REPORT AND RECOMMENDATION
MARY PAT THYNGE, UNITED STATES MAGISTRATE JUDGE
On November 7, 2012, plaintiff Kenneth Arnett Solomon (“plaintiff”) filed this action against defendant Carolyn W. Colvin, Acting Commissioner of Social Security (“defendant”). Plaintiff seeks judicial review, pursuant to 42 U.S.C. § 405(g), of a decision by defendant denying his application for disability insurance benefits (“DIB”) under Title II of the Social Security Act. Presently before the court are the parties’ cross-motions for summary judgment. For the reasons set forth below, the court recommends plaintiff’s motion for summary judgment be granted, defendant’s cross-motion for summary judgment be denied, and remand to the ALJ for further consideration.
A. Procedural History
On December 29, 2009, plaintiff applied for DIB alleging disability since October 26, 2009, due to low back pain and depression. Plaintiff’s application was initially denied on May 12, 2010, and after reconsideration on September 28, 2010, plaintiff requested a hearing before an Administrative Law Judge (“ALJ”) on October 22, 2010.
On August 18, 2011, ALJ Judith Showalter held a video hearing at which plaintiff, who was represented by counsel, and a vocational expert (“VE”) appeared and testified. In a decision dated September 19, 2011, the ALJ found plaintiff not disabled.On September 14, 2012, the Appeals Council denied plaintiff’s request for review of the ALJ’s decision,  making the ALJ’s decision the final decision of the Commissioner.
On November 7, 2012, plaintiff filed a complaint seeking judicial review of the ALJ’s September 19, 2011 decision. On April 9, 2013, plaintiff filed a motion for summary judgment. In response, on May 8, 2013, defendant filed a cross-motion for summary judgment.
B. Non-Medical History
Plaintiff was born on February 15, 1962. He was forty-seven years old at the onset of his alleged depression and back disorder. He obtained a GED in 1989, and did not attend special education classes while in school. He worked in the past as a mail handler (semiskilled and light work as both generally and actually performed) and cleaner (unskilled and heavy work as generally performed and unskilled and medium work as actually performed).
The relevant time period for purposes of review in this case is October 26, 2009, plaintiff’s alleged disability onset date, through September 19, 2011, the date of the ALJ’s decision.
C. Medical History
1. Pre-Onset Date
Plaintiff served in the Army from May 4, 1979 to August 1, 1979 and from June 25, 1983 to December 12, 1984. In 1983, he injured his back in a service-related Jeep accident and, in subsequent years, reported periodic exacerbations of low back pain.He also has a history of depression, anxiety, and cocaine, crack, marijuana, heroin, opioid, and alcohol abuse. Plaintiff was employed as a housekeeper at the Wilmington Veterans Administration Medical Center (“WVAMC”)–where he has received virtually all of his medical care in this case–beginning in March 2008, after transferring to that facility from the Philadelphia Veterans Administration Medical Center (“PVAMC”), where he also worked as a housekeeper and previously received his medical care.
On April 3, 2008, Robert Dewey, NP-C, a nurse practitioner at WVAMC and plaintiff’s primary care treating source, saw plaintiff for the first time. Plaintiff stated he was previously treated for substance abuse as an inpatient and was now using drugs again. Nurse practitioner Dewey noted plaintiff’s history of low back pain, alcohol and drug abuse, depression, and anxiety, and at plaintiff’s request, referred him for a substance abuse evaluation.
On April 25, 2008, Wendy Witmer, LCSW, performed a substance abuse assessment. Plaintiff told Witmer he had not used alchohol, crack cocaine, or marijuana in more than a month. Witmer noted plaintiff was presently assessed with 40 percent service-connected disability due to a back strain. Following an interview and mental status examination, Witmer diagnosed depression and polysubstance abuse; assigned plaintiff a global assessment of functioning score (“GAF”) of 65, reflective of only mild or moderate symptoms or limitations; and referred him to both a psychologist and psychiatrist at WVAMC.
On June 19, 2008, Michelle Washington, Ph.D., a psychologist, saw plaintiff for the first time. She indicated plaintiff had recently been discharged from MeadowWood Hospital following a voluntary admission resulting from an angry altercation with his WVAMC housekeeping supervisor. Dr. Washington’s clinical impressions were major depression, anxiety disorder, and cocaine, opioid, and alcohol dependence, and she assessed plaintiff with a GAF score of 55.
