UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 SCHEDULE 13G UNDER THE SECURITIES EXCHANGE ACT OF 1934 (AMENDMENT NO. 7)* PSYCHEMEDICS CORPORATION ------------------------ (Name of Issuer) Common Stock ------------ Title of Class of Securities 744375205 --------- (CUSIP Number) DECEMBER 31, 2003 ----------------- Date of Event which requires filing of this statement Check the appropriate box to designate the rule pursuant to which this schedule is filed: [ ] Rule 13d-1(b) [ x ] Rule 13d-1(c) [ ] Rule 13d-1(d) *The remainder of this cover page shall be filled out for a reporting person's initial filing on this form with respect to the subject class of securities, and for any subsequent amendment containing information which would alter the disclosures provided in a prior cover page. The information required in the remainder of this cover page shall not be deemed to be "filed" for the purpose of Section 18 of the Securities Exchange Act of 1934 (the "Act") or otherwise subject to the liabilities of that section of the Act but shall be subject to all other provisions of the Act (however, see the Notes). Page 1 of 11 Pages ================================================================================ CUSIP No. 744375205 Page 2 of 11 pages ================================================================================ SCHEDULE 13G AMENDMENT NO. 7 1) Names of Reporting Persons; S.S. or I.R.S. Identification Nos. of Above Persons Richard T. Christoph IRA 2) Check the Appropriate Box if a Member of a Group (See Instructions) (a) -------------------------------------------------------------------- (b) -------------------------------------------------------------------- 3) SEC Use Only ----------------------------------------------------------- 4) Citizenship or Place of Organization U.S. Citizen Number of Shares 5) Sole Voting Power 371,175 Beneficially Owned By Each Reporting 6) Shared Voting Power 0 Person With 7) Sole Dispositive Power 371,175 8) Shared Dispositive Power 0 9) Aggregate Amount Beneficially Owned by Each Reporting Person 371,175 10) Check if the Aggregate Amount in Row (9) Excludes Certain Shares (See Instructions) ----------------------------------------------------------------------- 11) Percent of Class Represented by Amount in Row (9) 7.2% 12) Type of Reporting Person (See Instructions) IN ================================================================================ CUSIP No. 744375205 Page 3 of 11 pages ================================================================================ SCHEDULE 13G AMENDMENT NO. 7 1) Names of Reporting Persons; S.S. or I.R.S. Identification Nos. of Above Persons Richard T. Christoph, Trustee of the Richard T. Christoph Living Trust, 2) Check the Appropriate Box if a Member of a Group (See Instructions) (a) -------------------------------------------------------------------- (b) -------------------------------------------------------------------- 3) SEC Use Only ----------------------------------------------------------- 4) Citizenship or Place of Organization U.S. Citizen Number of Shares 5) Sole Voting Power 78,000 Beneficially Owned By Each Reporting 6) Shared Voting Power 0 Person With 7) Sole Dispositive Power 78,000 8) Shared Dispositive Power 0 9) Aggregate Amount Beneficially Owned by Each Reporting Person 78,000 10) Check if the Aggregate Amount in Row (9) Excludes Certain Shares (See Instructions) ----------------------------------------------------------------------- 11) Percent of Class Represented by Amount in Row (9) 1.5% 12) Type of Reporting Person (See Instructions) IN ================================================================================ CUSIP No. 744375205 Page 4 of 11 pages ================================================================================ SCHEDULE 13G AMENDMENT NO. 7 1) Names of Reporting Persons; S.S. or I.R.S. Identification Nos. of Above Persons Ann B. Christoph IRA 2) Check the Appropriate Box if a Member of a Group (See Instructions) (a) -------------------------------------------------------------------- (b) -------------------------------------------------------------------- 3) SEC Use Only ----------------------------------------------------------- 4) Citizenship or Place of Organization U.S. Citizen Number of Shares 5) Sole Voting Power 3,850 Beneficially Owned By Each Reporting 6) Shared Voting Power 0 Person With 7) Sole Dispositive Power 3,850 8) Shared Dispositive Power 0 9) Aggregate Amount Beneficially Owned by Each Reporting Person 3,850 10) Check if the Aggregate Amount in Row (9) Excludes Certain Shares (See Instructions) ----------------------------------------------------------------------- 11) Percent of Class Represented by Amount in Row (9) 0.1% 12) Type of Reporting Person (See Instructions) IN ================================================================================ CUSIP No. 744375205 Page 5 of 11 pages ================================================================================ SCHEDULE 13G AMENDMENT NO. 7 1) Names of Reporting Persons; S.S. or I.R.S. Identification Nos. of Above Persons Richard T. Christoph, Trustee of the Carla C. McMahon Trust 2) Check the Appropriate Box if a Member of a Group (See Instructions) (a) -------------------------------------------------------------------- (b) -------------------------------------------------------------------- 3) SEC Use Only ----------------------------------------------------------- 4) Citizenship or Place of Organization U.S. Citizen Number of Shares 5) Sole Voting Power 43,700 Beneficially Owned By Each Reporting 6) Shared Voting Power 0 Person With 7) Sole Dispositive Power 43,700 8) Shared Dispositive Power 0 9) Aggregate