claims that the evidence shows his work injury is the cause of his mental and emotional decline, citing Dr. Winegarden’s opinion that the employee has depression, panic disorder, and PTSD as a substantial result of his work injury.  The employee also contends that the compensation judge erroneously focused on language in the 1994 decision regarding the employee’s psychological condition.  The compensation judge noted in his memorandum that “the employee’s early psychological diagnoses varied but eventually PTSD was rejected and somatoform disorder established by a Findings and Order from this court.”  (Memo., p. 5.)  The employee argues that the compensation judge believed he was precluded from finding that the employee has PTSD or a psychological condition that is causally related to his work injury and that substantially contributes to his current psychological condition and need for treatment.

The employer and insurer argue that the issue of whether the employee has PTSD as a result of his work injury, and therefore whether he is entitled to payment for treatment of that condition, or for another psychological condition, has been litigated and determined.  They argue, therefore, that under principles of res judicata the earlier denial of that claimed condition is final.

Res judicata is a doctrine bringing finality to legal proceedings in which “a final judgment on the merits bars a second suit for the same claim” by the same parties.  Kaiser v. Northern States Power Co., 353 N.W.2d 899, 902 (Minn. 1984).  The res judicata effect of a prior workers' compensation determination is limited to those issues and facts material to, and determinative of, benefit eligibility and events or circumstances previously at issue and in existence as of the date of the prior hearing.  Issues involving the need for, or the reasonableness or effectiveness of, medical treatment are among those which may be affected by changed circumstances so as to preclude a res judicata effect on determinations for subsequent periods.  See Duncan v. Contact Cartage, Inc., slip op. (W.C.C.A. Nov. 30, 1994) (approval of request to change doctors affirmed “based on the changed circumstances” since prior denial of request); Cook v. Lloyd's Food Products, Inc., slip op. (W.C.C.A. Sept. 22, 1992) (prior finding denying need for surgery was not res judicata for later periods); Gullickson v. Commonwealth Elec. Co., slip op. (W.C.C.A. Nov. 28, 1989) (medical restrictions determined for a prior period were not res judicata for a subsequent period).

In this case, the initial hearing on the employee’s claim was held in 1994.  In his findings and order, the compensation judge who presided at that hearing determined that the employee’s work injury was causally related to a somatization condition but that the employee had not proven that his work injury had resulted in PTSD.  Since that first hearing, the employee’s psychological condition has persisted.  He has received ongoing psychological treatment, and he also deferred other treatment due to lack of insurance coverage.

At the hearing in 2009, the sole issue was whether the employee was entitled to payment for treatment of his psychological condition and for a left knee condition.  The compensation judge denied the claims for medical treatment.  In so doing, the judge referred to the 1994 findings, including the conclusion contained therein that the employee had developed somatoform disorder, but not PTSD, as a substantial result of his 1992 work injury.  It appears that the compensation judge felt constrained or limited by that earlier determination in the type of psychological condition that he could consider.

The record shows the employee’s ongoing need for psychological treatment and the significant amount of treatment he has received since 1994.  The employee’s circumstances have changed since the 1994 hearing and, therefore, the compensation judge need not be restricted by the initial findings concerning the nature of the employee’s psychological condition.  Res judicata does not preclude the compensation judge from finding that the employee’s psychological condition now reflects PTSD, or another diagnosis, which was causally related to his work injury.  See Hatfield v. Mark J. Lenort, No. WC09-110 (W.C.C.A. Aug. 12, 2009) (compensation judge not restricted by earlier decision indicating surgery would be allowed where the employee’s circumstances had changed).

Therefore, because it is unclear from the findings and order whether the compensation judge felt that he was precluded from determining that the employee’s work injury was a substantial contributing cause of his need for psychological treatment, we vacate the findings and order, and remand the matter to the compensation judge for reconsideration of all issues.  At the compensation judge’s discretion, he may consider additional arguments submitted by the parties.^[4]