On June 30, 2008, John Donnelly, M.D., a psychiatrist, saw plaintiff at WVAMC.Plaintiff told Dr. Donnelly he was no longer using drugs or alcohol and was attending AA meetings. The results of Dr. Donnelly’s mental status examination of plaintiff were essentially normal. Dr. Donnelly’s Axis I diagnoses were major depression, anxiety disorder, and cocaine, opioid, and alchol dependence, and he assigned plaintiff a GAF score of 55. Dr. Donnelly also renewed plaintiff’s prescriptions for Trazodone and Fluoxetine.
On July 23, 2008, plaintiff told Dr. Washington he had used cocaine, alcohol, and marijuana for two days the previous week.
On April 3, 2009, plaintiff told Dr. Washington he was experiencing job-related stress, financial difficulties, and back pain, but had not used drugs or alcohol for nine months and was now attending AA/NA meetings. Plaintiff’s mental status evaluation was benign, and Dr. Washington counseled plaintiff on the interaction between his depression and substance abuse.
On October 2, 2009, shortly before his onset, plaintiff complained of increased low back pain, which prevented him from working. An examination revealed pain on palpation of the sacral area, and his medications were refilled. On October 9, 2009, plaintiff told Dr. Donnelly his housekeeping job was “stressing him out, ” and Dr. Donnelly again assigned plaintiff a GAF score of 55.
2. Post-Onset Date
Plaintiff alleges his disability started on October 26, 2009. He also reported he stopped working on that date.
a. Examinations at WVAMC
On November 10, 2009, Dr. Malhotra performed a physical examination of plaintiff which showed he had a normal gait; no focal neurological deficits; full forward flexion in the trunk of the body, with limited extension and side bending; and, tenderness over the right lumbar facets. Dr. Malhotra noted plaintiff demonstrated pain behavior, moved slowly and awkwardly, and had difficulty lifting his legs off the examination table. Dr. Malhotra diagnosed plaintiff with chronic low back pain due to mild spondylosis and left lower extremity pain of unclear etiology, and she cleared plaintiff to return to work on November 12, 2009. However, plaintiff stated he tried to return to work, but was unable to do so on that or the previous day.
On December 3, 2009, plaintiff was seen for a follow-up visit at WVAMC in connection with his chronic back pain. He reported suicidal thoughts, stress related to his job, low back pain, guilt, and difficulty sleeping. He denied homicidal ideation, psychotic features, or actual suicide attempt. Plaintiff was evaluated, kept overnight, and discharged the following morning in stable condition.
On December 24, 2009, Dr. Washington examined plaintiff and reported a depressed mood and anxiety. In addition, Dr. Washington performed a mental status examination and gave plaintiff the opportunity to ventilate. Plaintiff stated his “physical and emotion issues, ‘make [him] not feel like a man.’” Dr. Washington reported plaintiff had an anxious, depressed, and tearful mood, but otherwise was calm, cooperative, appropriately dressed, and no suicidal or homicidal ideation.
On January 19, 2010, Dr. Washington reported plaintiff’s family history. She listed “traumatic events” in plaintiff’s life including his mother being abused, witnessing his brother death, and his nephew’s suicide by hanging. His father was noted to be an alcoholic.
On February 3, 2010, plaintiff underwent a neurology evaluation with Dr. Hanspal, where he reported low back pain with a numbing sensation, no weakness in the left leg, and taking opioids to control the pain. He walked using a cane. The examination revealed plaintiff leaned to the right while seated, had tenderness in the right lumbar region at L4-5, and experienced pain in the trigger areas. Dr. Hanspal’s diagnosis was chronic back pain with no evidence of radiculopathy, and he administered Lidocaine trigger point injections. During a follow-up visit on February 9, plaintiff reported no improvement.
On February 10, 2010, Dr. Washington completed a Certification of Health Care Provider under the Family and Medical Leave Act (“FMLA”). His diagnoses included major depressive disorder evidenced by a daily depressed mood most of the day, markedly diminished interests in activities, fatigue/loss of energy, feelings of worthlessness, diminished ability to concentrate, and recurrent suicidal ideation. Dr. Washington concluded plaintiff was unable to work full-time indefinitely due to his condition. Treatment included psychotherapy and medication management.
