Aim. The aim of this study is to compare different aspects of closeness in the relation of mothers towards their adult sons suffering from schizophrenia or drug addiction. Werner and Green (1996), in analyzing the concept of enmeshment, distinguish between two independent dimensions of closeness: 1) pathological - intrusiveness and 2) positive closeness-caregiving. Intrusiveness refers to a high level of separation anxiety, projective mystification, emotional inter-reactivity and possessiveness. Closeness-caregiving is associated with warmth, spending time together, nurturance, physical intimacy and consistency. Method. Mothers were divided into three groups according to the diagnosis of their sons: 1) schizophrenia, 2) drug addiction, 3) control group. Subjects completed the California Inventory for Family Assessment. Its scales showed acceptable reliability and validity. Results. Mothers perceive their interaction with drug addicted sons as less close, more aggressive and unpredictable than mothers from the control group. Unexpectedly mothers of patients with schizophrenia describe relationships with their sons in a more positive way than mothers from the control and drug addiction group (warmer, less possessive, less intense separation anxiety and less aggression). Additionally, they describe their relationships as less open and striving to avoid conflicts. Conclusions. Further studies should be conducted to verify if mothers of sons with schizophrenia describe their relations in positive terms as a result of the following: 1) self-protective bias, 2) a low level of openness or 3) good coping.