Multimodal therapy was coined by Arnold Lazarus who believed in a holistic approach to treatment with behavioral components. This therapy posits that abnormal behavior results from an array of problems (including conflicts, unhappy experiences, and social defects) and that these problems should be treated with a variety of intervention techniques. This approach expands behavioral psychology to include assessment techniques and interactions between sensory, imaging, cognitive, and interpersonal factors.

Lazarus believed that there are seven dimensions of the human personality that should be looked at when assessing and treating a disorder. These dimensions (or "modalities") are known as "BASIC I.D.":

B - Behaviors (habits, actions, reactions)
A - Affective response (emotions and moods)
S - Sensation (taste, touch, smell, sight, hearing)
I - Images (self-concept, memory, dreams)
C - Cognitions (constructs, ideas, insights)

I - Interpersonal relationships (interactions)
D - Drugs and biological functions (nutrition, exercise, etc.)

Behavior encompasses an individual's actions and conduct. Affective processes include emotions and feelings and reactions to them. Sensations are individual awareness to bodily sensations such as pain and pleasure. Imaging deals with the role of the imagination, and cognition covers analytical, planning, and reasoning skills. The interpersonal relationships component deals with relationships with others and what degree of importance they have. Lastly, drug/biological functioning concerns general health and physical well-being, bringing in biochemical/neurophysiological factors such as personal hygiene, exercise, diet, and medication use.