On March 4, 2010, plaintiff had a follow-up visit with Nurse Practitioner Dewey for his back pain. Plaintiff reported neither morphine nor physical therapy had improved his pain, and advised he was limiting his intake of pain medication due to excessive sweating and diarrhea. He was directed to wean off opioid medication in light of the lack of response. Dewey opined on the FMLA form that plaintiff was unable to work a full-time job for an indefinite period of time due to back pain.
Plaintiff attended physical therapy at WVAMC from approximately December 2009 to March 2010. Treatment modalities included ultrasound, massage, moist heat, manual therapy, and therapeutic exercise. The physical therapist noted plaintiff’s low back pain was due to mild spondylosis, and usually felt “good” after physical therapy session. Plaintiff, however, reported no overall improvement in his back pain upon discharge from therapy on March 16, 2010.
b. Brian Simon, Psy.D.–SSA Consultative Psychologist
On March 30, 2010, Dr. Simon performed a consultative psychological evaluation at the request of the Social Security Administration (“SSA”). Plaintiff reported the following: a history of back problems and depression since his vehicular accident in 1983; past hospitalizations for suicidal ideation on three occasions; currently receiving mental health treatment at WVAMC; and presently experiencing poor energy and motivation, difficulty sleeping, daily crying spells, poor appetite, and increased stress.Plaintiff also advised smoking cigarettes on a daily basis, but denied any alcohol or illicit drug consumption for twenty months. The evaluation revealed plaintiff to be fully oriented, guarded, and reserved, and displayed fair concentration, attention, good eye contact, a depressed mood and constricted affect. Plaintiff was found to have fair-to poor judgment and insight; coherent, relevant, and goal-directed speech; an appropriate activity level; limited abstraction ability; no signs of hyperactivity; and a good immediate memory with poor short-term memory. Plaintiff denied any hallucinations; or feeling actively suicidal. He used a cane for ambulation; was unable to perform serial calculations without any errors; and did not appear anxious. Dr. Simon’s Axis I diagnoses were major depressive disorder and polysubstance dependence, in full sustained remission. He assigned plaintiff a GAF score of 48, indicative of serious/borderline moderate symptoms of limitations.
In his report dated March 30, 2010, Dr. Simon opined plaintiff had a moderately severe impairment in sustaining work performance and attendance in a normal work setting and coping with pressures of ordinary work. However, he found plaintiff only had moderate impairment in carrying out instructions and performing routine, repetitive tasks under ordinary supervision. Dr. Simon also noted only a mild impairment to understand simple, primarily oral, instructions.
c. Brian L. Brice, M.D.–SSA Consultative Examiner
On April 2, 2010, Dr. Brice performed a consultative physical examination of plaintiff at the behest of the SSA. At that time, plaintiff reported a history of persistent and radiating low back pain and numbness, depression, and drug addiction. Dr. Brice’s examination revealed plaintiff was able to make smooth transfers, but had an antalgic gait and walked with a cane. He concluded plaintiff could perform full-time sedentary work with customary breaks; should avoid activities that require lifting, bending, and prolonged standing; and be permitted to use a single-point cane and back brace for regular work duty.
d. Jane Brandon, Ph.D. & Carlene Tucker-Okine, Ph.D.–State Agency Medical Consultants
On April 1, 2010, Dr. Brandon reviewed the record as of that date, including Dr. Simon’s consultative report, and concluded plaintiff’s depression and substance addiction disorder caused only mild restrictions in his activities of daily living; only mild difficulties maintaining social functioning; moderate difficulties in maintaining concentration, persistence, or pace; and noted one or two repeated episodes of decompensation, each of an extended duration. Dr. Brandon also considered plaintiff’s ability to perform certain work-related mental activities by completing a “Summary Conclusions” Worksheet. Out of the twenty mental activities listed therein, Dr. Brandon determined plaintiff had no significant limitations in sixteen activities and only moderate limitations in the remaining four. With respect to his mental residual functional capacity (“RFC”), Dr. Brandon concluded plaintiff’s mental impairments did not preclude him from engaging in routine workplace tasks.
On September 14, 2010, Dr. Tucker-Okine completed a Psychiatric Review Technique and a Medical RFC Assessment affirming Dr. ...