Amount Beneficially Owned by Each Reporting Person 43,700 10) Check if the Aggregate Amount in Row (9) Excludes Certain Shares (See Instructions) ----------------------------------------------------------------------- 11) Percent of Class Represented by Amount in Row (9) 0.8% 12) Type of Reporting Person (See Instructions) IN ================================================================================ CUSIP No. 744375205 Page 6 of 11 pages ================================================================================ SCHEDULE 13G AMENDMENT NO. 7 1) Names of Reporting Persons; S.S. or I.R.S. Identification Nos. of Above Persons Christoph Securities, Inc. (36-275512) 2) Check the Appropriate Box if a Member of a Group (See Instructions) (a) -------------------------------------------------------------------- (b) -------------------------------------------------------------------- 3) SEC Use Only ----------------------------------------------------------- 4) Citizenship or Place of Organization Illinois Number of Shares 5) Sole Voting Power 106,600 Beneficially Owned By Each Reporting 6) Shared Voting Power 0 Person With 7) Sole Dispositive Power 106,600 8) Shared Dispositive Power 0 9) Aggregate Amount Beneficially Owned by Each Reporting Person 106,600 10) Check if the Aggregate Amount in Row (9) Excludes Certain Shares (See Instructions) ----------------------------------------------------------------------- 11) Percent of Class Represented by Amount in Row (9) 2.1% 12) Type of Reporting Person (See Instructions) CO ================================================================================ CUSIP No. 744375205 Page 7 of 11 pages ================================================================================ SECURITIES AND EXCHANGE COMMISSION SCHEDULE 13G AMENDMENT NO. 7 Item 1 (a) Name of Issuer: Psychemedics Corporation (b) Address of Issuer's Principal Executive Offices: 1280 Massachusetts Ave., Suite 200 Cambridge, MA 02138 Item 2 (a) Name of Person Filing: Richard T. Christoph IRA Richard T. Christoph, Trustee of the Richard T. Christoph Living Trust, Ann B. Christoph IRA, Richard T. Christoph, Trustee of the Carla C. McMahon Trust, and Christoph Securities, Inc. (b) Address of Principal Business Office or, if none, Residence: 1650 Tall Grass Lane Lake Forest, Illinois 60045 (c) Citizenship: All above persons are U.S. Citizens, except for Christoph Securities, Inc., which is an Illinois corporation. (d) Title of Class of Securities: Common Stock, $.005 par value (e) CUSIP NUMBER: 744375205 Item 3 If this statement is filed pursuant to Sections 240.13d-1(b), or 240.13d-2(b) or (c), check whether the person filing is a: Not Applicable ================================================================================ CUSIP No. 744375205 Page 8 of 11 pages ================================================================================ Item 4 (a) Amount Beneficially Owned: 603,325 (b) Percent of Class: 11.7% (c) Number of Shares as to which such person has: (i) sole power to direct the vote 603,325 (ii) shared power to vote or to direct the vote 0 (iii) sole power to dispose or to direct the disposition of 603,325 (iv) shared power to dispose or to direct the disposition of 0 The Shares of stock owned by each person is as follows: Richard T. Christoph IRA 371,175 Richard T. Christoph, Trustee of the Richard T. Christoph Trust 78,000 Ann B. Christoph IRA 3,850 Richard T. Christoph, Trustee of Carla C. McMahon Trust 43,700 Christoph Securities, Inc. 106,600 ------- 603,325 Item 5 Ownership of Five Percent or Less of a Class: Not Applicable Item 6 Ownership of More than Five Percent on Behalf of Another Person: Not Applicable Item 7 Identification and Classification of the Subsidiary Which Acquired the Security Being Reported on by the Parent Holding Company: Not Applicable Item 8 Identification and Classification of Members of the Group: Not Applicable ================================================================================ CUSIP No. 744375205 Page 9 of 11 pages ================================================================================ Item 9 Notice of Dissolution of Group: Not Applicable Item 10 Certification (a) Not Applicable (b) By signing below I certify that, to the best of my knowledge and belief, the securities referred to above were not acquired and are not held for the purpose of or with the effect of changing or influencing the control of the issuer of the securities and were not acquired and are not held in connection with or as participant in any transaction having that purpose or effect. After reasonable inquiry and to the best of my knowledge and belief, I hereby certify that the information set forth in this statement is true, complete and correct. February 13, 2004 Date /s/ Richard T. Christoph ---------------------------------- Signature Richard T. Christoph, on behalf of the Richard T. Christoph IRA Name/Title /s/ Richard T. Christoph ---------------------------------- Signature Richard T. Christoph, Trustee of the Richard T. Christoph Trust Name/Title ================================================================================ CUSIP No. 744375205 Page 10 of 11 pages ================================================================================ /s/ Ann B. Christoph ---------------------------------- Signature Ann B. Christoph, on behalf of the Ann B. Christoph IRA Name/Title /s/ Richard T. Christoph ---------------------------------- Signature Richard T. Christoph, as Trustee of the Carla C. McMahon Trust Name/Title /s/ Richard T. Christoph ---------------------------------- Signature Richard T. Christoph, as President of Christoph Securities, Inc. Name/Title